The most important supplement when trying to conceive is folic acid, taken at 400 micrograms daily, ideally starting at least one month before conception. Beyond that baseline, a handful of other nutrients have solid evidence behind them for both egg and sperm quality. Here’s what’s worth taking, what to watch out for, and what your partner should consider too.
Folic Acid: The Non-Negotiable
Folic acid prevents neural tube defects, which are serious birth defects of the brain and spine that develop in the first few weeks of pregnancy, often before you know you’re pregnant. The standard recommendation from the American College of Obstetricians and Gynecologists is 400 micrograms per day for all women of reproductive age. If you’ve had a previous pregnancy affected by a neural tube defect or you take seizure medications, the recommended dose jumps to 4 milligrams daily.
Most prenatal vitamins contain 400 to 800 micrograms, so if you’re already taking one, you’re likely covered. You may have seen advice online suggesting that people with MTHFR gene variants should skip folic acid in favor of methylfolate. The CDC has addressed this directly: people with common MTHFR variants can process folic acid just fine, and 400 micrograms daily raises blood folate levels regardless of MTHFR genotype. Folic acid remains the only form of folate proven to prevent neural tube defects.
Vitamin D and Fertility Outcomes
Vitamin D plays a role in reproductive hormone regulation, and low levels are common. A retrospective study of women undergoing IVF found that those with sufficient vitamin D levels had a cumulative live birth rate of about 52%, compared to roughly 44% in women who were deficient. That’s a meaningful gap, and the pattern held across the full range of vitamin D status: higher levels corresponded to better outcomes.
The tricky part is that most women in the study were deficient or insufficient, which reflects the general population. If you haven’t had your vitamin D checked recently, it’s worth asking for a blood test. Many prenatal vitamins include some vitamin D, but not always enough to correct a deficiency. Typical supplemental doses range from 1,000 to 2,000 IU daily, though your doctor may recommend more based on your bloodwork.
CoQ10 for Egg Quality
Coenzyme Q10 supports the energy-producing structures inside cells, and eggs are among the most energy-demanding cells in the body. As you age, the mitochondria in your eggs become less efficient, which is one reason fertility declines with time. CoQ10 supplementation aims to support that cellular energy production.
Dosages used in fertility research for women range from 200 to 600 milligrams per day. CoQ10 is fat-soluble, so it absorbs better when taken with a meal that contains some fat. It’s generally well tolerated, though it can interact with blood thinners. This supplement is most commonly recommended for women over 35 who are concerned about age-related changes in egg quality.
Omega-3 Fatty Acids
Omega-3s, particularly EPA and DHA found in fish oil, support hormone regulation and increase blood flow to the uterus, both of which matter for ovulation and implantation. A commonly cited target is 1,000 milligrams of combined omega-3s per day, and this is one supplement that benefits both partners.
If you eat fatty fish like salmon or sardines two to three times a week, you may already be getting enough. For everyone else, a fish oil or algae-based supplement fills the gap. Look for one that lists the EPA and DHA content separately on the label rather than just “fish oil,” since total fish oil and actual omega-3 content are different numbers.
Supplements for Your Partner
Fertility is a two-person effort, and sperm quality is directly influenced by nutrition. Oxidative stress is estimated to play a role in 30% to 80% of cases of reduced sperm quality. It damages sperm DNA, reduces motility, and impairs the sperm’s ability to fuse with an egg. Antioxidants help counteract this, but balance matters. Too many antioxidants can actually interfere with normal sperm function, since sperm need a small amount of reactive oxygen species to mature and function properly.
A Cleveland Clinic review of 90 ingredients found in male fertility supplements determined that only about 17% had evidence of a positive effect on sperm parameters. The ingredients with the strongest support were:
- L-carnitine: supports sperm energy metabolism and motility
- Vitamin E: protects sperm cell membranes from oxidative damage
- Vitamin C: works alongside vitamin E as an antioxidant in seminal fluid
- CoQ10: supports mitochondrial function in sperm, similar to its role in eggs
- Zinc: essential for testosterone production and sperm development
These earned top marks based on evidence from randomized controlled trials. For CoQ10 specifically, studies in men used doses up to 300 milligrams per day. A good men’s fertility multivitamin will contain most of these, but check the label rather than assuming.
Inositol for PCOS
If you have polycystic ovary syndrome, inositol deserves special attention. PCOS often involves insulin resistance, which disrupts ovulation. Myo-inositol, a type of B-vitamin-like compound, helps improve insulin sensitivity and restore more regular ovulatory cycles.
The most studied formulation combines myo-inositol with D-chiro-inositol in a 40:1 ratio, which mirrors the natural ratio found in the body. This specific ratio has shown the most consistent results in clinical studies. Getting the ratio wrong matters: too much D-chiro-inositol can actually reduce the body’s ability to absorb myo-inositol, which is the form that does most of the heavy lifting in ovarian tissue. Many supplements marketed for PCOS already use the 40:1 ratio, but it’s worth confirming on the label.
What to Avoid
Not all vitamins are safe in large doses during the preconception window. Preformed vitamin A (retinol) is the main one to watch. The CDC has flagged that women who could become pregnant should avoid supplements containing more than 8,000 IU of vitamin A per day. Doses of 25,000 IU or higher during pregnancy have been associated with birth defects affecting the skull, heart, spine, and central nervous system. Since organ formation happens very early, often before a missed period, the risk window starts before you’d even know you’re pregnant.
Beta-carotene, the plant-based form of vitamin A found in carrots and sweet potatoes, does not carry this risk because your body only converts what it needs. The concern is specifically with preformed vitamin A from supplements or animal-derived sources. Check your prenatal vitamin to make sure its vitamin A comes from beta-carotene or is within the safe range.
Putting It All Together
A quality prenatal vitamin covers the basics: folic acid, vitamin D, iron, and iodine. From there, you can layer on targeted supplements based on your situation. CoQ10 makes the most sense if you’re over 35 or have been told about diminished ovarian reserve. Inositol is specifically useful for PCOS. Omega-3s benefit nearly everyone who doesn’t eat fish regularly. And your partner should be taking his own fertility-supporting nutrients for at least three months before you start trying, since sperm take about 74 days to fully develop.
Starting supplements one to three months before conception gives your body time to build up nutrient stores and gives any improvements in egg or sperm quality time to take effect. This isn’t just about the moment of conception. It’s about the nutritional environment your body provides during the earliest, most critical days of embryonic development.