Ep. 504 The Pill Changes Your Brain – The Shocking Truth About Birth Control & Mental Health with Dr. Sarah Hill

Today, I am thrilled to be joined by Dr. Sarah Hill, an award-winning researcher, professor, and leading voice in the field of women’s hormones and brain health. She wrote This Is Your Brain on Birth Control and has also authored The Period Brain, which is due to be released this fall.

In our conversation, Dr. Hill dispels the myths surrounding bioidentical hormones and shares her view on how women are not biologically disordered, but just ignored by science. We dive into research on how oral contraceptives affect the brain and how the pill creates a dysregulated stress response, particularly in women with histories of adverse childhood experiences. We also explore progesterone through the lens of an evolutionary biologist and neuro-endocrinologist, highlighting its role in supporting GABAergic tone, the key differences between synthetic progestins and natural progesterone, and research on PMS and PMDD, including practical ways to manage those issues.

This helpful discussion with Dr. Sarah Hill is a must-listen for women at every stage of life.

IN THIS EPISODE, YOU WILL LEARN:

• Why has science ignored women?

• How oral contraceptives affect the way women perceive the world

• How early-life trauma impacts the ability to manage stress in adulthood

• Often-overlooked benefits of progesterone

• The different ways estrogen and progesterone impact women’s ability to build muscle mass from resistance training

• The positive effects of the GABAergic system in the brain

• The problem with combined hormone therapy

• How progesterone gets ignored and villainized, even though it can help women experience better lives

• How the protective and anti-inflammatory properties of progesterone support brain health and enhance neuroplasticity

• What the research suggests for women experiencing severe PMS or PMDD

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“Progesterone is really a lovely hormone that causes us to experience a different version of ourselves.”

– Dr. Sarah Hill

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Connect with Cynthia Thurlow  

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• Check out Cynthia’s⁠ website⁠

• Submit your questions to ⁠support@cynthiathurlow.com⁠

Connect with Dr. Sarah Hill

• On her website

• Instagram

Pre-order a copy of Dr. Hill’s new book, The Period Brain: The New Science of Why We PMS and How to Fix It, which will be on sale at the end of September.

Transcript:

Cynthia Thurlow: [00:00:01] Welcome to Everyday Wellness Podcast. I'm your host, Nurse Practitioner Cynthia Thurlow. This podcast is designed to educate, empower and inspire you to achieve your health and wellness goals. My goal and intent is to provide you with the best content and conversations from leaders in the health and wellness industry each week and impact over a million lives.

[00:00:29] Today I had the honor of connecting with Sarah Hill, an award-winning researcher, professor and thought leader in the area of women's hormones and the brain. She is also the author of This Is Your Brain On Birth Control and The Period Brain that is due out later this fall. Today we spoke at length about how women are not disordered, we're just ignored by science, the impact of oral contraceptives on brain health as well as relevant research, how the pill creates an abnormal stress response, especially in the setting of adverse childhood events, the significance of progesterone as well as a perspective from an evolutionary biologist and neuroendocrinology, why GABAergic tone is so important, why progestins are not akin to progesterone and relevant research, the impact of PMS and PMDD and ways to proactively address it. This is a truly invaluable conversation, a favorite of 2025 discussion, something that is relevant to all women irrespective of life stage.

[00:01:46] There's a quote that really stood out to me because it resonated with me both as a woman who was once in those peak fertile years, now as a menopausal female. And the quote is “Women aren't disordered, we're just ignored by science.” Why, as a researcher, as a female is a woman who is dealing within the community of research that is ongoing. Why do you think women have been so ignored by science for so long? The confounding variables around our menstrual cycle have just been, maybe it's too complicated. We don't want to have to take into account that women are in different phases of their cycle when they're participating in research. Why do you think we've been so ignored by science? 

Dr. Sarah Hill: [00:02:28] I mean, I think that you really hit the nail on the head and that is that it's more complicated to understand women. When you look at the history of science, it's like when it started as a field, our understanding of differences between the sexes was very rudimentary. It was just assumed that men and women were essentially indistinguishable from one another, with the exception that of course, females were smaller and that we have breasts and ovaries, but outside of our reproductive organs, it was just largely assumed that we were identical. And because men are easier to study because they don't cycle. And so, you can study a man, you can just pluck a man out of the population and study him, and you can get an idea of what men's bodies are like. 

[00:03:08] And the same is not true for women because, of course, women have hormones that cycle. So, research, when it first started out, and again, when we didn't really have any appreciation for the depth of sex differentiation within our physiology and within our brain, they would study men and then just apply these same principles to women with the assumption that you just shrink it and pink it. And all of a sudden it will apply to women. Now what this has created is it's created a landscape where almost all of our foundational knowledge about what it means to be human and the way that we're supposed to care for ourselves and what it means to have a normal range of emotional responses and what normal sexual desire looks like. 

[00:03:52] All of this has been built on a male template. And so, when you apply that to a female who has these cycling hormones that cycle both within a menstrual cycle, but then, of course, across the lifetime, and if you slap that, male prototype of what it means to be a normal human onto a female, we do look completely disordered. And it's because the story that we've been told about what it means to be human is a male story. And what I've been trying to do in my work is try to give people an understanding of “What's the female story?” [laughs ]Like, what are we actually supposed to look like? Because the idea that half of us are disordered, at least half of our lifetimes is completely ludicrous. 

[00:04:35] And so just trying to understand what does it actually mean to be a female with hormones that cycle across the menstrual cycle and across a lifetime is really what I'm setting out to try to do. 

Cynthia Thurlow: [00:04:46] Well, and I think it's so important because I feel like the awareness just in the last 10 to 15 years has really started to accelerate. I think especially, my generation that is going through perimenopause and menopause is demanding more. There's not as much secrecy, obviously, younger generations are just much more connected. The rise of social media apps information is disseminated in different ways. And so, I find it both fascinating and exhilarating that maybe younger generations are going to be much more body aware than certainly my generation was, which everyone listening was probably slapped on an oral contraceptive at some point because we had crazy periods. And it just seemed like it fixed a problem where there was irregular cycles, too heavy cycles, menstrual pain, I mean, all these things. It was kind of like this band-aid approach. 

[00:05:38] And so, I think in many ways these conversations are just so vital, especially irrespective of what generation you are in, I think all of us need to be talking about this and certainly making women more aware of how our hormones impact the way we perceive the world. 

