Women live longer on average than men. However, they also spend 25% more of their lives in poor health—nine years more. And for the most part, this occurs during their working years, not in old age. Here, you will learn what this number means, what lies behind it, and what research has to say about how this can be changed.
The figure that has defined the debate on women's health since its publication at the World Economic Forum in Davos in January 2024 is this: Women spend 25% more of their lives in poor health than men.
The study was conducted by the McKinsey Health Institute in collaboration with the World Economic Forum. It was the first time that the extent of the so-called gender health gap was quantified globally and with such precision.
Women live longer on average than men. For a long time, this was considered proof that women are healthier or that the healthcare system is adequately providing for them. The 25% figure completely dismantles this assumption.
Living longer is not the same as living well. Women spend a disproportionate part of their longer lives in poor health, with limitations and chronic suffering that the healthcare system has consistently failed to prevent, recognize, or treat.
This gap corresponds to 75 million years of life lost every year due to poor health or early death. Closing it would give every woman in the world seven additional healthy days per year—calculated over a lifetime, more than 500 days. And it would allow the global economy to grow by over a trillion dollars annually by 2040.
These are not wishful projections. They are the documented economic costs of what is already happening, measured in healthy years of life that women do not receive.
Nine years, most of it during working age
The average woman spends nine years more than the average man in poor health or with some form of limitation.
This figure becomes most poignant through another finding: About half of the healthy years that women lose occur between the ages of 20 and 60.
This is not illness in old age. This is chronic suffering during the very decades in which women are building careers, raising families, running companies, and making the majority of healthcare decisions for everyone around them. The years of highest performance, greatest goals, and most responsibility are being lost.
The conditions behind this are neither rare nor biologically mysterious. They are conditions that affect hundreds of millions of women, have been documented for decades, and have received only a fraction of the research funding that would correspond to their prevalence.
PMS, endometriosis, menopause, migraines, conditions related to pregnancy and childbirth, as well as cardiovascular diseases in women: these nine conditions alone account for a third of the total health gap.
PMS and menopause combined—conditions that affect virtually every woman who reaches midlife—received less than 1% of the research funding allocated to the conditions behind this gap between 2019 and 2023.
What the doctors said when they finally got a big stage
In October 2025, the episode of The Diary of a CEO featuring Dr. Mary Claire Haver, Dr. Vonda Wright, Dr. Stacy Sims, and Dr. Natalie Crawford became one of the most shared conversations on women's health that the media has ever produced.
What these doctors described was not a new discovery. It was a long-documented reality that was finally articulated on a stage large enough to reach those affected.
Women come to the clinic with serious symptoms and are told it is stress, anxiety, or simply part of being a woman. Women with endometriosis wait an average of six to ten years for a diagnosis because their pain is normalized instead of investigated. And women in perimenopause enter one of the most physically profound transitions of their lives—without preparation and without support, because the medical system never developed suitable tools for this phase.
Dr. Wright described this using the term "Whiny Woman Syndrome." This refers to the well-documented pattern of attributing women's symptoms to emotional rather than biological causes. The result is delayed diagnoses, inadequately treated pain, and years of suffering that could have been addressed earlier if the symptoms had been taken as seriously as those of a male patient.
This is not a fringe observation. It is a pattern so well-attested that it has a name. And women who have experienced it immediately recognize the description.
Women with very serious illnesses lose themselves in the healthcare system for years. Sometimes they are told it is all in their heads, while in truth they are severely ill.
The three causes identified by the WEF and McKinsey
The report from the McKinsey Health Institute identifies three structural causes for the health gap that apply across all conditions and global regions.
The first is a gap in science itself. Female biology is under-researched, women have historically been underrepresented in clinical trials, and the data foundation for treatment decisions relies disproportionately on male data.
The second is a gap in care. Even where knowledge exists, it is not consistently applied. Women face greater hurdles in accessing treatment, and their symptoms are more frequently dismissed or inadequately treated.
The third is a gap in data. There are fewer standardized measurement tools for conditions that affect women. They are less frequently included in large epidemiological studies. And therefore, the evidence that would trigger investment and policy change is less likely to emerge.
These three gaps reinforce one another. Insufficient science produces insufficient care. Insufficient care produces insufficient data. And insufficient data provides no arguments for better science.
This cycle has been running for decades. Its result is the 25% figure: 25% more life spent in poor health from conditions that would be preventable or treatable, or at least better understood than the current system has allowed.
