Several vitamins and supplements have solid evidence behind them for improving fertility in both women and men. Folic acid, vitamin D, CoQ10, omega-3 fatty acids, and a handful of minerals can each target a different piece of the fertility puzzle, from egg quality to sperm health to the thickness of your uterine lining. Starting a prenatal vitamin at least three months before you try to conceive gives these nutrients time to make a measurable difference.
Folic Acid: The Non-Negotiable Starting Point
The CDC recommends that all women capable of becoming pregnant get 400 micrograms of folic acid every day. This is primarily to prevent neural tube defects, which develop in the earliest weeks of pregnancy, often before you even know you’re pregnant. Folic acid is the only form of folate shown to prevent these birth defects, so food sources of natural folate alone aren’t a reliable substitute. Most prenatal vitamins contain at least 400 mcg, and some provide 600 to 800 mcg for women at higher risk.
Vitamin D and Pregnancy Rates
Vitamin D plays a direct role in reproductive hormone regulation, and your blood levels appear to influence your chances of conceiving. A retrospective study of women undergoing IVF found that those with sufficient vitamin D levels (above 75 nmol/L, or roughly 30 ng/mL) had a cumulative live birth rate of about 52%, compared to 44% in women who were deficient. That’s a meaningful gap.
Many people are unknowingly low in vitamin D, especially those who live in northern climates, have darker skin, or spend most of their time indoors. A simple blood test can check your levels. If you’re below the sufficient range, supplementation with vitamin D3 can help bring you into the target zone over several weeks.
CoQ10 for Egg Quality
CoQ10 is an antioxidant your cells use to produce energy. It’s concentrated in the mitochondria, the tiny power plants inside every cell, including your eggs. As you age, mitochondrial function in eggs declines, which is one reason fertility drops after 35. CoQ10 supplementation aims to support that energy production and reduce chromosomal errors during egg maturation.
Research published in Fertility and Sterility tested CoQ10 on immature eggs from women aged 38 and older and found it reduced certain types of chromosomal abnormalities that occur during the final stages of egg development. Fertility clinics commonly recommend CoQ10 (often in the more absorbable ubiquinol form) for women over 35 who are trying to conceive, with typical daily doses ranging from 200 to 600 mg. It takes about two to three months of supplementation to influence egg quality, since eggs go through their final maturation cycle over roughly 90 days.
Vitamin E and Uterine Lining
Even a healthy embryo needs a receptive uterine lining to implant successfully. A thin endometrium is a common barrier to pregnancy, particularly for women undergoing fertility treatments. A systematic review and meta-analysis found that women who took oral vitamin E had significantly thicker endometrial linings than those who didn’t supplement.
The mechanism is straightforward: vitamin E increases capillary blood flow to the uterus, which delivers more oxygen and nutrients to the endometrial tissue. It also promotes the growth of endometrial glands and blood vessels. This makes it particularly relevant for women whose doctors have flagged a thin lining as a potential issue.
Omega-3 Fatty Acids
Omega-3s, specifically EPA and DHA found in fish oil, support fertility through several pathways. They help regulate the hormonal signaling needed for ovulation, increase blood flow to the uterus, reduce chronic inflammation that can interfere with implantation, and may improve an embryo’s ability to attach to the uterine wall. A common recommendation for couples trying to conceive is 1,000 mg of combined omega-3 fatty acids daily. Both partners benefit, since omega-3s also support sperm membrane integrity.
Iron: A Targeted Benefit
Iron’s effect on fertility is more nuanced than most supplement lists suggest. A large study tracking nearly 4,700 women trying to conceive found that heme iron (from meat) had no effect on time to pregnancy. Non-heme iron, the type found in vegetables and supplements, did slightly improve conception rates, but only in specific groups: women who had previously given birth and women with heavy periods or short menstrual cycles. These are the women most likely to have depleted iron stores.
If your periods are light and your iron levels are normal, extra iron supplementation probably won’t speed things up. But if you experience heavy bleeding each month, checking your ferritin levels and supplementing if they’re low is a reasonable step.
Inositol for PCOS-Related Infertility
Polycystic ovary syndrome is one of the most common causes of irregular ovulation, and inositol has become a go-to supplement for women with PCOS who are trying to conceive. Myo-inositol acts as a signaling molecule that helps your cells respond to insulin more effectively. Since insulin resistance drives many PCOS symptoms, including irregular cycles and excess androgens, improving insulin sensitivity can restore regular ovulation.
The most effective formulation appears to be a combination of myo-inositol and D-chiro-inositol in a 40:1 ratio. This mirrors the natural ratio found in your body. Women with PCOS who take this combination often see improvements in cycle regularity within two to three months. If you don’t have PCOS, inositol is unlikely to offer the same benefit.
Supplements That Support Male Fertility
Nearly half of all fertility challenges involve a male factor, so it’s worth looking at what helps sperm quality too. Zinc and selenium are the two most studied minerals for male reproductive health.
Zinc concentration in seminal fluid correlates with sperm count, motility, and viability. It also helps reduce oxidative stress that can damage sperm DNA. Most men get adequate zinc from a balanced diet, but those with low intake or absorption issues may benefit from supplementation.
Selenium has shown mixed results. One well-designed trial found that 200 mcg per day for 26 weeks improved total sperm count, normal morphology, and motility in subfertile men. But a higher dose of 300 mcg per day showed no benefit, and intakes above 400 mcg per day actually reduced sperm motility in fertile men. This is a case where more is clearly not better.
CoQ10 and omega-3s also benefit sperm quality, making them useful supplements for both partners to take during the preconception period.
Vitamin A: Important but Easy to Overdo
Vitamin A is essential for cell development and reproduction, but the preformed version (retinol, found in liver and some supplements) carries real risk during early pregnancy. The European Food Safety Authority set the tolerable upper intake at 3,000 mcg per day for women of childbearing age, based on the risk of birth defects and liver damage. The UK’s Expert Committee on Vitamins and Minerals considers anything above 1,500 mcg per day inappropriate due to potential bone effects.
Most prenatal vitamins use beta-carotene instead of retinol, which your body converts to vitamin A only as needed. This eliminates the toxicity risk. If you’re taking a standalone vitamin A supplement or eating liver regularly, check the form and amount before trying to conceive.
When to Start and What to Expect
The Mayo Clinic recommends starting prenatal vitamins before conception, with folic acid ideally begun at least three months ahead. This three-month window matters for several reasons. Folic acid needs time to build up in your tissues. Egg maturation takes about 90 days, so supplements like CoQ10 that target egg quality need that full cycle to take effect. Sperm production also operates on a roughly three-month timeline, so male partners benefit from the same head start.
A quality prenatal vitamin covers your baseline needs for folic acid, vitamin D, and iron. Supplements like CoQ10, omega-3s, and inositol are typically taken separately. If you’re unsure about your vitamin D or iron levels, a blood test before you start trying gives you a clear picture of where you stand and what’s worth adding to your routine.