Dr. Sarah Hill: [00:05:53] I was in the same boat where I was put on birth control when I was about 17, 18, and I had no idea that it was doing anything other than making me not be able to get pregnant. And I spent zero time thinking about that. So, when my first book came out, This Is Your Brain on Birth Control. That was in 2019. And even just seeing since then the way that the conversation has changed around birth control and conversations about hormones in the brain, it's been so much has happened in the last six years because when the book first came out, nobody was talking about the birth control pill and the psychological experiences that women have on it. 

[00:06:37] And then I think during the pandemic, during lockdown, people got more onto their social media and then things just really exploded and women started having these conversations. And like you said I really, I love the younger generation of women. It's like they're asking what's in their tampons. It's like they're asking all the right questions. We never thought to do any of that. 

Cynthia Thurlow: [00:06:56] No, we were [crosstalk] It was like you went to the store, you bought a tampon, you used it when you had your period. You didn't think about the fact that there might be something toxic in your tampons. You just didn't. You just assumed that it was safe. And so, I think much to the same point, about oral contraceptives that may be be clear, if you need good contraception, that's a set it and forget it as long as you can remember to take the pill every day. But I think for a lot of individuals not understanding, like, certainly for myself as I was reading your first book, really stood out to me. 

[00:07:24] It was like, “Oh my gosh.” I was thinking back to-- I had a 15-year span of time that because I had undiagnosed PCOS, a thin phenotype PCOS, didn't realize I had it till I went off the pill when I got married. And I remember having a conversation with my GYN at that time and she said, “You realize the pill just kept your hormones like steady state all the way along. And it wasn't until you were off that you actually realized you had a lack of progesterone, which contributed to worse perimenopausal symptoms. But the point that I'm making was I had terrible PMS on the pill. And I actually, when I wasn't on the pill, I had no or little to no PMS. 

[00:08:02] So, maybe we can briefly touch on some of the key items that you discovered as you were writing your first book about how oral contraceptives impact our physiology, but also the way we perceive the world. 

Dr. Sarah Hill: [00:08:17] Right. Well, so for a naturally cycling woman, what normal looks like is an ebb and flow of her two primary sex hormones. So, the first half of the cycle, which starts on the day that a woman gets her period up until about day 14, is generally when most women ovulate. During that time, you have follicle stimulation and egg development, and that process leads to the release of the sex hormone estrogen. And estrogen is known for making women feel more energetic. It makes them feel sexier, they don't need to eat as much, they move faster. It's just a period when our brain is primed for pleasure. Sexual desire is at an all-time high during the cycle. Women have more sex during that time. They feel sexy. And it's essentially the brain is like getting everything coordinated to help promote sexual behavior. 

[00:09:09] And the reason for this is, of course, this is part of-- the fertile window is in this period. And the fertile window refers to the-- it's the five days prior to ovulation and then the 24 hours that occur around ovulation. And during this period of time, sex can lead to conception. And so, because of that and because we've inherited a brain that has been shaped by reproductive success, our brain is wired for pregnancy and trying to get us pregnant. And so, because of this, during the first half of the cycle, it's a time when estrogen is high and rising, that women tend to feel sexy. They want more sex, they have energy. It's all these great things. 

[00:09:48] And then after you ovulate, the empty egg follicle actually becomes a temporary endocrine structure called the corpus luteum. And then it releases women's second primary sex hormone, which is progesterone. And progesterone, rather than coordinating a bunch of activities related to sex, which is what estrogen does, because it's all about trying to get us in a position where a sperm is going to come into proximity with an egg. Second half of the cycle is all about the implantation and pregnancy. It's about getting your body ready for the actual act of pregnancy. And so, during this time, we experience a different shift. We tend to be sleepier, we tend to be hungrier, and there's a whole host of other things that we can get into that go on during this time. 

[00:10:28] But so for a naturally cycling woman, what normal looks like is this waxing and waning of estrogen and then progesterone and sort of a waxing and waning of going from a really high energy, sexual type of a state into a sleepier, more socially conservative sort of a state. For women who are on hormonal birth control, what happens is a woman takes a pill, and every day that pill has a level of synthetic progesterone in it, or what's known as a progestin. And that progestin tells the brain not to stimulate the ovaries. And so, essentially, it prevents your ovaries from maturing egg follicles. And that's how we produce estrogen. And then, of course, the release of an egg is how we produce progesterone. 

[00:11:14] And so when you take that pill, it shuts down on your own hormone production, and instead it supplants them with this daily synthetic dose of either of progestin only or progestin plus estrogen, which is generally what's in most combination hormonal birth control products that are on the market. And this experience of having your own hormone production shut down and then having it replaced with these synthetics, of course, it creates a different psychological and physical state within the female body and within the female brain. And in particular, when you look at the research and what are the range of effects that are possible when women are on hormonal birth control? 

[00:11:52] I mean, it can affect everything ranging from who you're attracted to how much sexual desire you have. It can affect your mood. It impacts your ability to regulate stress. It can impact things like your ability to experience pleasure. So, there's this whole range of effects that can happen. And the reason that these things can happen is that hormones are actually like an incredibly important part of what our brain uses to create the experience of being the people that we are. And we know from several decades of research that for example, hormones impact sexual attraction. So, who we are attracted to and the extent of, to which we are motivated to discern the differences in quality between potential mates differs across the cycle. And in particular when estrogen is high, again because estrogen is something that's related to your ability to conceive. 

[00:12:50] Because during times in the cycle when estrogen is high, that tends to overlap with the period in the cycle when conception is possible from sex. During this time, women are really dialed in to cues related to masculinity. So, for example, testosterone cues, so masculinized male faces and voices and behaviors tend to be particularly sexy to women at this time. And we know when you're on hormonal birth control that your estrogen levels are kept super low because you're not producing any of your own. And instead, you're taking this daily synthetic. And the levels of estrogen in these synthetic pills is not very high. And instead, the dominant hormone in hormonal birth control is the progestin or the synthetic progesterone, which has the opposite effects. Actually, tamps down our interest in those kinds of qualities. 

[00:13:37] And because of this, researchers have found that women who are using hormonal birth control seem to have a less pronounced preference for cues related to facial, vocal and behavioral masculinity. This is just one tiny example. There's also a lot of research showing that women who are using hormonal birth control tend to have lower sexual desire relative to women who are not using hormonal birth control. They tend to have a greater risk of developing mood-related disorders compared to naturally cycling women. And they have dysregulated stress responses relative to naturally cycling women. So, there's this whole range of effects that occurs simply because our hormones are a really important part of what our brain uses again to create the experience of being the people that we are. 

