Four of the world's leading women's 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 taught you how to read it.
In October 2025, four of the most renowned researchers in the field of women's health sat down together on The Diary of a CEO and spoke the truth that most of their patients had never been told. Dr. Mary Claire Haver, Dr. Vonda Wright, Dr. Stacy Sims, and Dr. Natalie Crawford spent hours dismantling the idea that heavy periods, worsening PMS, and the chaos of perimenopause are something women just have to accept.
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 as what it is: a diagnostic tool.
The central argument ran through everything they said. It is the same one that Andrew Huberman and Dr. Haver kept returning 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 is happening throughout your entire physiology.
If this report card is poor, it is not normal. It is information. And the difference between managing symptoms and understanding their root cause is the difference between another decade of gritting your teeth through the second half of the month and actually dealing with what the data is telling you.
What the doctors are saying that most women have never heard
Dr. Vonda Wright was clear regarding the timeline that many doctors still do not convey: perimenopause can begin as early as age 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 frequently dismissed or blamed on stress, anxiety, or lifestyle. Both Wright and Haver described how high-performing women came into their practices deeply concerned after other doctors had told them that everything was fine. The lab 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 ages 51 and 52. The transition before it can drag on 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.
On the Huberman Lab, Haver described hormone therapy as the most effective intervention for managing this transition. Nevertheless, only 4% of eligible women in the US use FDA-approved hormone therapy—largely because no one told them the option existed or because the conversation was never had.
Why severe period pain is never "just part of it"
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. In this condition, tissue similar to the uterine lining grows outside the uterus, causing inflammation, scarring, and organ adhesions.
It typically takes six to ten years to receive an endometriosis diagnosis. The reason: the pain it causes is so consistently dismissed as normal. Women are given the pill for symptom control instead of an investigation into the cause. Thus, the disease progresses over years while being inadequately treated.
Crawford's position was clear: extreme period pain is not normal. It is a signal that should be investigated, not suppressed.
The same applies to irregular cycles, spotting before your period, and cycles that worsen year after year. These are not quirks and they are not stress reactions. They are biological signals from a system trying to communicate something that no one has picked up on yet.
Symptoms of perimenopause can begin as early as age 35 and include sleep disturbances, psychological distress, and cognitive difficulties. Despite this, these symptoms are routinely dismissed or attributed to other causes, rather than 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 a moderate, predominantly red flow 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—should not bring significant mood crashes, energy collapses, or sleep disruptions.
PMS, in the form most women experience it—the week before the period that disrupts daily life, interferes with sleep, and destabilizes mood—is not inherently part of it. It is a sign that the hormonal landscape in the luteal phase is not functioning as it should.
Dr. Stacy Sims went further here than most researchers. Women must understand their cycle as a data source that affects all areas of female physiology—not just reproduction.
The luteal phase alters metabolism. It influences glycogen storage. It changes the stress response. And it shifts how the body recovers from physical exertion.
Wearables that do not account for where a woman is in her cycle provide misleading data. Training plans without cycle awareness 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 identified.
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 layer beneath: the cellular level.
The enzyme that produces progesterone is called 3β-hydroxysteroid dehydrogenase. It requires NAD⁺ as a cofactor to function. This means progesterone production is not only a hormonal event but also a cellular one. And it depends on having enough NAD⁺ available at the enzymatic level.
If NAD⁺ levels drop during your 30s, the cells that produce progesterone work less and less efficiently. Therefore, the luteal phase becomes harder not only because of hormonal shifts, but also because the cellular apparatus behind these hormones is running out of its most important fuel.
NAD⁺ is also needed for sirtuins, which regulate the inflammatory response in uterine tissue. Inflammation determines the severity of cramps and period pain. If enough NAD⁺ is present, sirtuins help dampen this reaction during menstruation. If NAD⁺ levels are low, this regulation works less effectively, and the inflammatory signal becomes stronger than necessary.
This is part of the explanation for why period pain often gets worse instead of better with age—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 toward cardiometabolic disease, cognitive decline, and early death. She was explicit: the longer a woman’s body has to go 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 in which estrogen and progesterone become unstable. The two processes are not separate. They influence each other. The decline in NAD⁺ weakens the cellular energy environment upon which hormone production depends. This is why the hormonal transition of perimenopause hits harder when it meets a lack of cellular energy.
Restoring NAD⁺ via NMN does not replace declining hormones. And it is not a substitute for hormone therapy where medically indicated.
What it does is different: it restores the cellular conditions under which hormone production and regulation occur. 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 to not collapse.
The most significant improvements to their cycle are reported by women who have consistently taken NMN over several cycles. Because the effect follows the tempo of a cycle, not the tempo of a single day.
What you should track and why it counts
Dr. Sims' argument was that women should compare their physical data across identical phases of consecutive cycles, rather than treating every cycle as an isolated event. The pattern over months is the signal.
A luteal phase that consistently worsens over six months says something different than a single difficult month. A cycle that gradually becomes longer or shorter indicates a shift in the hormonal landscape, and that deserves attention before it becomes a problem requiring major interventions.
Consistently tracking four things is enough for this: cycle length from day one to day one of the next period, flow and color of the bleeding, luteal phase symptoms regarding mood, energy, sleep, and pain, as well as any symptoms around ovulation.
After three to six months, this results in 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 focus your attention is worth more than any general advice to eat less, reduce stress, or "just wait and see."
Four of the most respected women's health doctors in the world 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 you were never given—and no one has ever given you this.
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