Four of the world's leading female health doctors are now publicly saying the same thing: Your cycle provides the most honest health data your body produces every month. And almost no one has taught you how to read it.
In October 2025, four of the most renowned researchers in women's health sat together on The Diary of a CEO and voiced what most of their patients were never told. Dr. Mary Claire Haver, Dr. Vonda Wright, Dr. Stacy Sims, and Dr. Natalie Crawford spent hours dismantling the notion that heavy periods, worsening PMS, and the chaos of perimenopause are something women simply have to put up with.
They discussed endometriosis, PCOS, hormonal decline, the dramatically rare use of hormone therapies, and how consistently the medical system fails to take the female cycle seriously for what it is: a diagnostic tool.
The central argument permeated everything they said. It's the same point Andrew Huberman and Dr. Haver repeatedly returned to in their episode on the Huberman Lab: the menstrual cycle is not just a reproductive function. It is a biological report card. Every month, it shows what's happening throughout your entire physiology.
If this report card is bad, it's not normal. It's information. And the difference between managing symptoms and understanding their cause is the difference between another decade of struggling through the second half of the month and actually dealing with what the data is telling you.
What doctors say and most women have never heard
Dr. Vonda Wright was clear about the timeframe that many doctors still fail to communicate: Perimenopause can begin as early as 35, even in women with perfectly regular cycles.
The symptoms of this phase—disrupted sleep, brain fog, heart palpitations, mood swings, and cognitive changes—are often dismissed or attributed to stress, anxiety, or lifestyle. Wright and Haver both described how high-performing women came to their practices seriously concerned after other doctors had told them everything was normal. The values were normal. The woman was not.
Dr. Haver calls this phase the "zone of chaos." Estrogen and progesterone begin to fluctuate unpredictably years before actual menopause. Menopause occurs on average between 51 and 52 years of age. The transition before it can last for an entire decade. During this time, the hormonal situation becomes increasingly unstable, and most women receive no guidance on what is happening or what they can do.
Haver referred to hormone therapy on the Huberman Lab as the most effective measure to manage this transition. Nevertheless, only 4% of eligible women in the USA use approved hormone therapy, mainly because no one has told them this option exists or because the conversation about it has never taken place.
Why severe period pain is never simply part of the deal
Dr. Natalie Crawford addressed a topic that came up repeatedly in the episode: the normalization of severe menstrual pain.
Crawford pointed out that up to 50% of patients with unexplained infertility may have endometriosis, a condition where tissue similar to the lining of the uterus grows outside the uterus, causing inflammation, scarring, and adhesion of organs.
It typically takes six to ten years to diagnose endometriosis because the pain it causes is so consistently dismissed as normal. Women are given birth control pills for symptom control instead of an investigation into the cause. Thus, the disease progresses for years while being inadequately treated.
Crawford's position was clear: Extreme period pain is not normal. It is a signal that needs to be investigated, not suppressed.
The same applies to irregular cycles, spotting before the period, and cycles that worsen year after year. These are not peculiarities or stress reactions. They are biological signals from a system that wants to communicate something that no one has yet picked up on.
Symptoms of perimenopause can begin as early as 35 and include sleep disturbances, psychological distress, and cognitive difficulties. Nevertheless, these symptoms are routinely dismissed or attributed to other causes, instead of being recognized as part of a hormonal transition that deserves attention and treatment.
— Dr. Vonda Wright & Dr. Mary Claire Haver
What a healthy cycle actually looks like
A healthy menstrual cycle lasts between 25 and 30 days. The period itself lasts three to seven days, with moderate, predominantly red bleeding during the first two to three days. Pain is minimal.
The luteal phase, the two weeks between ovulation and the start of the next period, brings no significant drops in mood, no energy crashes, and no sleep disturbances.
PMS, in the form most women experience it—the week before the period that disrupts daily life, disturbs sleep, and destabilizes mood—is not necessarily a given. It is a sign that the hormonal situation in the luteal phase is not functioning as it should.
At this point, Dr. Stacy Sims went further than most researchers. Women need to understand their cycle as a source of data that affects all areas of female physiology—not just reproduction.
The luteal phase changes metabolism. It affects glycogen storage. It alters the stress response. And it shifts how the body recovers from physical exertion.
Wearables that do not consider where a woman is in her cycle provide misleading data. Training plans without cycle consideration lead to poorer results. The cycle is not a monthly inconvenience. It is the operating system of the female body. Treating it as background noise costs women their health—in a way that is only now being properly named.
The cellular explanation that rarely reaches doctors
The hormonal discussion: estrogen, progesterone, the ratio between the two, is where most medical conversations about cycle health end. What longevity research adds is the level below: the cellular.