[00:14:23] And when you interrupt that and when you interfere with that, it's going to have a sweep of psychological changes, many of which most people would never have even thought to consider. 

Cynthia Thurlow: [00:14:34] I think as more research has come out, just thinking about partner selection, the irony that you're on oral contraceptives and then you have no libido. But even more concerning to me is the changes to this hypothalamic-ovarian access that is relative to the use of oral contraceptives. Because how many women either had significant trauma as children, adverse childhood events, or are dealing with-- most of us went off to college. We had the normal stress of being students and you're getting out and getting a job or you're going to graduate school or whatever choices that you're making. And you just don't have the same stress response as someone that is not on oral contraceptives. And to me, I found that utterly fascinating. 

[00:15:18] Like you do such a great job in both your books explain this, but this to me as a middle-aged person, I was like, this explains so much about those years. We just do not have the same stress response that we would otherwise have if we were not hormonally regulated by the oral contraceptive pill. 

Dr. Sarah Hill: [00:15:37] Yeah, no, to me that was one of the most surprising things that I learned. And it was actually one of the reasons that I wrote my first book was, I was in a research talk and there was a talk about the impact of early life trauma on the functioning of the stress response in adulthood. And we know from a lot of research that if you experience early life trauma that generally you have a reduced capacity for managing stress in adulthood. And unfortunately, it's an unfortunate byproduct of trauma is that it does cause the HPA axis or essentially the stress axis to shut itself down just as a self-protective mechanism. Because if your body is just releasing cortisol nonstop, which is what happens when you're experiencing trauma, it's no good for your body. 

[00:16:23] It's good to release cortisol in little bursts when we're experiencing something stressful. Like if you and I have a couple of stressful events that happen today, like our bodies will release cortisol and that's actually part of how our body copes with stress is that it helps to regulate the whole system in response to the stress. But then when the stressor goes away, it calms down and our body's able to go back to business as usual. And that like sort of a dynamic, we call this stress like tone. like HPA axis as tone. When you have good tone, it means your body is able to respond to stressful things and like release cortisol and then calm itself down and then everything goes back to normal. 

[00:17:00] And what we see in the case of trauma, and we've known this for a very long time is that because the stress response is constantly going off, the body is like, “No, we can't do this forever.” And so, it actually shuts it down. And it does this because cortisol in the short term is really good for redistributing the body's resources to help deal with stress. But what happens when that's going on long term is that constant redistribution of all the body's resources to deal with stress means that your immune system isn't being properly fueled, and cell growth isn't being properly fueled, and brain function isn't being properly fueled, and your cardiovascular system isn't being properly fueled. And so, the whole system, if that goes on long term, falls apart. 

[00:17:43] Right, because all of your body's resources are going toward dealing with the stressor instead of doing all of the things that bodies need to do to stay alive and stay healthy. And so, I was at this research talk, and the researcher was talking about the effects of early life trauma on the functioning of the stress response. And of course, the takeaway message is the one I was just giving you. But the thing that really was striking in this talk was the researcher-- he mentioned that they collected data on something like, I think it was like 600 participants. And then he mentioned, as a throwaway note, oh, but we only analyzed data from the men in our sample because it turned out that most of the women that we collected data from were on hormonal birth control. 

[00:18:31] And everybody knows that women who are using hormonal birth control don't have a cortisol response to stress. And so, then he went on and was like, talking about other things, and I was like, “What? What? Like, everybody knows that women who are using hormonal birth control don't have a cortisol response from stress. I didn't know that. Is that real?” And then I was like, “Oh, my gosh, of course it's real.” Like, of course it's real because the hormones affect everything. And it's like, of course hormones affect sexual desire, and of course they affect sexual attraction. But also, of course they're going to affect the stress response, and of course they're going to affect the immune system. 

[00:19:02] And of course they're going to affect everything because sex hormones, like, especially in women's bodies, because we our bodies experience pregnancy, which is something that requires every single system in our body to have a makeover. Everything has to have a makeover in order to have carry a baby. All of the cells in our body are sensitive to sex hormones. There's just not a major system in the body that isn't sensitive to changes in our sex hormones. So, anytime you have sex, hormonal change, and this is true, whether we're going on the pill or it's true, when we're going through something like perimenopause or menopause, I mean, it changes us. There's just no two ways about it. Because every system in your body is sensitive to that. 

Cynthia Thurlow: [00:19:44] Yeah, it makes so much sense. Even Dr. Lisa Mosconi talks about the three Ps. She talks about puberty, pregnancy, perimenopause, and how through each one of those milestones, and most of us have gone through at least two, if not all three, it does change us physiologically, spiritually in every capacity. And I think in many ways, the more I understand now, I'm like, this explains so much. Not just about myself, my own evolution, but when I was working directly with cardiology patients and why we were seeing women at certain stages experiencing so many symptoms, like women in their 40s to me, when I was in my 20s were a mystery. I was like, clearly, whatever these women are experiencing is real, number one. I acknowledge that. 

[00:20:27] Number two, but I was like, no matter what we do, they're not sleeping well, they don't feel good, they're gaining weight, they're doing all the things that used to work. And so, I think it really speaks to the fact that, whether we blunt our hormones, whether we have hormones that are waxing and waning as we are navigating middle age, it really speaks to it changes us profoundly and significantly. And one of the things that I really took away from your new book is the role of progesterone. I think estrogen, the sexy sister estrogen, gets so much focus, and yet progesterone really is a hormone that is in greater abundance within our bodies, and yet it's kind of like. I don't want to say it's like the secondary sister, the one that doesn't get as much emphasis, but you really make the argument for why we need to be looking at progesterone differently and equally respectfully to estrogen. 

[00:21:20] So, let's talk a little bit about some of the high points and the significance of when progesterone predominates in our menstrual cycle. So, maybe going there first, but also explaining some of the effects of progesterone. Like, I think for a lot of individuals, and we've had other experts on that, have talked about people that are progesterone sensitive. So, we're speaking to the majority of women who are not progesterone sensitive or have an allergy or hypersensitivity. But what are some of the key benefits of progesterone that maybe we don't think about? I think we think of it as like, “Oh, I feel so tired in the second half of my hormone. I don't want to get off the couch. I just crave carbohydrates. What's wrong with me? All I want to do is sleep.” And it's not necessarily a bad thing. You know, their progesterone is very important. 

