NMN restores follicles (mice)

Ovarian follicles are the tiny sacs that hold immature eggs, and a new mouse study reported that nicotinamide mononucleotide raised their numbers in older animals after 10 days. (link.springer.com) The paper, published April 8 in *Reproductive Sciences*, gave aged female mice 200, 500, or 1,000 milligrams per kilogram per day of nicotinamide mononucleotide and compared them with aged and young controls. The authors said 500 milligrams per kilogram per day was the best dose for restoring ovarian follicle reserve. (link.springer.com) Nicotinamide mononucleotide is a precursor to nicotinamide adenine dinucleotide, or NAD, a molecule cells use in energy production. The study said treated mice had higher ovarian NAD and adenosine triphosphate, lower oxidative stress and cell death in oocytes, and better mitochondrial function. (link.springer.com) The same paper reported a second result outside the animals: adding 1 micromolar nicotinamide mononucleotide to culture media improved the developmental potential of aged oocytes in vitro. The authors linked those changes to the NAD, sirtuin 1, proliferator-activated receptor gamma coactivator 1-alpha pathway and to higher TOMM20 expression, all markers tied to mitochondrial maintenance. (link.springer.com) This result lands in a field that has been trying to explain why fertility drops with age even before menopause. A 2020 *Cell Reports* study found that replenishing NAD in mice improved ovulation, oocyte quality, embryo development, and live births during reproductive aging. (cell.com) Another mouse study, published in 2022 in *The Journal of Nutritional Biochemistry*, used a much longer 20-week treatment in 40-week-old mice and reported increases in primordial, primary, secondary, and antral follicles, along with improved estrous cycles and endocrine function. That work pointed to improved mitochondrial recycling in granulosa cells, the support cells that help eggs mature. (pubmed.ncbi.nlm.nih.gov) Human evidence is thinner and asks different questions. A 2023 randomized, placebo-controlled trial in 80 healthy middle-aged adults tested 300, 600, and 900 milligrams a day for 60 days and found dose-dependent increases in blood NAD, but it was not a fertility trial. (pmc.ncbi.nlm.nih.gov) That gap is the key limit on the mouse result. Changes in follicle counts, hormone levels, or mitochondrial markers in mice do not show that nicotinamide mononucleotide restores ovarian reserve or improves pregnancy rates in women, and the new paper did not report human data. (link.springer.com) The supplement has also drawn regulatory attention in the United States. The National Institutes of Health Dietary Supplement Label Database lists nicotinamide mononucleotide products, and the Natural Products Association said on December 10, 2025, that the Food and Drug Administration had confirmed it can be marketed as a dietary supplement after reversing its 2022 position. (dsld.od.nih.gov) (npanational.org) For now, the clearest claim is the narrow one the mouse data support: in aged female mice, short-course nicotinamide mononucleotide changed ovarian markers that track with egg reserve. Whether that can be repeated safely in women will depend on clinical trials that have not yet answered the fertility question. (link.springer.com)