The enzyme that produces progesterone is called 3β-hydroxysteroid dehydrogenase. It needs NAD⁺ as a cofactor to function. This means that progesterone production is not just a hormonal event, but also a cellular one. And it depends on enough NAD⁺ being available at the enzymatic level.
As NAD⁺ levels decline in the 30s, the cells that produce progesterone become increasingly less efficient. Thus, the luteal phase becomes harder not only because of hormonal shifts, but also because the cellular machinery behind these hormones runs out of its most important fuel.
NAD⁺ is also needed for sirtuins, which regulate the inflammatory response in uterine tissue. Inflammation determines the intensity of cramps and menstrual pain. If enough NAD⁺ is present, sirtuins help dampen this response during menstruation. If NAD⁺ levels are low, this regulation functions less well, and the inflammatory signal is stronger than necessary.
This is part of the explanation why period pain often gets worse with age instead of better—the opposite of what many women are led to expect.
On the Huberman Lab, Dr. Haver described the loss of estrogen as something that accelerates a woman's path towards cardiometabolic diseases, cognitive decline, and early death. She was explicit: the longer a woman's body has to cope without estrogen, the higher these risk factors become.
What longevity research adds here is the parallel decline of NAD⁺. It occurs in the same decade that estrogen and progesterone become unstable. The two processes are not separate. They influence each other. The NAD⁺ decline weakens the cellular energy environment on which hormone production depends. Therefore, the hormonal shift of perimenopause hits harder when it encounters a cellular energy deficit.
Restoring NAD⁺ through NMN does not replace declining hormones. And it is not a substitute for hormone therapy where medically indicated.
What it does achieve is something different: it restores the cellular conditions under which hormone production and hormone regulation take place. The enzymatic efficiency behind progesterone production. The sirtuin activity that dampens inflammation. And the mitochondrial function that gives the luteal phase the cellular resources it needs not to collapse.
The most significant improvements in their cycles are reported by women who have consistently taken NMN over several cycles. Because the effect follows the pace of a cycle, not that of a day.
What you should track and why it matters
Dr. Sims' argument was: women should compare their physical data across identical phases of consecutive cycles, rather than viewing each cycle as a single event. The pattern over months is the signal.
A luteal phase that consistently deteriorates over six months indicates something different than a single difficult month. A cycle that gradually becomes longer or gradually shorter indicates a change in the hormonal situation, and this deserves attention before it becomes a problem requiring greater intervention.
Tracking four things consistently is sufficient for this: the cycle length from day one to day one of the next period, the intensity and color of the bleeding, the symptoms of the luteal phase regarding mood, energy, sleep, and pain, as well as all symptoms around ovulation.
After three to six months, this creates a data picture that no single doctor's appointment can provide. This picture is your report card. Reading it is not complicated. And what it tells you about where to direct your attention is worth more than any general advice to eat less, reduce stress, or simply wait and see.
Four of the most respected female health doctors worldwide spent hours on one of the most listened-to podcasts explaining that the symptoms most women accept as normal are not normal.
The cycle is a report card. The period is information. The luteal phase is a window into the cellular and hormonal conditions of the entire system. What you do with this data is your decision. But you cannot react to information no one has ever given you—and no one has ever given you this information.
Sources
- Haver, M. C., Wright, V., Sims, S., & Crawford, N. (2025, October 16). Hormone & fertility experts: We've been lied to about women's health. The Diary of a CEO with Steven Bartlett.
- Haver, M. C. (2024, June 3). How to navigate menopause & perimenopause for maximum health & vitality. Huberman Lab Podcast with Andrew Huberman. https://www.hubermanlab.com/episode/dr-mary-claire-haver-how-to-navigate-menopause-perimenopause-for-maximum-health-vitality
- Cherradi, N., Defaye, G., & Chambaz, E. M. (2014). Mitochondrial 3β-hydroxysteroid dehydrogenase and NAD+ cofactor dependence. Journal of Biological Chemistry. https://doi.org/10.1074/jbc.M111.292490
- Covarrubias, A. J., Perrone, R., Grozio, A., & Verdin, E. (2021). NAD+ metabolism and its roles in cellular processes during ageing. Nature Reviews Molecular Cell Biology, 22(2), 119–141. https://doi.org/10.1038/s41580-020-00313-x
- Yoshino, M., Yoshino, J., Kayser, B. D., et al. (2021). Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women. Science, 372(6547), 1224–1229. https://doi.org/10.1126/science.abe9985
- Imai, S. I., & Guarente, L. (2014). NAD+ and sirtuins in aging and disease. Trends in Cell Biology, 24(8), 464–471. https://doi.org/10.1016/j.tcb.2014.04.002
- Massudi, H., Grant, R., Braidy, N., et al. (2012). Age-associated changes in oxidative stress and NAD+ metabolism in human tissue. PLOS ONE, 7(7), e42357. https://doi.org/10.1371/journal.pone.0042357