Dr. Sarah Hill: [00:22:04] Right. Yeah. And so, just to give you a little bit of background, I grew up, my academic discipline in the evolutionary sciences is just like every other science that has a love affair with estrogen, right? [Cynthis laughs] It's like everybody loves estrogen. It is like the darling of female neuroendocrinology. It's like everybody loves it. It does all these really beautiful things in the brain. And so, neuroscientists love it, evolutionary scientists love it because it's all about conception and attraction. And these are things that evolutionary biologists like to study. And so, it's like super interesting to them for those reasons. And I mean, and it was discovered first and it was like, “Oh, look at this, men have testosterone and women have estrogen. And then isn't that nice? And we'll tie it up with a neat little bow.” And then that's the end of the story. 

[00:22:52] But it's not the end of the story. Women and female mammals, we produce two primary sex hormones, right? We have estrogen and then we have progesterone. And even though that little menstrual cycle map that all of us have seen pictures of a gazillion times always shows this big bump of estrogen and then this slightly bigger, sometimes same size bump of progesterone. Those aren't actually drawn to scale. And generally, they have it scaled down where the Y axis on the estrogen side is 100 times lower than the Y axis on the progesterone side, because progesterone is released in 100 times quantities relative to estrogen. 

[00:23:36] So, it's like our bodies produce more of it. And so, the rise and fall of it is a lot more dramatic than the rise and fall of estrogen and the impact in the body is profound. And because estrogen, it's the hormone of sex and feeling sexy and energetic, it's like the one that everybody tends to want to pay attention to. But it turns out that progesterone is just as important, and in some ways, I think more important just in the things that it can possibly do with things like hormone therapy, which I think that we can get to, but progesterone. 

So, if we think about the cycle, I always think about the cycle as being divided into two halves and it's a little bit more complex than that. 

[00:24:18] But the really, sort of simple way of thinking about it is that a woman cycle, and let's just assume a 28-day cycle, even though that's not usually exactly how it works for people. But the first 14 days is like your body and your brain, everything is getting geared up for conception. And again, it's like all of the red carpet is laid out for things related to feeling sexy and energetic. And everything, is geared toward mate attraction, being able to distinguish between high and low-quality mates and then sexual desire. And so, we tend to see, as I've noted, that women tend to feel really sexy. They tend to have more sex. And all that is so fun. 

[00:25:01] And like if you look at what goes on at the level of the neuron, you get these like beautiful little branches going off the spines and your neurons that are making you more sensitive to the environment so things smell better and more intense. [Cynthia laughs] And I mean it's just like things are tastier. Like you get-- our reward centers get primed. And so, it's like this really sexy and fun time in the cycle. And then all of a sudden, if we think about like a task analysis on the menstrual cycle, first half of the cycle is all about attraction and sex. Second half of the cycle is charged with implantation and pregnancy. 

[00:25:39] And so, we have two different jobs that our bodies have to accomplish over the course of a cycle. We have to have sex and then we have to implant an embryo and get pregnant. And so that's kind of what our body is doing is it's shifting us between these two states. And again, estrogen is the sexy and fun one. And so, there's been a lot of attention given to it. But what goes on during the second half of the cycle is our body really is changing gears. It's shifting gears and it's shifting us away from this time when it's about energy expenditure, right, and going out and searching for mates and telling the difference between a high and low-quality mate and having sex and attracting partners. 

[00:26:20] And it's like drawing our energy inward. And so instead of being a time of energy expenditure, it's a time of energy conservation. And so, women tend to become sleepier and tired because their body is trying to conserve energy, but also because our body is using more energy. And so, one of the things that women are not told, and again, this is all comes down to that one size fits all set of ideas about what it means to be human that we've inherited from a science that was based on research done exclusively on men, is this idea that our energy needs are essentially invariant across from one day to the other. 

[00:26:59] And this just simply isn't true for women because the second half of the menstrual cycle, when the body is preparing for the possibility of pregnancy, our energy needs to go up to such a degree that our basal metabolic rate increases by about 11%. And this might not sound that dramatic. 11% doesn't sound like a big number. If you told me that there was a shoe sale, right, [Cynthia laughs] I'd say if they have 11%, even my girl math, I don't think that I'd feel like I need to go shopping. 

[00:27:29] But for somebody who eats 2,000 calories a day, let's say, which is supposed to be a baseline average or whatever, this is almost an extra 165 or so calories a day that you need that your body is using during the second half of the cycle compared to the first half of the cycle. And now what happens is you give women a one size fits all set of calorie recommendations that we've all been handed down. Like this is how many calories you need as a healthy adult or an active adult or an inactive adult. And what happens when women are sticking to that in the second half of their menstrual cycle? They're hungry, they're tired, and they're pissed off because they are like, [Cynthias laughs] “Why am I so hungry?” 

[00:28:09] And then they start internalizing these messages that they tell themselves which is like, “I have no self-control, like, why can't I do this?” And I think so many women have this narrative that their body is the enemy. That it's essentially the thing standing between themselves and their goals is their body. And I think that narrative largely exists because women have been given a false set of ideas about who they're supposed to be and what their body actually needs. Because I think that if women understood this, if we were taught this, because I didn't learn this stuff until very recently myself. And so, I've had these same stories. 

[00:28:47] And when I look back on it, I'm like, “Gosh, how many hours did I waste, beating myself up for being tired or being hungry or some of these other things that we'll talk about, as we move through the book and the luteal phase.” But it's like I was at war with myself because I was given a bad bill of goods. I was holding inaccurate information about what my body needs. And we do need more energy. Our basal metabolic rate goes up during this time. And the reason for this-- And again, this is one of these things that doesn't sound like it should be that costly, but like, building all of that new tissue for the endometrial layer actually ends up being incredibly costly. 

[00:29:28] And it depletes us of critical amino acids, it depletes us of energy, it makes us tired, and it's something that most of us aren't told about. 

Cynthia Thurlow: [00:29:38] It's so interesting to me because I 100% agree that we are conditioned to restrict and feel shame and be hyper focused on our bodies. And then you add in younger women that have got all of this augmented vision, information that they see on social media or in print, even if people still read magazines, but things you see in movies that have all been digitally altered. And it's like, if women were taught, like, “Oh, by the way, the last two weeks of your cycle, you may be hungrier. So, you may want to consume an additional 100, 150 calories, good quality carbohydrates or protein or whatever it is that you need,” how much better would people feel knowing that information? 

