3 supplements for male fertility: what the research actually shows

About 15% of couples trying to conceive don’t achieve pregnancy within a year. Male factors contribute to roughly half of all infertility cases, either alone or in combination with female factors [1]. This has created a market for supplements claiming to improve sperm quality, but how much of this is backed by actual research?

I’ve gone through the clinical literature on the three most commonly discussed supplements for male fertility: zinc, coenzyme Q10, and omega-3 fatty acids. Here’s what the evidence actually supports.

How common is male infertility?

One in six couples will experience difficulty conceiving at some point. In about 40-50% of cases, male factors play a role [2]. The causes range from hormonal imbalances and genetic conditions to varicocele (enlarged veins in the scrotum), infections, and lifestyle factors like smoking, obesity, and excessive alcohol consumption.

In more than 30% of male infertility cases, doctors can’t identify a specific cause. The semen analysis shows abnormalities (low sperm count, poor motility, or abnormal morphology), but there’s no obvious explanation. This is called idiopathic male infertility, and it’s where supplements are most commonly tried.

Before reaching for any supplement, it’s worth getting properly evaluated. Conditions like chronic prostatitis or benign prostatic hyperplasia can sometimes affect fertility and are treatable. Lifestyle modifications often help too: quitting smoking, reducing alcohol, maintaining a healthy weight, and avoiding excessive heat to the testicles (hot tubs, laptops on laps, tight underwear).

1. Zinc

Zinc is the supplement patients ask about most often, which makes sense given its biological role. The prostate gland and seminal fluid contain unusually high concentrations of zinc, and the mineral is involved in testosterone production and sperm development.

What the research shows

Several studies have found that men with infertility tend to have lower zinc levels in their seminal plasma compared to fertile men [3]. A 2020 meta-analysis pooling data from 20 studies found that zinc supplementation improved sperm concentration and motility, though the improvements were modest [4].

One randomised trial gave 220 mg of zinc sulphate daily for three months to men with low sperm counts. The treatment group showed improvements in sperm count, progressive motility, and fertilisation capacity compared to placebo [5].

My honest take

The zinc story is more convincing than most supplement claims for male fertility. There’s a plausible biological mechanism, observational studies showing deficiency correlates with infertility, and some randomised controlled trials showing benefit.

The catch? Most studies are small (under 100 participants), short-term (one to three months), and measure semen parameters rather than actual pregnancy rates. Improving sperm count on paper doesn’t necessarily translate to more babies. Also, zinc deficiency is relatively uncommon in well-nourished populations. If you’re eating adequate protein from meat, poultry, and seafood, you’re probably not zinc deficient.

The NHS recommends adult men get 9.5 mg of zinc daily [6]. Good food sources include oysters (by far the richest source), beef, crab, fortified cereals, and pumpkin seeds. If you do supplement, don’t exceed 40 mg daily long-term, as high doses can interfere with copper absorption.

For more detail on zinc supplementation, see our zinc article.

2. Coenzyme Q10 (CoQ10)

CoQ10 is an antioxidant that plays a central role in cellular energy production. Sperm cells require substantial energy for motility, and they’re susceptible to oxidative stress damage. This provides the rationale for CoQ10 supplementation.

What the research shows

A 2013 Cochrane review examined antioxidants for male infertility and found evidence that antioxidant supplementation may improve pregnancy rates, though the quality of studies was mixed [7]. CoQ10 specifically has been tested in several trials.

One randomised trial of 228 men with idiopathic infertility found that 200 mg CoQ10 daily for six months improved sperm count and motility compared to placebo [8]. Another study of 60 men found similar improvements after three months of 300 mg daily supplementation.

A 2019 meta-analysis pooling data from six randomised trials concluded that CoQ10 supplementation significantly improved sperm concentration and motility [9]. However, the authors noted substantial variability between studies.

My honest take

The CoQ10 evidence is reasonable but not overwhelming. The studies show improvements in semen parameters, which is encouraging. Some trials have also tracked pregnancy rates and found modest improvements, though these weren’t always statistically significant.

What gives me pause is the variability between studies. Some show substantial benefits, others show minimal effects. This heterogeneity often suggests the true effect is smaller than the most optimistic studies indicate.

CoQ10 has a good safety profile at doses up to 600 mg daily, and it doesn’t interact with many medications. If you’re going to try a fertility supplement, it’s not a bad choice. Typical doses in studies range from 200-400 mg daily for at least three months.

For comprehensive information on CoQ10, including side effects and drug interactions, see our CoQ10 article.

3. Omega-3 fatty acids (fish oil)

Omega-3 fatty acids, particularly DHA and EPA from fish oil, are incorporated into sperm cell membranes and affect their fluidity and function. DHA concentrations are particularly high in sperm, suggesting it plays an important structural role.

What the research shows

Observational studies have found that men who eat more fish or have higher blood levels of omega-3s tend to have better semen quality [10]. This correlation is consistent across multiple populations.

A 2019 randomised trial of 173 infertile men compared fish oil supplementation (1.84 g omega-3 daily) to placebo for 12 weeks. The fish oil group showed improvements in sperm concentration, total sperm count, and morphology [11].

