Infertility affects approximately 1 in 6 couples globally. Both male and female fertility are profoundly influenced by nutritional status. In women, key concerns include egg quality (oxidative stress in oocytes), ovulatory function, and uterine receptivity. In men, sperm count, motility, morphology, and DNA integrity are the primary parameters — all of which are influenced by oxidative stress and nutritional cofactors. Several supplements have RCT evidence for improving specific fertility parameters in both sexes.
Best Supplements for Fertility
We assessed each supplement for clinical evidence quality, mechanism of action, dosing transparency, and safety. Evidence grades: A = strong RCT evidence; B = good clinical evidence; C = preliminary or emerging evidence.
The most critical pre-conception supplement. 400–800 mcg/day of folate (ideally methylfolate/5-MTHF) before conception and through first trimester reduces neural tube defect risk by 50–70%. Also essential for DNA synthesis during rapid cell division. Women with MTHFR gene variants (40% of population) cannot efficiently convert folic acid to active methylfolate — use 5-MTHF directly.
Mitochondrial energy production is critical for both oocyte maturation (enormous energy demand) and sperm motility. CoQ10 declines with age — relevant to older women attempting conception. RCTs show CoQ10 improves egg quality markers and ovarian response in poor responders undergoing IVF. Meta-analysis shows CoQ10 significantly improves sperm motility (+74%) and concentration in infertile men.
Zinc is the most concentrated mineral in seminal plasma. Zinc deficiency directly causes oligospermia (low sperm count) and poor motility. RCTs show zinc supplementation improves sperm count, motility, and morphology in zinc-deficient men. Also essential for testosterone production and DHT metabolism in reproductive tissue.
Vitamin D receptors are expressed in ovarian follicles, the uterine endometrium, and testicular cells. Deficiency is associated with poor IVF outcomes, reduced sperm motility, and lower testosterone. Multiple studies show correction of vitamin D deficiency improves fertility outcomes in both sexes.
DHA is the dominant fatty acid in sperm head membranes — essential for the capacitation and acrosome reaction required for egg penetration. Studies show men with unexplained infertility have significantly lower sperm DHA. Omega-3 supplementation improves sperm morphology and motility in RCTs.
Beyond PCOS, myo-inositol improves oocyte quality, maturation rate, and embryo quality in IVF. Acts as an insulin sensitiser in the follicular microenvironment, improving ovarian response. Multiple RCTs in non-PCOS women show improved egg quality and fertilisation rates with 2,000–4,000 mg/day.
⚠ Safety & Medical Disclaimer
All pre-conception supplements should be disclosed to the fertility specialist or OB-GYN. Discontinue berberine, ashwagandha, and NAC when pregnancy is confirmed. High-dose vitamin A (>10,000 IU/day retinol) is teratogenic — avoid in pregnancy. Folate/folic acid is one of the few supplements universally recommended in pregnancy.
Frequently Asked Questions
Clinical References
All supplement recommendations are supported by peer-reviewed research. Key citations:
- Bentov Y et al. (2010). Mol Hum Reprod. The use of mitochondrial nutrients to improve the outcome of infertility treatment in older patients. → Source
- Lafuente R et al. (2013). J Assist Reprod Genet. Coenzyme Q10 and male infertility: a meta-analysis. → Source
- NIH Office of Dietary Supplements. Folate Fact Sheet. → Source