[00:30:17] If women were taught that at a very early age, not the embarrassing 4th and 5th grade where they separate the girls and the boys. And like, everyone knows what's going on in the opposite gender classroom. And yet in many instances, for some people, that is all the education that they get. They get little-to-no education about their bodies and what to expect and then they get into-- I can only speak from the perspective of a parent of boys. I think there's a lot less pressure on boys versus younger women in terms of expectations. 

[00:30:51] But even just being around my children's friends, the things I hear young women saying, it's always this, focus on control and restriction and these are healthy people that are thinking these things. So, you can just imagine you add in like lack of access to information about our bodies and it just exacerbates all of this.

Dr. Sarah Hill: [00:31:11] Right Well, no, for sure, for sure. And it makes me angry to think about yes, we were force fed these expectations about what we're supposed to be doing and it's based on information that wasn't designed for us, because it's not just, okay, well, you know, you're going to be hungry at this time. It's like your body's actually burning more calories at this time. So, it's not just like you're hungry or because your body is secretly trying to make you look a way that you don't want to look. It's like your body needs this because it's using it right now and you are tired right now and it's okay to be tired because of the way that your motivational system shifts in response to your hormones. 

[00:31:50] Because progesterone, again, if we understand our body as shifting between two different states, I'm trying to get pregnant state, which is about sex and energy and then I'm trying to get pregnant, which is about conserving energy and resting and being safe. It really helps to put some of these experiences that we have, whether they're psychological changes that we have with mood or motivational states because our motivation also decreases at this time. So, like generally women feel less motivated to go out and get them. Like “Go, get them.” 

Cynthia Thurlow: [00:32:21] Like I'm going to stay on the couch, I'm going to be in my pajamas and I want that bag of chips. 

Dr. Sarah Hill: [00:32:21] Yeah, I mean it's like our energy levels lower and our desire to achieve it gets the brakes tapped on it a little bit. And again, it's because our body is trying to keep up safe and it's trying to conserve energy during this time. And if we honor that and nurture that, I think that most of us can end up feeling a lot better than we do right now, because I know that even in my own life. And it's so funny because as a researcher, it's like you can read things in a science paper a thousand times and you're like, “I know that this is real.” I've seen this. But then you still tell yourself the story about the way that you're doing things is better. 

[00:33:03] And just [Cynthia laughs] to give you an example of this, I'll talk about exercise for me, I had been reading about the impact of our sex hormones on the ability to build muscle mass from resistance training. And what the research shows is that if you do identical workouts, and you do them in your follicular phase when estrogen is high, or you do them in your luteal phase when progesterone is high, you get different results. And the reason for this is estrogen causes-- it initiates a whole cascade of physiological changes that help to promote muscle growth and repair. And progesterone does the opposite because progesterone, actually, it likes to break things down for use in the endometrial layer because it wants to use that for growth of the endometrial layer. 

[00:33:50] And estrogen likes to build things. And so, I'd read papers where they've done different types of studies looking at women doing resistance training in the luteal phase or the follicular phase, and da, da, da. And I'd always thought, okay, I should probably, because I work out, I'm somebody, I like to go to the gym and I like to stay fit. And it has always been, always been for me a struggle to do especially heavy lifting during the luteal phase. I feel tired and I feel weak, but rather than going with my body, [Cynthia laughs] I'd always fight it and like, muscle through, muscle through, muscle through. Because I was afraid of deviating from my one size fits all workout. Because it's like, this is what I had done my entire life is, I do resistance training on these days. I do intense cardio these days. I do just like restorative work on these days. 

[00:34:36] And so, finally, after a particularly brutal workout session, I was like, I'm going to do this. I'm giving myself three months. I'm going to do a little mini experiment on myself three months, and I'm going to focus on heavy lifting and intense cardio during the first two weeks of my cycle, and then the last two weeks of my cycle, I'm going to do more things like taking walks, which I love doing anyway. I love going on walks and walking and yoga and doing those kinds of things. And I'll give myself three months. And then if the wheels totally come off, I'm going back to my old way of doing things. 

[00:35:05] And if things stay the same, that'll be great because then I think it'll be more in tune with my body. And I actually got stronger. And it was shocking to me because I felt like I was working out less. So, I was working out the same amount, but I was doing different things at different times. It was like I was just like heavy loading the resistance training during the first two weeks. I was more heavy loading, the restorative work during the last two weeks. And I actually was able to increase the amount of weight I was lifting, which is really huge for me because I hadn't increased in weight in years. I'd been trying to be stagnant. I'm hovering in a zone. And it got me stronger. 

[00:35:41] And so it was like one of those things that it took me a really long time to actually put it into practice in my own life. And then once I did, I was like, “Oh my gosh, why did it take me so long to believe this?” And it's because of it, it's been so ingrained, [Cynthia laughs] the idea that everything is the same for us all the time and that we need to follow this workout plan and we always need to be doing this and if you're not doing resistance training, and especially it's so funny right now in the perimenopause space because you have a lot of women who are still cycling, but then their hormones are starting to change and there's so much emphasis on resistance training during perimenopause, which I think is absolutely wonderful. 

[00:36:23] But like, if you're still cycling, I would say, “Yeah, but do something a little bit different during the second two weeks because you get less bang for your buck and then it just ends up for a lot of women like me just feeling like a real beat down.” [laughs] 

Cynthia Thurlow: [00:36:37] Yeah, no, I think it's such an important share. And thank you so much for sharing the power of the N of 1. I just did an AMA and I was talking about satellite cells and the role of estrogen and why HRT, if you're in menopause is so important. Certainly, like perimenopause, estrogen is 20 to 30% higher all over the place throughout perimenopause. But I agree with you that if you're still cycling, really tailoring your workouts to where you are in your cycle is so important. 

[00:37:06] And then on the other side, the flipside for women that are telling me I can't maintain muscle, I can't build muscle, and they're not on HRT, and it's like, if you understand physiologically, like the role of estrogen, as you astutely stated, it is a building hormone, it is an anabolic hormone. And when I was looking at the research about the satellite cells and stem cells and why estrogen's so important, like, actually there's little spots on the muscle where you can see as a cross section, like, this is exactly where the estrogen is stimulating the muscles to grow. So, again, so, so important, number one, if you're still cycling, time your workouts, especially strength training for when estrogen is highest, if you're in menopause and you're taking HRT, understanding that will help you with muscle building. I think that's really important. 

