Several supplements have credible evidence behind them for supporting fertility, though the strength of that evidence varies. The most studied options target egg quality, sperm health, ovulation regularity, and the nutritional foundation needed for a healthy pregnancy. Here’s what the research actually shows for each one.
Folic Acid: The Non-Negotiable Starting Point
Folic acid isn’t just a pregnancy supplement. The CDC recommends that all women capable of becoming pregnant take 400 micrograms (mcg) daily, ideally before conception. Its primary role is preventing neural tube defects, serious birth defects of the brain and spine that develop in the earliest weeks of pregnancy, often before you even know you’re pregnant. This is one of the few supplements with universal, institutional backing, and it belongs in any fertility plan from day one.
CoQ10 for Egg Quality
Coenzyme Q10 is a naturally occurring antioxidant that helps your cells produce energy. Every cell relies on it, but eggs are especially energy-hungry. As you age, your cells’ energy-producing structures become less efficient, and CoQ10 levels decline. Supplementing may help compensate for that decline by reducing oxidative stress and supporting the cellular energy production that eggs need to mature properly.
Most studies use doses between 200 and 600 mg per day, typically split into two or three doses. For women over 35, many reproductive endocrinologists recommend 300 to 600 mg daily, started at least 8 to 12 weeks before trying to conceive or beginning IVF. That lead time matters because eggs take roughly three months to mature, so you want CoQ10 on board during that entire window.
Inositol for PCOS-Related Ovulation Problems
If you have polycystic ovary syndrome (PCOS), inositol is one of the most relevant supplements to know about. There are two forms that matter: myo-inositol and D-chiro-inositol. Both play roles in how your body responds to insulin, which is central to the hormonal imbalance driving PCOS symptoms like irregular or absent ovulation.
Research published in Frontiers in Endocrinology found that combining the two forms in a specific 40:1 ratio (myo-inositol to D-chiro-inositol) produced the best results, closely matching the ratio naturally found in human blood. Animal studies showed near-full recovery from PCOS signs at this ratio, and clinical studies in women with PCOS have confirmed those findings. Many supplements marketed for PCOS fertility now use this 40:1 formulation. If you’re shopping for one, check the label for the ratio, not just the presence of both forms.
Vitamin D and Conception Rates
Vitamin D’s role in fertility is real but more nuanced than supplement marketing suggests. A cohort study tracking couples trying to conceive found that when the male partner had sufficient vitamin D levels (30 ng/mL or above), the couple was nearly four times more likely to conceive within six months compared to couples where the man was deficient. Time to pregnancy was also shorter.
Interestingly, the same study found no significant link between the woman’s preconception vitamin D levels and conception rates. However, sufficient vitamin D during the third trimester was associated with reduced odds of anemia, longer gestational age, and healthier newborn weight. So while vitamin D may not directly boost a woman’s chances of getting pregnant, it supports a healthier pregnancy once conception occurs. For men, getting levels above 30 ng/mL appears genuinely meaningful. A simple blood test can tell you where you stand.
Zinc and Selenium for Sperm Health
Zinc is one of the most studied minerals for male fertility. It plays a documented role in sperm production, and supplementation has been linked to improvements in sperm count, motility (how well sperm swim), and morphology (the percentage of normally shaped sperm). The exact biological mechanism isn’t fully understood, but the positive effects on sperm parameters show up consistently across studies.
Selenium has a thinner evidence base. One randomized, placebo-controlled trial gave subfertile men 200 mcg of selenium daily for 26 weeks. Even though none of the men were deficient at the start, their total sperm count, concentration, normal morphology, and motility all improved relative to the placebo group. The challenge is that most research on these minerals tests them alongside other nutrients, making it hard to isolate exactly how much each one contributes on its own. Still, both are reasonable additions to a male fertility supplement regimen, especially if dietary intake is low.
L-Carnitine for Sperm DNA and Motility
L-carnitine is an amino acid derivative that helps cells convert fat into energy. In the context of male fertility, it has shown effects across multiple dimensions of sperm health. Studies on infertile men have found that supplementation improved sperm motility, the percentage of normally shaped sperm, and, perhaps most importantly, reduced DNA fragmentation. DNA fragmentation is a measure of genetic damage within sperm cells, and high levels are associated with failed fertilization, poor embryo development, and miscarriage.
A 2019 study on 80 infertile men with elevated sperm DNA fragmentation found that L-carnitine supplementation decreased both DNA damage and free oxygen radicals while improving motility and morphology. A larger study of 175 men with low sperm count and poor motility showed similar reductions in DNA fragmentation along with improved movement. Results for sperm concentration are less consistent: some studies report increases, while others find no significant change in density. The most reliable benefit appears to be in motility and DNA integrity.
What the Medical Establishment Says
It’s worth knowing that major fertility organizations remain cautious. The American Society for Reproductive Medicine issued a strong recommendation in its 2024 guidelines stating that there is insufficient evidence to support the use of nutrient supplements and herbal medicines for conditions like premature ovarian insufficiency. That doesn’t mean supplements are useless. It means the gold-standard clinical trials needed for a formal medical endorsement largely haven’t been done yet, particularly for female fertility supplements beyond folic acid.
The evidence is generally stronger on the male side, where measurable sperm parameters give researchers concrete outcomes to track. For women, egg quality and ovarian function are harder to measure directly, so studies tend to be smaller and less definitive. This gap between promising early research and definitive proof is where most fertility supplements currently sit.
Choosing a Quality Supplement
Supplements aren’t regulated the way prescription drugs are, which means what’s on the label doesn’t always match what’s in the bottle. Look for products verified by a recognized third-party certification program. The most well-vetted seals to look for are USP Verified, NSF Certified Sport, BSCG Certified Drug Free, and Informed Sport. These programs test for label accuracy, contaminant screening, and the absence of banned substances.
Timing also matters more than most people realize. Eggs take about three months to mature, and the full cycle of sperm production runs roughly 72 days. Starting supplements at least two to three months before you plan to actively try gives the relevant cells time to benefit. Beginning a week before isn’t going to move the needle.