Zinc, Folic Acid and Selenium for Male Fertility: Do These Common Supplements Really Work?

Walk into any pharmacy and ask for a fertility supplement for men. There is a good chance the bottle you get will list three names on the label: zinc, folic acid and selenium. They are cheap. They are easy to find. And for years they have been called "the basics" of male fertility.

But here is the twist. In 2020, a very large and carefully run trial tested two of them, zinc and folic acid, in more than two thousand men. The result surprised many doctors. It did not show the benefit people had hoped for.

So what should a man trust? The older small studies that looked good, or the big trial that did not? In this article, I will walk you through both sides in plain words. We will look at what these three nutrients do in the body, what the research really says about zinc for male fertility, folic acid and sperm quality, and selenium for sperm motility, and how to make a sensible decision.

In Article 1 we covered CoQ10, and in Article 2 we covered L-carnitine. Those two work mostly around the sperm's energy system. Zinc, folic acid and selenium are different. They are everyday vitamins and minerals, and your body needs them for many jobs, not just for fertility.

What Do These Three Nutrients Do?

Zinc

Zinc is a mineral that your body needs for growth, healing, and a healthy immune system. It is also found in high amounts in the male reproductive system. Doctors believe it plays a part in how sperm are made and how they develop. You can get zinc from meat, shellfish (oysters are especially rich), beans, lentils, seeds and nuts.

Folic acid (folate)

Folate is one of the B vitamins. It helps the body make and repair DNA, the genetic material inside every cell. Since sperm are being made all the time, and each one carries DNA, it is easy to see why researchers wondered about folate. Folic acid is the man-made form used in supplements. Folate is the natural form found in green leafy vegetables, beans, citrus fruits and fortified grains.

Selenium

Selenium is a trace mineral, which means the body needs only a very small amount. It works as part of special proteins that protect cells from oxidative damage. Selenium is found in Brazil nuts, fish, eggs, meat and some grains. The amount in food varies a lot depending on how much selenium is in the soil where the crop grew.

Why Would They Matter for Sperm?

A research team behind a big fertility trial explained that folic acid and zinc are two nutrients important in the process of making sperm. They noted that both are cheap and widely available, and that they may affect the structure of sperm DNA. Small trials and observational studies had suggested a possible benefit, even though the results were not consistent.

Selenium is a little different. A review of the topic explained that animals with a selenium shortage develop poor sperm movement and changes in the middle part of the sperm, where the energy machinery sits. It also found that most studies show a positive link between selenium levels in blood and semen and some sperm quality measures, particularly motility.

As always, a link is not proof. A nutrient being important for sperm does not mean that taking extra will make a healthy difference. That is why we need proper trials.

The Early Promise

Several older studies gave hope. One often-quoted randomized trial gave men either folic acid (5 mg) with zinc sulfate (66 mg), each on its own, or a placebo, for six months. It included 94 men with fertility problems and 99 fertile men. According to the description of this study in a later trial protocol, only the folic acid and zinc combination led to a notable rise in sperm count, about 74 percent in the men with fertility problems.

Other reviews added to the optimism:

• A 2018 meta-analysis of randomized trials in the journal Advances in Nutrition found that selenium and zinc raised total sperm motility by small amounts. The reported gains were about 3 percentage points for selenium and about 7 for zinc. Selenium also gave a small boost to sperm shape.

• A 2019 review in Reproductive BioMedicine Online, covering 18 placebo-controlled trials, identified promising data for the zinc and folic acid combination, and suggested that selenium, alone or with N-acetyl-cysteine, may help. The authors added that the number of studies and patients was small and that better trials were needed.

• A newer review of dietary supplement trials lasting at least 12 weeks found that zinc and folic acid improved sperm concentration in some analyses, while selenium improved motility.

That was the picture for years: not perfect, but encouraging.

The Big Trial That Changed the Conversation

In 2020, researchers published the Folic Acid and Zinc Supplementation Trial, often called FAZST, in the medical journal JAMA. It was funded by a US government health institute and run at four fertility centers.

Why does it matter so much? Because of its size and design.

• 2,370 men were randomly chosen to receive either a daily supplement or a placebo.

• The supplement contained 5 mg of folic acid and 30 mg of zinc.

• Treatment lasted six months.

• Neither the men nor the researchers knew who got which pill (this is called double-blind).

• The men were partners in couples getting infertility treatment.

The result? The supplements did not improve semen quality, and they did not raise the couples' live birth rates. Sperm concentration, motility, shape, volume and total motile sperm count were not meaningfully different between the two groups after six months.

There was one more finding worth knowing. The men taking folic acid and zinc actually had a slightly higher level of sperm DNA fragmentation than the placebo group (about 29.7 percent compared with 27.2 percent). Sperm DNA fragmentation means the genetic material in the sperm is broken or damaged. The difference was small, but it surprised the researchers. One of the study's co-authors also said, in a university press release, that the trial showed that nutraceuticals like these did not improve the chance of pregnancy and could cause unwanted side effects.

