NMN and Fertility: Does It Improve Egg Quality and Sperm Health?
The short answer: NMN supports fertility indirectly by restoring NAD+, the molecule that powers egg maturation, sperm motility, and reproductive DNA repair — all of which decline with age. No large-scale human fertility trial has concluded yet, but the preclinical evidence is among the strongest in all of NMN research, and a small 2025 retrospective study in women with diminished ovarian reserve reported doubled fertilisation rates in NMN users versus controls.
Fertility is fundamentally a cellular energy problem. People rarely frame it that way, but that's what the biology says.
For conception to succeed, eggs must divide with extraordinary precision, sperm must sustain propulsive motility across enormous distances relative to their size, and embryos must generate enough energy to develop through the critical early stages. All of this demands a molecule called NAD+ — and NAD+ falls by an estimated 40–50% between the ages of 40 and 70.
NMN (nicotinamide mononucleotide) is the most direct precursor to NAD+ in the body. As interest in NMN has expanded beyond general longevity into more specific health questions, fertility has come up as one of the most scientifically substantive areas of enquiry, particularly for women in their 30s and 40s navigating age-related declines in egg quality, and for men dealing with oxidative stress-driven sperm damage.
Here's what the evidence actually shows.
What Is NMN and Why Does It Matter for Reproduction?
NMN (nicotinamide mononucleotide) is a naturally occurring molecule that the body converts directly into NAD+, a coenzyme essential for cellular energy production, DNA repair, mitochondrial function, and sirtuin activation. NAD+ levels decline significantly with age, and reproductive cells — particularly oocytes — are among the most vulnerable.
If you're new to NMN, our guide on how NMN works in the body explains the core mechanism. In the context of fertility, the relevant biology is this: eggs and sperm are not passive bystanders to ageing. They are energy-intensive, rapidly dividing cells whose quality is directly regulated by the cellular machinery that NAD+ powers.
The Fertility–NAD+ Connection at a Glance
| Process | Why It Matters for Fertility | Impact of NAD+ Decline |
|---|---|---|
| Mitochondrial energy production | Powers egg maturation, sperm motility, embryo development | Reduced oocyte quality, sluggish sperm |
| Meiotic spindle assembly | Ensures correct chromosome segregation in dividing eggs | Chromosomal errors (aneuploidy), miscarriage risk |
| DNA repair (PARP enzymes) | Protects genetic integrity of gametes | DNA fragmentation in sperm; egg genomic instability |
| SIRT2 activation | Regulates oocyte chromosome alignment and cell cycle | Disorganised meiosis, reduced fertility |
| Oxidative stress defence | Protects eggs and sperm from free radical damage | Lipid peroxidation, cell death, sperm morphology defects |
| Hormonal regulation (AMPK-SIRT1 axis) | Supports insulin sensitivity and ovarian function | Disrupted ovulation, PCOS-related fertility impairment |
NMN and Female Fertility: What the Research Shows
Egg Quality Is the Rate-Limiting Factor — and NAD+ Is Central to It
Women are born with their lifetime supply of eggs. Unlike most cells, oocytes cannot be replaced. As women age, the NAD+ content within individual oocytes falls — a finding confirmed using hyperspectral microscopy imaging in a landmark Cell Reports study (Bertoldo et al., 2020). Crucially, this decline occurs within the oocytes themselves, while surrounding ovarian tissue maintains relatively higher NAD+ levels, making the egg uniquely vulnerable.
That same study demonstrated that NMN treatment in aged mice restored NAD+ levels within oocytes and rescued spindle assembly — the process that ensures chromosomes divide correctly during fertilisation. Aged mice treated with NMN achieved live birth rates comparable to young mice.
A 2024 study published in MedComm (open access, Wiley) went further, examining NMN's effect on the whole ovarian environment. Ovarian NAD+ levels declined by 50–70% in ageing mice. NMN administration reversed ovarian atrophy, restored hormone secretion, reduced pro-inflammatory cytokines, and increased both the quantity and quality of ovulated oocytes. The researchers used transcriptomic analysis to confirm the mechanism: NMN improved mitochondrial function and reduced ovarian inflammation via identifiable molecular pathways.
Most recently, a 2025 systematic review published in the Journal of Assisted Reproduction and Genetics synthesised seven high-quality preclinical studies and integrated single-oocyte RNA sequencing across 46 human oocytes. The review confirmed that NAD+-related gene expression is active and relevant across all key stages of human oocyte maturation — providing the first direct molecular evidence that NMN's preclinical findings are likely applicable to human reproductive biology.
