Research identifies a single molecule as central to energy production, sleep regulation, hormone synthesis, hair follicle metabolism, and cognitive function. It has been declining since your mid-20s, and this is what happens when you restore it.
NAD+ powers over 500 functions in the human body. Energy production, DNA repair, sleep regulation, hormonal balance, immune function, brain performance. Every single one of these depends on having enough NAD+ in your cells. And it has been dropping since your mid-20s. By the time most women are in their 50s, they are running on less than half of what they had at 20. No one tells you this. Your doctor doesn't test for it. And the symptoms it causes are dismissed as stress, aging, or simply being a woman.
NMN is the most well-researched way to restore NAD+. What follows is what research and reported experiences document in five areas.
Energy and Recovery
When NAD+ drops, mitochondria produce energy less efficiently, and that is the entire explanation for the afternoon slump, slow recovery, and the feeling of running at reduced capacity, no matter how much you sleep. It isn't stress and it isn't a discipline problem. It is a cellular deficiency, and coffee does not fix a cellular deficiency.
Women who have taken NMN consistently report not a dramatic boost in the first two to four weeks, but more stable energy. Some describe the afternoon slump as less pronounced, recovery between demanding days as faster, and energy as more evenly distributed throughout the day. These are individual reports, and results vary.
Sleep
Sleep is one of the first changes reported by women who take NMN consistently – often as early as the first week. Some describe sleep as deeper and mornings as more restful. These are individual reports, and results vary. The reason is biological and direct: research identifies NAD+ as a regulator of SIRT1, the protein that controls the internal clock. Studies document that the internal timing system that controls sleep architecture loses precision when NAD+ levels drop. Research links NAD+ to SIRT1 regulation of the internal clock. The hypothesis is that the restoration of NAD+ could support the biological conditions involved in sleep architecture, rather than producing a sedative effect.
Hormonal Health and the Cycle
The enzyme that produces progesterone cannot function without NAD+ as a cofactor, meaning that progesterone production is not just a hormonal matter, but a cellular one. Research documents that the enzymatic systems involved in the regulation of the menstrual cycle – including progesterone synthesis – become less efficient at the cellular level when NAD+ drops.
The luteal phase is already the most energy-intensive week of the month because metabolism increases, body temperature rises, and your hormones require more cellular resources to stay in balance. When NAD+ is low, research suggests that the body may not have sufficient NAD+ to efficiently meet the increased cellular demands of the luteal phase. Most women are told these symptoms are just PMS. Research shows that there is a cellular energy dimension that has been largely missing from this conversation so far.
Brain and Focus
The brain consumes 20% of total body energy, even though it only accounts for 2% of body weight, making it one of the first places where the NAD+ decline becomes noticeable, and one of the last places women look for an explanation. The fog, the slower processing, the decision that takes twice as long as it used to, the diminished emotional regulation, and sometimes even the feeling of being more irritable than ever before.
Research suggests that these may not be inevitable signs of aging, but rather signs of a dwindling supply of cellular fuel affecting neurological function. Women reporting on their experiences after consistent NMN use do not describe a dramatic transformation, but a gradual return to a baseline state they had attributed to aging, especially if they are accustomed to demanding schedules and intense daily structures.
Hair, Skin, and Body
Hair follicles are among the most metabolically active cells in the body. If NAD+ drops, their energy supply drops too. Growth cycles slow down, hair loss can increase. Behind this is a clearly documented biological mechanism.
The skin is also affected. Collagen decreases by about 1% per year from our mid-20s. In the first five years after menopause, women lose up to 30% of their skin collagen. Both depend on the same DNA repair mechanisms, and those need NAD+ as an energy source.
These changes take the longest and are most noticeable once they are there. Women who notice a difference in their hair usually report it in the second to third month of consistent intake. The skin generally follows a bit later. These are individual experiences, and results vary.
A Simple Solution
NMN is not a quick fix, and it was never intended to be one. It is a daily restoration of something the body has been losing for years. The only variable is whether you stay consistent long enough to find out how the third month actually feels.
If you would like to dive deeper into the science behind everything covered here, we have compiled a free guide that covers the NAD+ decline, the research behind NMN, what you should look out for, and a full breakdown of what you can expect month by month. It is free and the most comprehensive resource we have on this topic.
Sources
1. Brincat, M. P., Baron, Y. M., & Galea, R. (2005). Effect of menopause on the skin. Climacteric, 8(Suppl 1), 11–23. https://doi.org/10.1080/13697130500161963
2. Cherradi, N., Defaye, G., & Chambaz, E. M. (2014). Mitochondrial 3β-hydroxysteroid dehydrogenase activity and NAD+ dependence. Journal of Biological Chemistry. https://doi.org/10.1074/jbc.M111.292490
3. 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
4. Hou, Y., Lautrup, S., Cordonnier, S., et al. (2018). NAD+ supplementation normalizes key Alzheimer's features and DNA damage responses. Proceedings of the National Academy of Sciences, 115(8), E1876–E1885. https://doi.org/10.1073/pnas.1718819115
5. Kim, M., Seol, J., Sato, T., Fukamizu, Y., Sakurai, T., & Okura, T. (2022). Effect of 12-week intake of nicotinamide mononucleotide on sleep quality, fatigue, and physical performance in older Japanese adults. Nutrients, 14(4), 755. https://doi.org/10.3390/nu14040755
6. Liao, B., Zhao, Y., Wang, D., Zhang, X., Hao, X., & Hu, M. (2021). Nicotinamide mononucleotide supplementation enhances aerobic capacity in amateur runners. Journal of the International Society of Sports Nutrition, 18(1), 54. https://doi.org/10.1186/s12970-021-00442-4
7. Massudi, H., Grant, R., Braidy, N., Guest, J., Farnsworth, B., & Guillemin, G. J. (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
8. Raichle, M. E., & Gusnard, D. A. (2002). Appraising the brain's energy budget. Proceedings of the National Academy of Sciences, 99(16), 10237–10239. https://doi.org/10.1073/pnas.172399499
9. Shuster, S., Black, M. M., & McVitie, E. (1975). The influence of age and sex on skin thickness, skin collagen and density. British Journal of Dermatology, 93(6), 639–643. https://doi.org/10.1111/j.1365-2133.1975.tb05100.x
10. Yaku, K., Okabe, K., & Nakagawa, T. (2018). NAD metabolism: Implications in aging and longevity. Ageing Research Reviews, 47, 1–17. https://doi.org/10.1016/j.arr.2018.05.006
11. 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