That is a strong message. It does not mean zinc and folic acid are bad nutrients. It means that, in this group of men, extra amounts did not help.

What Do the Combined Reviews Say Now?

After the big trial, a 2023 systematic review and meta-analysis in the journal Heliyon examined folic acid and folic acid plus zinc. It found no significant improvement in sperm characteristics with the folic acid plus zinc combination. Interestingly, folic acid on its own showed possible benefit for sperm motility and for outcomes in IVF and ICSI treatments (two types of assisted reproduction). The authors suggested folic acid alone may be worth looking at more closely, but this is still early.

So here is a fair way to put it: the zinc and folic acid combination, which looked promising in small studies, did not hold up in the largest and best-designed trial so far.

What About Selenium?

Selenium has a somewhat better story, but it is still not settled.

A 2020 review in the journal Hormones looked at studies in humans and animals. The authors found that the evidence was limited in amount and of somewhat low quality. Still, it suggested that selenium supplements at less than 200 micrograms a day are possibly helpful for men, mostly by improving sperm motility. They said well-designed trials were needed.

A 2025 comprehensive review of selenium and selenoproteins in idiopathic male infertility reached a similar view. It noted that selenium levels in semen and blood are linked with sperm quality, particularly motility, and that most available clinical trials support a possible benefit from supplementation.

But not every trial agrees. A single-blind randomized trial of men with idiopathic infertility tested a combination of selenium, vitamin E and folic acid. The researchers found no significant differences between the groups in semen volume, sperm concentration, total motility, progressive motility or normal shape. And the earlier mentioned meta-analysis on 20 trials of carnitine, CoQ10 and selenium found no clear difference in pregnancy or live birth rates, even though semen tests improved.

In short, selenium looks like it may help sperm movement in some men, especially those who are low in selenium to begin with. But the proof that it leads to babies is thin.

What Do the Biggest Recent Reviews Say?

Two of the newest large reviews both lean cautious. One analysis of dietary supplements in male infertility, which only included trials that ran at least 12 weeks, concluded that there was no convincing proof that any supplement helps. And the 2026 meta-analysis of 41 randomized trials in the journal Andrology repeated a point we have seen in every article of this series: we still do not know whether better semen results turn into more pregnancies.

This does not mean nothing works. It means we need better research, with larger groups, clearer measures, and live births as the main result.

Why Are the Results So Mixed?

If you feel puzzled, you are not alone. Here are the main reasons studies disagree:

Different starting points. A man who is truly low in zinc or selenium may benefit from a supplement. A man with normal levels may not. Many trials did not check this first.

Different doses. The older trials used higher zinc doses (66 mg) than the large trial (30 mg). The big trial might have used a lower dose, though higher doses carry their own risks.

Different groups of men. Some trials enrolled men with very poor sperm counts. FAZST enrolled men whose partners were starting fertility treatment, a mixed group.

Different outcomes. Some studies measured sperm tests. Others measured pregnancy. FAZST measured live birth, the hardest and most meaningful target.

Study size. Small trials can give exciting results by chance. Large trials tend to be more reliable.

When a big, well-run trial disagrees with several small ones, doctors usually give more weight to the big one. That is the main reason zinc and folic acid are viewed more cautiously today than they were ten years ago.

Can Too Much Be Harmful?

Yes, and this is the part supplement labels rarely stress.

• Too much zinc can cause nausea, stomach pain and vomiting. Over a long time, large amounts can lower the body's copper and cause other problems.

• Too much selenium can be toxic. Signs include hair loss, brittle nails, stomach upset and a garlic-like smell on the breath. The gap between a helpful amount and a harmful amount is smaller than most people think.

• Folic acid at high doses can hide a vitamin B12 shortage, and, as FAZST showed, extra supplements are not automatically harmless for sperm.

• Stacking products. Many fertility blends, multivitamins and energy mixes contain all three nutrients. If you take several, you can easily go over safe limits without realizing it.

This is why it is best to check your actual levels and talk to a doctor before starting high-dose supplements.

Food First: A Smarter Starting Point

Before you reach for a bottle, look at your plate. A balanced diet can supply good amounts of all three nutrients:

• Zinc: meat, fish, shellfish, eggs, beans, lentils, pumpkin seeds, nuts, whole grains

• Folate: leafy greens such as spinach, beans, lentils, citrus fruits, avocado, fortified grains

• Selenium: fish, eggs, poultry, whole grains, and Brazil nuts (even a small number gives a lot)

A diet rich in vegetables, fruits, nuts, fish and whole grains also gives you natural antioxidants and healthy fats, which other studies link to better sperm quality. Food does not come with the risk of overdoing a single nutrient.