The cellular level, which barely appears in the debate
The public discussion about the health gap revolves primarily around research funding, clinical bias, and the absence of women in studies. All of this is real and important.
What almost never appears is the cellular level: the fact that the fundamental biological processes that maintain women's health receive less and less support with age, specifically due to the decline of NAD⁺.
NAD⁺ is behind energy production, DNA repair, hormone production, sleep regulation, immune function, and inflammation control. In every adult, its levels drop from the mid-20s onwards. By middle age, it is only at about half of its peak.
In women, this decline runs parallel to the hormonal changes of perimenopause and menopause. Both processes intensify their impact on health and performance.
The enzyme that produces progesterone requires NAD⁺ as a cofactor. Sirtuins, which regulate inflammation, need NAD⁺ for activation. And the mitochondria, which supply energy to the cells of all those tissues that change during menopause, need NAD⁺ to produce energy efficiently.
The cellular energy deficit caused by the decline in NAD⁺ should not be viewed separately from the health gap. It is one of the biological mechanisms underlying it, and it acts at a level that most clinical debates about women's health have never looked at.
The women's health gap is a failure of research and a failure of funding. But it is also a failure of cellular energy supply, and policy alone will not solve that.
What it would take to close the gap
The action plan published by McKinsey and the World Economic Forum in January 2025 specifies what would be structurally necessary: more research specifically on female biology, better data disaggregated by sex, clinical guidelines that reflect the female progression of disease, and investments directed where the disease burden is highest and research funding has been lowest so far.
The Gates Foundation has pledged $2.5 billion toward this by 2030. The World Economic Forum has founded the Global Alliance for Women's Health with over 120 member organizations. And every dollar invested in women's health is estimated to bring back around three dollars in economic growth.
On an individual level, closing the gap means women getting access to information about their own biology that the current system has not reliably provided them. This includes the cellular mechanisms behind their ailments, the existing research on them, and products that were actually developed with their biology as the foundation, rather than as an afterthought.
NMN is one of the few longevity interventions whose fundamental human study was specifically conducted with women and measured results that are directly relevant to female metabolic health.
This precision is not the norm. It is what it concretely means to take biology seriously. And it is the minimum standard that women have always deserved.
The seven days that matter
Closing the health gap would give every woman in the world seven additional healthy days per year. Taken by itself, that sounds like little. Calculated over a lifetime, it is 500 days. And across 3.9 billion women, it is 75 million healthy life years that would be regained every year—for conditions that are already understood, already partially treatable, and permanently underfunded.
The 25% figure is not a law of nature. It is the documented price of decisions that a healthcare system and a research industry have made over decades. And it can be reversed by making different decisions. The momentum for this—in funding, in research, in public debate—has never been greater than now.
Women live longer. But they also spend more of those years in poor health than they have to, and they lose the most productive decades of their lives to conditions that were never sufficiently researched, never sufficiently funded, and never taken seriously enough.
That is the 25% figure. A number that should not exist and that a growing international alliance of researchers, doctors, and institutions is now trying to change. The question for every woman reading this is what she does in the meantime, while the system catches up to the biology it has overlooked for so long.
Sources
- McKinsey Health Institute & World Economic Forum. (2024). Closing the women's health gap: A $1 trillion opportunity to improve lives and economies. https://www.mckinsey.com/mhi/our-insights/closing-the-womens-health-gap-a-1-trillion-dollar-opportunity-to-improve-lives-and-economies
- McKinsey Health Institute & World Economic Forum. (2025). Blueprint to close the women's health gap: How to improve lives and economies for all. https://www.mckinsey.com/mhi/our-insights/blueprint-to-close-the-womens-health-gap
- McKinsey Health Institute. (2024, 30. Januar). MHI unveils investment case for closing the women's health gap. https://www.mckinsey.com/about-us/new-at-mckinsey-blog/mhi-unveils-investment-case-for-closing-the-womens-health-gap
- Gates Foundation. (2025). Gates Foundation announces catalytic funding for women-centered research. https://www.gatesfoundation.org/ideas/media-center/press-releases/2025/08/womens-health-funding-commitment
- Haver, M. C., Wright, V., Sims, S., & Crawford, N. (2025, 16. Oktober). Hormone & fertility experts: We've been lied to about women's health. The Diary of a CEO with Steven Bartlett.
- World Economic Forum. (2025, Januar). There's a women's health gap: Here's how to close it. https://www.weforum.org/stories/2025/01/theres-a-womens-health-gap-heres-how-to-close-it/
- 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
- 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.