[00:37:53] One thing about progesterone that I think is really interesting is the role of progesterone and GABA. So, this is very, very important neurotransmitter, I think for a lot of individuals, they don't realize, like, I think about myself, I always use myself as the example, but as someone who probably had low progesterone my entire life, so perimenopause, for me, the symptoms of early perimenopause were a little more magnified and so understanding. Like, if you don't have enough circulating progesterone, you're not going to have enough GABA, which is going to impact anxiety, depression, a lot of those mood symptoms that we experience, I think for many of us, if it's not really severe, we tend to downplay it, but can be quite significant. 

Dr. Sarah Hill: [00:38:37] Yeah, it can. One of the things, I think that progesterone gets a bad rap because a lot of women, especially if they experience PMS, they're attributing the PMS symptoms to progesterone. And that's just not fair. Most of women's really bad experiences in terms of really bad PMS, but also in terms of really bad experiences postpartum and really bad experiences during perimenopause have to do with their lack of resilience to hormonal changes. And so, it's not about the progesterone per se. It's about their body's inability to adapt quickly to the hormonal changes. But progesterone itself actually does, as you noted. I mean, it's got a lot of these really beautiful properties in the brain that help to stabilize mood, which really surprises people.

[00:39:28] And this has to do with its impact on the GABAergic system in the brain. And so, just to give a little bit of background on this. When progesterone is being metabolized in the body, it causes the release of a neuroactive steroid that's called allopregnanolone. And allopregnanolone, one of the things that it's best known for, is that it is a potent stimulator of the GABA A receptors on neurons. And GABA is the chief inhibitory neurotransmitter pathway in the brain. And so, it's like the primary form of inhibitory neurotransmission that goes on in the brain. And inhibitory neurotransmission is the type of neurotransmission that calms our brain down. So, there's excitatory and then there's inhibitory. So, excitatory gets your neurons firing really quickly. And so, we get excitatory neurotransmission when we're angry or excited or we're feeling jumpy. 

[00:40:20] It's things that make us feel really alert and on top of things. And inhibitory neurotransmission is what goes on when we start to relax. And allopregnanolone, this metabolite of progesterone, which, again, is just something that naturally gets released as it's being broken down in the body. It stimulates these GABA receptors in the brain, and it actually calms the brain down. It slows it down. And this is part of the reason that we do feel a little bit sleepier during the second half of the cycle, is that we are feeling a little bit more relaxed because we have all of this GABAergic activity. 

[00:40:52] But this also makes it incredibly neuroprotective because one of the things that can get our brain in trouble is when it gets overexcited, it can actually cause damage to nerve cells when we have too much excitatory neurotransmission going on. And in fact, this is one of the reasons, and this is really fascinating, that progesterone is actually being used for treatment in traumatic brain injury. Because one of the things that happens in traumatic brain injury, is that you get excitotoxicity, which is where you get toxicity in the brain caused by overexcitement from too much stimulation. And so, they give people progesterone or they give them allopregnanolone directly. This calms the brain down. And it's actually very protective, given all of these really beautiful properties that it has and it also promotes things like my brain just, like, totally went off the rails there. 

[00:41:41] But it also helps to promote neuroplasticity was the word I was looking for. Helps to promote neuroplasticity in the brain. Given all these, like, really lovely properties that progesterone has, it's really wild to me because, again we talked about this bias toward estrogen. All of the research that's being done on sex hormones and Alzheimer's disease and sex hormones and any type of, you know, lack of cognitive decline and brain fog and everything is all looking at estrogen. And nothing is looking at progesterone. And in fact, sometimes when “progesterone” and I'm using finger quotes, if you're listening to this, instead of watching this, I'm using finger quotes for progesterone. They'll like, lump together studies that are looking at actually, micronized progesterone, so bioidentical progesterone, with studies that are used progestin, which is that synthetic progesterone that doesn't have these same properties. 

[00:42:38] And so just to talk to you for a moment on this, if I can. Progesterone, right in micronized progesterone that you can take in hormone therapy is biologically identical. When it gets broken down in the body, it causes the release of this beautiful allopregnanolone that has all these wonderful effects on the brain and calming effects on the brain. Progestin, which is the synthetic form of progesterone that's created by the drug companies that's put in hormonal birth control. It has none of these properties. So, progestins are mostly made out of testosterone. And so, when they get broken down in the body, they get broken down like testosterone. 

[00:43:16] And because of this, they don't release allopregnanolone. So, women who are using hormonal birth control have much lower levels of allopregnanolone relative to naturally cycling women. And so, it doesn't have these same properties. And so, if you look at the research literature, when it's looking at different types of hormone therapy on either the risk of Alzheimer's disease or the risk of cognitive decline or brain fog, if they actually include anything related to progesterone at all, they'll look usually at progestins and then they'll call it combined hormone therapy. As if women are taking micronized progesterone. And it's not the same thing. And it's not fair because when you look at the research, and in fact, there was just this study out, and I'm so angry about this. 

[00:44:01] So, there was a study that just came out and it got a lot of press last week, and it was about hormone therapy used at an early age is linked with an increased risk of breast cancer. Do you see that?-- [crosstalk] 

Cynthia Thurlow: [00:44:15] I do.

Dr. Sarah Hill: [00:44:15] Headlines for that. You go to this study, right? And some of the headlines actually said, “Estrogen used early in menopause linked with an increased risk of breast cancer.” And I'm like, “That doesn't sound right to me.” So, I went and I pulled up the actual paper and I read the research paper, and it was two groups of women, and these were women who were undergoing hormone therapy when they were like late 40s or 50s, and on hormone therapy looking at their breast cancer risk. 

[00:44:47] One group was taking estrogen and the other group was taking estrogen plus progestin. Again, not micronized progesterone, progestin. What they found was that women who were using estrogen only actually had a favorable profile for breast cancer risk. There was no increased risk. The women using estrogen plus progestin had an increased risk of breast cancer. And so now the takeaway message in some of the headlines, they're villainizing estrogen when estrogen wasn't the problem. In the estrogen only group, the women were doing great. So, they're villainizing estrogen in some of the headlines. The other headlines, and even the way that it's being written up in the press is talking about combined hormone therapy for women as if it's progesterone, when it's not. It's progestin, which is a Franken hormone. [Cynthia laughs] It's like, not a real-- Not a real hormone.