Lifestyle Matters Too

No supplement can cancel out harmful habits. If you want to improve sperm quality naturally, put these first:

• Stop smoking. It is among the clearest causes of oxidative stress in the semen.

• Limit alcohol and avoid recreational drugs.

• Keep a healthy weight and stay active.

• Avoid too much heat around the groin, like very hot baths or long hours with a laptop on the lap.

• Sleep well and find ways to manage stress.

• See a doctor to check for a varicocele, an infection or a hormone problem, which may need their own treatment.

A Practical Plan

If you are wondering what to do about zinc, folic acid and selenium, here is a simple way to approach it:

1. Start with a semen analysis and a visit to a doctor who knows male infertility.

2. Ask about your nutrient levels and your diet. If you are low in something, correcting it makes sense.

3. Improve your diet first. It is cheap, safe and good for your overall health.

4. If you and your doctor decide to try a supplement, keep the dose within safe limits and avoid stacking products.

5. Give it about three months, which is roughly how long sperm take to renew, then repeat the semen test.

6. Do not delay proper treatment while waiting for a supplement to work, especially if your partner's age is a factor.

Frequently Asked Questions

Does zinc increase sperm count? Some smaller studies and reviews said yes, but the largest trial found no improvement when zinc was taken with folic acid. The evidence is mixed.

Does folic acid improve male fertility? A recent meta-analysis found that folic acid taken alone may help sperm motility and assisted reproduction results, but that conclusion is still early. Combined with zinc, it did not show a clear benefit.

Is selenium good for sperm motility? Several reviews suggest it may help sperm movement at moderate doses, but the quality of the evidence is limited, and not every trial agrees.

Can I take zinc, folic acid and selenium together? Many products combine them, but it is easy to overshoot safe amounts. Check labels carefully and ask your doctor.

Should I take a multivitamin instead? A basic multivitamin may cover your needs without extreme doses, but whether it changes fertility is not proven. Your doctor can advise you.

Final Thoughts

Zinc, folic acid and selenium are real, important nutrients. Your body needs them, and a shortage can harm your health. But for men who already get enough, extra amounts do not appear to be a magic fix for infertility. The biggest trial so far did not support zinc and folic acid for improving sperm quality or live birth. Selenium may help sperm movement, but the evidence is limited.

The smartest path is simple: get checked, eat well, correct any real shortage, and avoid piling on high doses just because a label promises results. If you do try a supplement, do it with medical guidance and measure the outcome with a repeat test.

Disclaimer: This article is for general information only and is not medical advice. Please speak to a qualified doctor before taking any supplement, especially if you have a health condition or take regular medicines.

References

1. Schisterman EF, Sjaarda LA, Clemons T, et al. Effect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial. JAMA. 2020;323(1):35-48. Read the article

2. Folic Acid and Zinc Supplementation Trial (FAZST) study protocol, which also describes the earlier folic acid and zinc sulfate trial. View the protocol

3. University of Utah Health. Zinc, Folic Acid Supplements Fail to Enhance Male Infertility. 2020. Read the press release

4. Effects of folic acid and folic acid plus zinc supplements on the sperm characteristics and pregnancy outcomes of infertile men: A systematic review and meta-analysis. Heliyon. Read the article

5. Salas-Huetos A, Rosique-Esteban N, Becerra-Tomas N, Vizmanos B, Bullo M, Salas-Salvado J. The Effect of Nutrients and Dietary Supplements on Sperm Quality Parameters: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. Advances in Nutrition. 2018;9(6):833-848. Read the article

6. Influence of oral vitamin and mineral supplementation on male infertility: a meta-analysis and systematic review. Reproductive BioMedicine Online. 2019;39(2):269-279. View on PubMed

7. Mintziori G, Mousiolis A, Duntas L. Evidence for a manifold role of selenium in infertility. Hormones. 2020. Read the abstract

8. Impact of selenium and selenoproteins on idiopathic male infertility: a comprehensive review. Read the article

9. The Effect of Daily Intake of Selenium, Vitamin E and Folic Acid on Sperm Parameters in Males with Idiopathic Infertility: A Single-Blind Randomized Controlled Clinical Trial. Read the article

10. The Effect of Dietary Supplements on Male Infertility in Terms of Pregnancy, Live Birth, and Sperm Parameters: A Systematic Review and Meta-Analysis. Read the article

11. Systematic Review and Meta-analysis on Effect of Carnitine, Coenzyme Q10 and Selenium on Pregnancy and Semen Parameters in Couples With Idiopathic Male Infertility. Urology. View the abstract

12. Melhem SJ, et al. Pharmacologic and Nutritional Therapies in Idiopathic Male Infertility: A Systematic Review and Meta-Analysis. Andrology. 2026. Read the article