The most important thing to take for fertility is folic acid: 400 mcg daily for anyone trying to conceive. Beyond that foundation, the best supplements depend on whether the fertility challenge is on the female side, the male side, or both. A combination of targeted vitamins, antioxidants, and in some cases prescription medications can meaningfully improve your chances of getting pregnant.
Most fertility supplements need at least two to three months to make a difference, so starting early matters. Here’s what the clinical evidence supports.
Folic Acid: The Non-Negotiable Starting Point
The CDC recommends that all women capable of becoming pregnant get 400 mcg of folic acid every day. It’s the only form of folate proven to help prevent neural tube defects, which are serious birth defects of the brain and spine that develop in the earliest weeks of pregnancy, often before you know you’re pregnant. Start at least one month before trying to conceive.
If you’ve had a previous pregnancy affected by a neural tube defect, the recommendation jumps to 4,000 mcg daily, starting one month before conception and continuing through the first trimester. That’s a significant dose and worth discussing with your provider.
You’ll see supplements labeled as methylfolate (5-MTHF), which is a naturally occurring form of vitamin B9. Some people with certain gene variants absorb it more readily, but folic acid remains the form with the strongest evidence behind it for birth defect prevention.
Vitamin D and Pregnancy Rates
Vitamin D plays a larger role in conception than many people realize. In a study of women undergoing IVF, those with sufficient vitamin D levels at preconception were significantly more likely to become pregnant. The threshold that mattered was a blood level of at least 50 nmol/L (about 20 ng/mL). Women below that cutoff had roughly half the odds of a successful pregnancy.
Many adults are deficient without knowing it, especially those who live in northern climates or spend most of their time indoors. A simple blood test can check your level. Most prenatal vitamins contain some vitamin D, but if your levels are low, you may need a standalone supplement to reach the target range.
CoQ10 for Egg Quality
Coenzyme Q10 is an antioxidant your cells use to produce energy. Eggs are among the most energy-demanding cells in the body, and CoQ10 levels decline naturally with age. A meta-analysis of 20 clinical trials found that CoQ10 supplementation improved pregnancy rates in women with diminished ovarian reserve, particularly those under 35.
Interestingly, more isn’t necessarily better. The analysis found that a relatively low dose of 30 mg per day, taken for three months before an assisted reproduction cycle, was the optimal regimen for improving pregnancy rates. The key takeaway is consistency and timing: start well before you plan to conceive, since eggs take about three months to mature before ovulation.
Inositol for PCOS
If you have polycystic ovary syndrome, inositol is one of the most well-studied natural options for restoring regular ovulation. There are two forms that work together: myo-inositol and D-chiro-inositol. Research shows the most effective combination uses a 40:1 ratio of myo-inositol to D-chiro-inositol, which mirrors the natural ratio found in your blood.
This specific ratio has been shown in both animal and human studies to help reverse several hallmarks of PCOS, including irregular cycles and impaired insulin signaling, which directly affects ovulation. Most commercial inositol supplements designed for fertility already use this 40:1 ratio. The typical dose is 4,000 mg of myo-inositol combined with 100 mg of D-chiro-inositol daily.
What Men Should Take
Fertility supplements aren’t just for women. Sperm quality is a factor in roughly half of couples struggling to conceive, and several nutrients have strong evidence behind them.
Zinc increased total sperm motility by about 7% and boosted sperm concentration by approximately 1.5 million sperm per milliliter in a large meta-analysis of clinical trials. Carnitines (a compound your body uses to convert fat into energy) improved sperm motility by nearly 8% and progressive motility, meaning sperm that swim forward effectively, by about 7.5%. These are clinically meaningful differences that can shift borderline results into the normal range.
Timing matters for men too. Sperm take about 64 days to develop and mature, so any supplement needs at least two full months to influence the sperm being ejaculated. Starting three months before you plan to conceive gives supplements enough time to affect a complete cycle of sperm production.
Antioxidants That Support Both Partners
Oxidative stress damages both eggs and sperm. Several antioxidants show up repeatedly in fertility research.
- N-acetyl cysteine (NAC) has been studied as an add-on to fertility treatments. In one trial, women taking NAC alongside ovulation medication developed significantly more mature follicles than those on medication alone, with no increase in the risk of ovarian hyperstimulation.
- Vitamin C and vitamin E are commonly included in both male and female fertility protocols because they help protect cells from oxidative damage. They’re found in most quality prenatal vitamins.
- Selenium is a trace mineral involved in sperm formation and thyroid function, both of which affect fertility. Brazil nuts are one of the richest dietary sources.
A Note on Vitamin A Safety
Vitamin A is essential for reproductive health, but too much of the preformed type (retinol, found in liver and some supplements) can harm a developing baby. The European Food Safety Authority sets the upper limit at 3,000 mcg per day for women of childbearing age. UK experts recommend staying below 1,500 mcg daily because of potential bone effects. Most prenatal vitamins use beta-carotene instead, which your body converts to vitamin A only as needed, making toxicity far less likely. Check the label on any standalone vitamin A supplement you’re considering.
Prescription Medications for Ovulation
When supplements and lifestyle changes aren’t enough, prescription ovulation-inducing medications are typically the next step. The two most commonly prescribed options are clomiphene citrate (Clomid) and letrozole.
For women with PCOS, letrozole has emerged as the preferred choice. In a head-to-head comparison, letrozole produced a live birth rate of 27.5% compared to 19.1% with Clomid. Ovulation rates were also higher: 61.7% with letrozole versus 48.3% with Clomid. These medications require monitoring and are only available through a healthcare provider.
How Long Before Supplements Work
The biology dictates the timeline. Eggs go through their final maturation phase over roughly 90 days before ovulation, which is why most female fertility supplements are studied over a three-month window. For men, sperm development and maturation takes about 64 days from start to ejaculation.
This means the supplements you take today are improving the eggs and sperm that will be available two to three months from now. If you’re planning to conceive, starting a fertility-focused regimen at least three months in advance gives your body the best chance to respond. Prenatal vitamins with folic acid should ideally start even earlier, since neural tube closure happens within the first few weeks after conception.