Fertility Supplements: An Evidence-Based Review

The fertility supplement market is huge — and most of it is marketing. Here's what actually has evidence behind it, graded by the strength of that evidence.

How We Graded the Evidence

We use a simplified evidence grading system:

Level 1 (Strong): Multiple randomized controlled trials or meta-analyses. Level 2 (Moderate): One or more good RCTs with consistent results. Level 3 (Limited): Observational studies, small trials, or inconsistent results. Level 4 (Insufficient): Anecdotal, animal studies, or no meaningful clinical data.

Supplements With Meaningful Evidence

Folate / Folic Acid — Level 1

The most well-established fertility supplement. 400–800mcg daily is recommended for all women of reproductive age, starting at least 1–3 months before conception. Prevents neural tube defects and may support egg quality. Methylfolate (5-MTHF) is the active form and bypasses MTHFR conversion, though folic acid works for most women.

Coenzyme Q10 (CoQ10) — Level 2

CoQ10 is a mitochondrial antioxidant that supports cellular energy production in eggs. As eggs age, mitochondrial function declines — CoQ10 may help compensate. Dosage: 400–600mg daily. Multiple studies show improved egg quality and IVF outcomes, particularly in women over 35. Ubiquinol (reduced form) may be better absorbed than ubiquinone.

DHEA — Level 2 (Specific Indication)

DHEA (dehydroepiandrosterone, 25mg three times daily) has moderate evidence for improving ovarian response in women with diminished ovarian reserve specifically. It should be used under physician supervision — DHEA can affect androgen levels and isn't appropriate for everyone. Typically taken for 2–3 months before an IVF cycle.

Vitamin D — Level 2

Vitamin D deficiency is common (40–50% of US adults) and correlates with lower IVF success rates. Optimal levels for fertility: 40–60 ng/mL. Most people need 2,000–4,000 IU daily to reach optimal levels. Get tested and supplement accordingly.

Inositol — Level 2 (for PCOS)

Myo-inositol (2–4g daily) has strong evidence for improving ovulation and metabolic markers in women with PCOS. It improves insulin sensitivity, reduces androgens, and can restore regular ovulation. The combination of myo-inositol + D-chiro-inositol in a 40:1 ratio is the most studied formulation. Less evidence for women without PCOS.

Omega-3 Fatty Acids (DHA/EPA) — Level 2–3

Omega-3s support hormone production, reduce inflammation, and may improve egg quality. 250–500mg DHA daily is also critical during pregnancy for fetal brain development. Look for third-party tested fish oil or algae-based options.

Supplements With Limited Evidence

Vitamin E — Level 3

Antioxidant properties may benefit both egg and sperm quality. Some evidence for improving endometrial thickness. Dosage: 200–400 IU daily.

Selenium — Level 3

Important for thyroid function and antioxidant defense. May support sperm motility and reduce miscarriage risk in selenium-deficient populations. 55–100mcg daily.

NAC (N-Acetyl Cysteine) — Level 3

Antioxidant and mucolytic. Some evidence for improving ovulation in PCOS (often studied alongside clomiphene). May support endometrial thickness. 600–1,800mg daily.

Supplements That Are Overhyped

Royal Jelly — Level 4

Popular in wellness circles, but clinical evidence is essentially absent. Animal studies exist; human trials are lacking. Unlikely to cause harm, but don't rely on it.

Maca Root — Level 4

Traditional use for fertility and libido. Very limited human fertility data. Some studies show hormonal effects, but nothing that translates to clinical pregnancy rates.

Proprietary Fertility Blends — Variable

Products like FertilAid, Conception, and Pink Stork often combine ingredients with evidence (folate, CoQ10) and ingredients without it (herbs, proprietary extracts) at undisclosed doses. You're usually better off buying individual supplements at clinically studied doses.