The 2025 Human Data: Cautiously Promising
A retrospective analysis presented in Human Reproduction (Sharma et al., 2025) examined women with diminished ovarian reserve (DOR). Those who had taken NMN showed a fertilisation rate of 48% versus 24% in those who had not — and better follicle growth. This was not a randomised controlled trial, and the evidence is preliminary. But it is the first human reproductive outcome data to emerge, and the effect size is large enough to warrant the ongoing RCTs (NCT06629636 in Japan; NCT06426355 in China) that are currently testing 600–900 mg/day NMN in IVF populations.
The fertility research is the area where I personally find NMN's biology most striking. The idea that eggs are depleted in the very molecule that powers their division — and that you can replenish it — is one of the most mechanistically coherent findings in the longevity supplement space. It's also one of the reasons I think NMN deserves more attention from women thinking proactively about reproductive health, not just those actively in IVF cycles. — Mat Stuckey, Longevity Formulas
NMN and IVF: Clinics Are Already Using It
One angle missing from most online coverage: fertility clinics aren't waiting for the RCTs. North Cyprus IVF Centre has incorporated NMN supplementation as a standard component of IVF protocols for older women with diminished ovarian activity, prescribing it for 8 weeks prior to egg retrieval. A 2025 paper in the American Journal of Obstetrics and Gynecology (Ramírez-Martín et al.) studied NMN supplementation in both mouse models of chemotherapy-induced ovarian damage and directly in human oocytes from women aged over 38 — finding that NMN improved mitochondrial redistribution, recovered NAD+ levels (p = 0.006), and restored fertilisation rates (p = 0.003).
PCOS: An Overlooked Angle
A 2024 review in Biochemistry and Biophysics Reports highlighted NMN's potential relevance for women with PCOS (polycystic ovary syndrome) — a leading cause of female infertility. The AMPK-SIRT1 pathway, activated by higher NAD+ levels, helps regulate insulin sensitivity and reduces chronic inflammation, both of which are central mechanisms in PCOS-related ovarian dysfunction. This is a relatively underexplored application with significant potential.
NMN and Male Fertility: A More Complicated Picture
The Core Case: Sperm Are Energy-Dependent Cells
Sperm are among the most mitochondria-dependent cells in the human body — their entire propulsive function is powered by ATP generated through the electron transport chain. Mitochondrial efficiency in sperm declines with age and metabolic stress, reducing motility and increasing DNA fragmentation.
Multiple animal studies support NMN's role in sperm quality:
- A 2022 study found NMN reversed diabetes-induced male infertility in mice by restoring testicular structure, increasing sperm count, and rescuing glycolytic enzyme activity in the testes.
- Research on boar sperm (physiologically close to human sperm) found that NMN at 20 µM significantly improved sperm motility, acrosome integrity, and mitochondrial activity — with elevated intracellular NAD+ and ATP levels confirmed (p < 0.05). The mechanism was identified as SIRT3 activation via the SIRT3-SOD2/ROS pathway.
- NMN improved sperm quality in obese mice by reducing oxidative stress and mitochondrial dysfunction linked to high-fat diet exposure.
The Nuance: High NAD+ in Sperm Isn't Always Better
Contrary to popular assumption, the relationship between NAD+ and male fertility is not simply "more is better." A 2022 cohort study in BMC Urology examined 51 men across three age groups and found a negative correlation between intracellular sperm NAD+ levels and sperm quality parameters — specifically concentration, motility, and DNA fragmentation index. The proposed mechanism: excessively elevated NAD+ can overstimulate mitochondrial activity in sperm, generating reactive oxygen species (ROS) that cause oxidative damage rather than prevent it.
This finding does not undermine NMN's relevance for male fertility — it contextualises it. For ageing men where NAD+ has fallen well below optimal, NMN supplementation that restores depleted levels is a different proposition to artificially elevating already-adequate NAD+ above physiological norms. As with most interventions in longevity biology, the goal is restoration rather than supraphysiological enhancement.
The 3-Month Timing Window: Why It Matters
One of the most practically important pieces of information for anyone using NMN as part of a fertility strategy: oocytes take approximately 90 days to mature from the primordial follicle stage through to ovulation. This means the supplementation window that matters is the 8–12 weeks before egg retrieval or natural conception — not the week before.
This is why:
- The NMN fertility trials testing 600–900 mg/day use multi-month protocols
- North Cyprus IVF prescribes NMN 8 weeks before retrieval
- Short-term supplementation of a few days is unlikely to be meaningful for egg quality
The same logic applies loosely to sperm, which undergo a complete maturation cycle (spermatogenesis) over approximately 72–74 days. Any quality-influencing intervention needs to be sustained for at least this duration to affect the sperm that will actually be used for fertilisation.