However, a larger 2020 trial of 300 men found no significant difference in semen parameters between omega-3 supplementation and placebo [12]. The inconsistency between these results is frustrating but typical in nutrition research.

My honest take

The omega-3 evidence for male fertility is weaker than I expected given how much it’s promoted. Yes, DHA is structurally important for sperm. Yes, some observational studies show correlations. But the intervention trials are mixed, and the positive ones show fairly modest improvements.

I wouldn’t specifically recommend fish oil for fertility purposes alone. That said, omega-3s have other potential health benefits (cardiovascular, anti-inflammatory), so there’s little downside to taking them if you’re not eating much fish.

If you do supplement, look for products providing at least 1 gram combined EPA and DHA daily. Quality varies considerably between brands.

For detailed information on fish oil supplementation, see our fish oil article.

Other supplements sometimes mentioned

A few other supplements come up in fertility discussions:

Folic acid - There’s some evidence that folic acid combined with zinc may improve semen quality, but folic acid alone doesn’t appear to help. Men trying to conceive sometimes take it anyway since there’s minimal risk and potential benefit for foetal development once pregnancy occurs. See our folic acid article.

Vitamin E - An antioxidant that’s been tested in fertility trials, usually in combination with other antioxidants rather than alone. Results have been inconsistent. See our vitamin E article.

L-carnitine - Plays a role in sperm energy metabolism. Some small trials show modest benefits, but the evidence base is thin.

Selenium - Another antioxidant. A few studies suggest benefit, but high doses can be toxic, so supplementation requires caution.

Bottom line

Of the three main fertility supplements, zinc has the most plausible case. CoQ10 has reasonable supporting evidence. Omega-3s are the weakest of the three despite heavy marketing.

None of these will work miracles. The improvements seen in studies, when present, tend to be modest increases in sperm concentration and motility. Whether these translate to higher pregnancy rates remains uncertain in most cases.

If you’re experiencing fertility difficulties, get properly evaluated first. Rule out treatable causes. Address lifestyle factors. Then, if you want to try supplements, zinc and CoQ10 are reasonable options with acceptable safety profiles. Give them at least three months, as that’s roughly how long sperm development takes.

Don’t spend a fortune on proprietary fertility blends. The same ingredients are available much cheaper as individual supplements.

Related reading

• Zinc: benefits, side effects, and dosing
• CoQ10: what the research shows
• Fish oil benefits and side effects

References

1. Agarwal A, Mulgund A, Hamada A, Chyatte MR. A unique view on male infertility around the globe. Reprod Biol Endocrinol. 2015;13:37. PMID: 25928197

2. Kumar N, Singh AK. Trends of male factor infertility, an important cause of infertility: A review of literature. J Hum Reprod Sci. 2015;8(4):191-196. PMID: 26752853

3. Zhao J, Dong X, Hu X, et al. Zinc levels in seminal plasma and their correlation with male infertility: A systematic review and meta-analysis. Sci Rep. 2016;6:22386. PMID: 26932683

4. Fallah A, Mohammad-Hasani A, Colagar AH. Zinc is an Essential Element for Male Fertility: A Review of Zn Roles in Men’s Health, Germination, Sperm Quality, and Fertilization. J Reprod Infertil. 2018;19(2):69-81. PMID: 30009140

5. Omu AE, Dashti H, Al-Othman S. Treatment of asthenozoospermia with zinc sulphate: andrological, immunological and obstetric outcome. Eur J Obstet Gynecol Reprod Biol. 1998;79(2):179-184. PMID: 9720837

6. NHS. Vitamins and minerals - Zinc. https://www.nhs.uk/conditions/vitamins-and-minerals/others/

7. Showell MG, Mackenzie-Proctor R, Brown J, Yazdani A, Stankiewicz MT, Hart RJ. Antioxidants for male subfertility. Cochrane Database Syst Rev. 2014;(12):CD007411. PMID: 25504418

8. Safarinejad MR. Efficacy of coenzyme Q10 on semen parameters, sperm function and reproductive hormones in infertile men. J Urol. 2009;182(1):237-248. PMID: 19447425

9. Lafuente R, González-Comadrán M, Solà I, et al. Coenzyme Q10 and male infertility: a meta-analysis. J Assist Reprod Genet. 2013;30(9):1147-1156. PMID: 23912751

10. Attaman JA, Toth TL, Furtado J, Campos H, Hauser R, Chavarro JE. Dietary fat and semen quality among men attending a fertility clinic. Hum Reprod. 2012;27(5):1466-1474. PMID: 22416013

11. Safarinejad MR. Effect of omega-3 polyunsaturated fatty acid supplementation on semen profile and enzymatic anti-oxidant capacity of seminal plasma in infertile men with idiopathic oligoasthenoteratospermia: a double-blind, placebo-controlled, randomised study. Andrologia. 2011;43(1):38-47. PMID: 21219381

12. Hosseini B, Nourmohamadi M, Hajipour S, et al. The Effect of Omega-3 Fatty Acids, EPA, and/or DHA on Male Infertility: A Systematic Review and Meta-Analysis. J Diet Suppl. 2019;16(2):245-256. PMID: 29451828