[00:45:43] So, it just makes me wild because people tend to villainize progesterone and there's been research, for example, some really beautiful work done by Jerilynn Prior. She's just a spitfire of a researcher, just so smart and just an absolute pioneer in terms of saying, like, “Hey, progesterone actually matters too. We have more than one sex hormone.” And she's done some really beautiful work looking at progesterone therapy for hot flashes. And what she finds is that it's just as effective as estrogen in minimizing hot flash symptoms for women who are in the menopausal transition. And nobody really hears about that. And the thing about it is that there are a lot of women who can't take estrogen because of different types of cardiovascular risk factors. 

[00:46:32] And so, they feel like they don't have any answers. And there's this really great research showing that progesterone, which is very safe, doesn't have any of the cardiovascular risk factors that estrogen does, is just as effective. And women are being given this information, and they're also not being given the information about, like, what do outcomes look like when you combine estrogen therapy with micronized progesterone, And stop lumping together research that includes micronized progesterone with that that includes progestins, or just looking at the combination estrogen and progestin and then calling that combined hormone therapy when it's really not. It's one hormone, estrogen, and then this Franken hormone, progestin, which doesn't do any of the positive things to women's bodies that progesterone does. 

Cynthia Thurlow: [00:47:26] There are so many amazing things that you just said. So, I want to make sure that we recap what you said. First and foremost, the role of progesterone with healthy neurogenesis, healthy brain physiology. I remind women all the time, even if you do not have a uterus, there are progesterone receptors throughout our bodies, just like estrogen, just like testosterone, and how important it is we're talking about brain health, that we not just focus myopically on estrogen being important for brain physiology. So that's number one. Number two, love, Jerilynn Prior. Actually, I have a graph of hers that Dr. Lara Briden superimposed that I'm using in my new book coming out next year, because it's so, so important to understand this physiology piece. And even most importantly, helping listeners understand that progestins are not akin biochemically physiologically to progesterone. 

[00:48:20] And why everyone should be asking for micronized progesterone is dirt cheap. It is, I want to say, the last time I checked, anywhere from $5 to $9 a month, very inexpensive. If you get fancy sustained release progesterone that's compounded, that is a little bit more expensive. And there are some of us that do need that. And I jokingly say someone will have to pry progesterone out of my cold dead hands because I think it is so helpful for a multiplicity of reasons, but helping people understand that within the media, I have to believe it's well meaning. I have to believe that not everyone wants to create clickbait junk that we click on and we're like, “What are they talking about?” That somehow, it's harmful to be on combined bioidentical hormone replacement therapy when you find out it actually isn't bioidentical, it's synthetic and I'm going to use your term, and I will borrow and give you credit for this Franken hormone of progestin, which is not identical, does not have the same properties, does not act the same physiologically in our bodies.

[00:49:23] And I think this explains a lot that there's just a lot of, I trained during the WHI timeframe, so Women's Health Initiative and I was neatly tucked away in cardiology. So, we saw hundreds, if not thousands of patients who were on HRT doing well on HRT, taken off their HRT. And it's like a whole generation of clinicians and patients who feared hormones, who were afraid to talk about hormones. So, I'm so glad that, we're coming back around and having these conversations to dispel the myths and also be very clear about synthetic versus bioidentical hormones and how they do make a big difference when we're talking about health, longevity, brain health, etc. 

Dr. Sarah Hill: [00:50:05] Yeah, I mean with the brain health, certainly. And then even from the neck down too, with the cancer risk, for example, it's like you do get this increased cancer risk with these funky progestins because it's being broken down like testosterone in the body which is carcinogenic for lack of a better word. And progesterone does the opposite, instead of being associated with cell proliferation, which when you get a lot of cell proliferation that obviously is something that's associated with increased cancer risk. It leads to instead cell differentiation. So, it's like slowing down cell proliferation and causing the cells to mature and differentiate. And so, it has all of these different types of effects in the body and there's so much confusion over it. 

[00:50:50] And I think that's another part of this, you know, puzzle of like why is it that we've ignored and even villainized progesterone when it is this really lovely hormone that-- it causes us to experience a different version of ourselves. So, for those of us who are cycling, right, it's like it does cause us to experience a different version of ourselves. And it's not as sexy and fun as estrogen self. Like the all-day dance party where [Cynthia laughs] you feel really sexy and you're just like really interested in sex and music and pleasure. But instead, I mean it has its own set of strengths. It's more about like connection and inward facing energy and rest and all of these things matter and they're really important. 

[00:51:36] And certainly, the physical benefits of actual progesterone in terms of the things that it does outside of the brain with its impact on increasing bone strength. So, we always think about estrogen as being the hormone that prevents osteoporosis. But progesterone, again, always ignored but just as important [Cynthia laughs] because it also plays a role there, really important with brain health. I'm really hopeful that in the next 15 to 20 years that we really start to see the conversation around cognitive decline in Alzheimer's disease to also include a discussion of progesterone. Because the fact is I can't imagine a universe in which it wouldn't be protective because of. It's really great, it has these great impacts on neuroplasticity. It also anti-inflammatory. I think that there's a lot that it probably can do that's protective and that the singular focus on estrogen only, which again, you know, I love estrogen and I think it's incredibly important, but it's just not the only player. And I think that we have a lot to learn. 

Cynthia Thurlow: [00:52:42] Absolutely. And for those, if they're listening, if they're someone that has severe PMS or PMDD and for listeners, PMDD I think is less than 5% of women. So, it's a very small but very significant, if they experience it. What's the research suggesting? Is it that they're just simply more sensitive to those fluctuations in hormones? You were touching on this earlier. But there's always questions that come in around this, like what is happening to my body that makes my symptoms worse than like my five best friends?

Dr. Sarah Hill: [00:53:16] So, the answer to that seems to be very complex. And so, the research on it is approaching it in a couple of different angles. And I'll just tell you, because there's no singular research consensus on what some of the primary risk factors are. But we'll just talk about gene-based factors and we know that there is a genetic component to this in that women who have really severe PMS and PMDD also tend to have relatives who have severe PMS and PMDD. And there's a couple of different SNPs, little snippets of genetic variability that people share with their relatives that are being explored as things that are potential risk factors for developing PMD. So, so one thing we know that there's a familial contribution. 

[00:54:00] Another thing that we know is that many women who experience PMDD and severe PMS have experienced some form of trauma in their lives. And so, it seems that the functioning of the HPA axis, which again is the brain sort of stress axis in the body that regulates the release of the stress hormone cortisol. Many women who experience PMDD have dysregulation of their stress response. And a lot of them, like I said, there's a greater than as you would predict probability. If you're somebody who has PMDD, the probability that you've experienced trauma is significantly greater than what it is for somebody who's a non-sufferer. And it does seem that ability of your stress response to be able to regulate appropriately in response to stressful situations is also a contributing factor.