Safety Considerations Around NMN and Fertility
NMN is well-tolerated in human trials up to 900 mg/day with no significant adverse effects reported. However, there are important caveats specific to the fertility context:
- Safety during pregnancy: There is currently no human safety data on NMN during pregnancy. Animal studies have not shown teratogenicity, but out of caution, supplementation should be discontinued immediately upon a positive pregnancy test or embryo transfer.
- IVF patients: Anyone undergoing fertility treatment should discuss NMN with their reproductive endocrinologist before supplementing. Some clinics are integrating it; others are not yet familiar with the research.
- NMN and oestrogen: A common question is whether NMN affects oestrogen levels. Our article on does NMN raise oestrogen covers this directly.
I think the honest conversation around NMN and fertility — one that most supplement brands avoid — is acknowledging that the human trial data is still early. The preclinical evidence is of course, compelling, and the IVF clinic adoption is a meaningful signal. But anyone making significant fertility decisions should be working with their doctor, not relying on a supplement alone. NMN may well become a standard part of reproductive medicine as the trials report. Right now, it's a very well-supported adjunct, not a treatment. — Mat Stuckey, Longevity Formulas
How to Use NMN for Fertility Support: Practical Guidance
| Parameter | Current Guidance |
|---|---|
| Dose | 250–500 mg/day (general use); 600–900 mg/day being tested in IVF trials |
| Timing | Morning, with or without food |
| Duration before conception/retrieval | Minimum 8 weeks; 12 weeks preferable to cover full oocyte/sperm cycle |
| When to stop | Upon confirmed pregnancy or embryo transfer |
| Professional consultation | Essential if actively undergoing fertility treatment |
For dosage guidance more broadly, see our complete NMN dosage guide.
Frequently Asked Questions
Does NMN improve egg quality?
Preclinical evidence strongly suggests NMN can restore NAD+ levels in aged oocytes, improve meiotic spindle assembly, and increase both egg quantity and quality in animal models. A 2025 systematic review confirmed NAD+-related gene activity in human oocytes at all maturation stages. Human trial data is preliminary but directionally positive.
Can NMN help with IVF outcomes?
A 2025 retrospective study showed a fertilisation rate of 48% in women with diminished ovarian reserve who took NMN, versus 24% in those who did not. Randomised trials are ongoing. Some fertility clinics are already incorporating NMN into IVF protocols for older patients.
Does NMN help male fertility?
Animal studies show NMN can improve sperm motility, acrosome integrity, and mitochondrial function — particularly in metabolically compromised contexts (obesity, diabetes). For healthy men, the picture is more nuanced: NMN appears most beneficial where NAD+ has already been depleted, rather than as a universal sperm enhancer.
Is NMN safe to take when trying to conceive?
NMN is well tolerated in healthy adults at doses up to 900 mg/day. It should be stopped at the point of confirmed pregnancy pending safety data. Anyone undergoing IVF or fertility treatment should discuss it with their clinician.
Does NMN affect hormones?
NMN may support hormonal regulation indirectly through the AMPK-SIRT1 pathway. For more detail on NMN's relationship with oestrogen specifically, see our dedicated article on does NMN raise oestrogen.
How long does NMN take to work for fertility?
Given the 90-day oocyte maturation window and ~74-day sperm cycle, meaningful effects on gamete quality would require a minimum of 8–12 weeks of consistent supplementation. Shorter periods are unlikely to influence the cells involved in conception.
What else supports fertility alongside NMN?
Resveratrol activates SIRT1 complementarily to NMN's NAD+ restoration — see our piece on NMN and resveratrol. CoQ10 is also widely used in reproductive medicine for mitochondrial support. Diet, sleep quality, and oxidative stress management remain the highest-leverage lifestyle factors.
The Bottom Line
The science connecting NMN to fertility is among the most mechanistically coherent in the entire longevity supplement landscape. The oocyte is the single most NAD+-dependent cell with respect to quality outcomes; NAD+ declines in eggs with age; NMN restores it. That logical chain is supported by multiple independent preclinical studies, beginning-of-human data, and real-world clinical adoption.
What it is not — yet — is proven by a large randomised controlled trial in humans. Anyone navigating a fertility journey deserves that honesty alongside the genuine optimism the research justifies.
For those looking to understand NMN more broadly before making decisions, our articles on what is NMN and NMN before and after results should offer you some useful context, alongside our pure, tested NMN supplement for those ready to supplement.
References - https://pubmed.ncbi.nlm.nih.gov/41160202/
This article is for educational purposes only and does not constitute medical advice. NMN supplements are not a fertility treatment and should not replace specialist fertility care. Always consult a qualified healthcare professional before supplementing, particularly if pregnant, breastfeeding, or undergoing fertility treatment.