[00:54:48] And what's really nice about that is, I mean it's not obviously there's nothing good about trauma, but rather what's good about being able to identify that. So, if you're somebody who's listening and you're experiencing, and let me just say this really quickly before I dive too deeply in that, and that is to say that hormonal transition points are pain points for women and women who experience these as pain points. So, if you had a difficult puberty, chances are you're going to have a difficult pregnancy, chances are you’ll have a difficult postpartum Chances are you're going to have a difficult luteal phase like your PMS, and PMDD's going to be bad. And chances are you're going to have a difficult Iraqi perimenopause menopausal transition. 

[00:55:24] So, women who are sensitive to hormonal changes, unfortunately tend to get it upside the head every time that they're experiencing a big set of hormonal changes. And so, these principles that we're talking about here are things that can apply also to improving the perimenopausal experience. Women who experience trauma tend to have a worse perimenopausal experience. They tend to have a greater probability of PMDD. And what's great about understanding this, if you're somebody who's experienced trauma or this might describe you, is that anything that you can do to help increase your body's ability to adaptively respond to stress are things that are actually going to really help you. And one of the things about that I'm most excited about with this is what's going on right now with research to try to improve vagal tone. 

[00:56:15] So, I'm sure that your listeners are probably familiar with the vagus nerve, but this is the big nerve that travels throughout your body. The word vagus is actually, I forget what the Greek word, but it means wandering nerve because it's essentially this nerve that branches out into all systems of your periphery. And it's essentially your brain's eyes and ears on every single system in the body. It's just like keeping, got its ear to the door, kind of listening for trouble and seeing what's going on in the fingertips and like, “Okay, what's going on in the stomach right now?” And it's how your brain keeps track of what's going on. 

[00:56:47] And when you have a really nicely adaptive, like what we call having high vagal tone, it means that your body is able to quickly pick up on stressors, react to them, and then quickly calm itself down. And this is something that we know to be lacking in people who have dysregulation in their HPA axis. So, if you're somebody who experienced trauma, for example, you probably have lower vagal tone than somebody who has not experienced trauma. And it appears that vagal tone is something that probably impacts people's responses to hormonal changes, and that includes across the cycle and then also across the perimenopausal experience. And there are some really great research being done now looking at stimulating the vagus nerve as a means of trying to increase vagal tone. 

[00:57:31] And this is stuff like you can even get things to stimulate your vagus nerve on your own. Like, they've got these little vibrating devices that you can stick, like, put on your collarbone and other places. Chewing gum actually stimulates your vagus. 

Cynthia Thurlow: [00:57:43] Interesting.

Dr. Sarah Hill: [00:57:44] Yeah, yeah. So, it's something that can stimulate your vagus nerve. You can increase vagal tone by doing things like practicing meditation, which I highly recommend and this is actually appears to be the mechanism behind the use of meditation, for example, to improve perimenopause and PMDD and severe PMS. Because women will hear this and they'll hear “Meditate. [Cynthia laughs] Like, how is meditating going to help me get rid of a hot flash?” Well, it turns out that there's these really great randomized trials that they've done where they'll randomly assign people to do things like meditate or not. And they do see improvements in PMDD and severe PMS. 

[00:58:21] And it appears that this is operating through increases in vagal tone. And so, improvements in vagal tone. And so, for women who are going through perimenopause, this is also something that can be really useful, is anything that you can do to try to increase your body's resilience to stress is going to improve your experiences that way. Another contributing factor to PMDD is having dysregulated stress response. Inflammation is another big one, and inflammation is the whipping boy, like, of everything. And it's like, we always know if there's something going on in the body that's not supposed to be happening. 

Cynthia Thurlow: [00:59:00] You're inflamed. 

Dr. Sarah Hill: [00:59:01] Yeah, exactly. It's like, you can almost bet that inflammation is going to be a contributing factor. And this is no exception into that. Inflammation also decreases your resilience to hormonal changes because it decreases cellular plasticity. And it really requires, when you think about when your hormones are rising and falling, and especially when they're falling, it's like, here's progesterone, this hormone that causes the release of allopregnanolone, which is really calming. And so, your body's releasing this, and your body's like, “Oh, I love this.” And so, it sprouts all these new receptors for being able to transmit allopregnanolone so we can get all this GABAergic activity. 

[00:59:41] It's got all these little receptors that are out there, and then all of a sudden it starts to fall and you've got all these naked receptors and they're like, “Where to go, like where to go?” And the way that we're able to feel better quickly is by having these things retreat where we're not experiencing something that feels like withdrawal. And when you have a lot of cellular plasticity, your body does this pretty seamlessly and you're able to wax and wane through hormonal changes. And I talk about this, in The Period Brain, which is my new book. I talk a lot about ways that we can improve our cellular plasticity and improve our resilience to hormonal changes. 

[01:00:17] Because a lot of times our negative experiences around times of hormonal transition are due to a lack of resilience to these sorts of changes. And so, anything we can do to decrease inflammation, which of course includes the usual suspects like getting enough sleep and getting regular sunlight and eating a clean diet and trying to manage stress, because we know stress is inflammatory. All of these things are going to improve symptoms of things like PMS and PMDD, but also improve the experience in perimenopause. 

Cynthia Thurlow: [01:00:52] Such an important conversation. And, and certainly it always goes back to basics, like on any level. It's those firm foundational lifestyle principles that always are going to work in our favor. I so have loved this conversation, Dr. Hill. Please let listeners know how to connect to the outside of this podcast, how to get access to your newest book, or learn more about your work. 

Dr. Sarah Hill: [01:01:12] Yeah, they can find me on social media and I'm on all platforms, but most active on Instagram. And my handle is @sarahehillphd. So that's Sarah with an H, @sarahehillphd. And so, you can find me on Instagram. And like I said, I'm on all channels. I'm not as active on the others. [Cynthia laughs] And you can find me online at sarahehill.com and you can find my new book, The Period Brain: The New Science of why We PMS and How to Fix It. And it's going to be on sale at the end of September and it's available now for preorder. 

Cynthia Thurlow: [01:01:46] Awesome. Thank you again for your time. 

Dr. Sarah Hill: [01:01:48] Thank you. 

Cynthia Thurlow: [01:01:51] If you love this podcast episode, please leave a rating and review. Subscribe and tell a friend. 

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