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Supplements for Oligospermia: Sperm Counts, Pregnancy Odds, and What to Skip

Supplements for oligospermia (a low sperm count) can shift semen test results, but none has been shown to raise the outcome that matters, a baby. Folic acid plus zinc did not raise live births in a trial of 2,370 couples (grade A), and two antioxidant blends did no better than placebo (grade B). CoQ10 and L-carnitine improved sperm movement (grade B). A semen analysis and a urologist's exam come first.

Published How we grade evidenceEditorial policy

The short version

  • Folic acid plus zinc: no more live births in 2,370 couples. Grade A (Schisterman 2020; Michaelsen 2025). Sperm counts: no change in that trial or a 2023 meta-analysis, a small gain in a 2025 one. Grade B (Li 2023).
  • Antioxidant blends: no rise in pregnancies or live births in the two biggest placebo trials. Grade B (Steiner 2020; de Ligny 2025).
  • CoQ10: better sperm movement, and in some analyses more sperm; effect on pregnancy unclear. Grade B (Bakri 2026; Michaelsen 2025).
  • L-carnitine: better movement and shape, but not more sperm. Grade B (Khaw 2020).
  • Selenium, vitamins E and C, omega-3, NAC, ashwagandha, tribulus: small or few trials, mostly semen results only. Grade C (Michaelsen 2025; Ambiye 2013; Sanagoo 2019).
  • Shilajit: one study, with no comparison group. Grade D (Biswas 2010).

Oligospermia means too few sperm in the semen; one large trial used 15 million per milliliter (mL) or fewer as its cut-off (Steiner 2020). A male factor plays a part in 40% to 50% of couples who can't conceive, so the man's history and a semen analysis belong in the first round of tests (ACOG 2019).

Sperm take about 72 days to form, so trials ran supplements for 3 to 6 months (de Ligny 2025; Steiner 2020). The test that matters is a pregnancy that ends in a birth. Many small trials report only semen numbers, and those can improve while births stay the same.

Do folic acid and zinc raise sperm count?

Grade A for live births: no rise. The largest trial enrolled 2,370 couples heading for fertility treatment. For 6 months the men took a placebo or a daily dose of 5 mg folic acid with 30 mg zinc. Live births were 34% against 35%. Sperm concentration, movement and shape did not differ, and the supplement group ended with a little more DNA damage in their sperm (29.7% against 27.2%) (Schisterman 2020).

Grade B for sperm count: mixed. An earlier Dutch trial in 103 subfertile men had found a 74% rise in total normal sperm count with the combination (Wong 2002), but a 2023 meta-analysis found that folic acid plus zinc changed neither sperm concentration, movement and shape nor pregnancy rates; folic acid alone slightly improved movement (Li 2023). A 2025 review of placebo trials lasting 12 weeks or more found small concentration gains with zinc and with folic acid, and no effect of any supplement on pregnancy or live birth (Michaelsen 2025). Our zinc page shows sperm movement and count, and our folic acid page sperm count, as "improves" from the 2023 review; it found no change in either for the pair, and no count change for folic acid alone.

Do antioxidant blends lead to more pregnancies?

Grade B. Not in the best trials. A US trial enrolled 174 men whose semen showed a low count, weak movement, odd shapes or DNA damage. A seven-ingredient antioxidant pill (vitamin C, vitamin E, lycopene, selenium, zinc, folic acid and L-carnitine), taken for 3 to 6 months, brought no gain in semen results. Live births came to 15% on the pill and 24% on placebo, not a clear difference (Steiner 2020).

A Dutch trial at 21 clinics gave 1,171 men a daily tablet of betaine, L-cystine, niacin, zinc, B vitamins and folic acid, or a placebo, for 6 months. Ongoing pregnancies were 33.8% against 37.5%, and in months 4 to 6 they were lower on the supplement (15.5% against 21.5%) (de Ligny 2025).

The Cochrane review found higher odds of a live birth in the 12 trials that reported it (1,283 men), but rated that evidence very low. In the 8 trials at lower risk of bias (827 men), the gain was no longer clear (de Ligny 2022). A 2025 review of placebo trials lasting at least 12 weeks found no supplement that raised pregnancy or live birth (Michaelsen 2025).

Does CoQ10 help sperm count?

Grade B for semen results. Coenzyme Q10 is an antioxidant made in the body. Pooling randomized CoQ10 trials in men whose infertility had no known cause, a 2026 meta-analysis found about 10 million more sperm per mL and a 4.95 percentage-point gain in sperm movement (Bakri 2026). The 2025 review saw a gain in movement only (Michaelsen 2025).

Grade C for pregnancy. The 2026 analysis reported higher pregnancy odds, while an earlier one of 3 trials (296 men) found no rise in pregnancies and no trial that counted births (Bakri 2026; Lafuente 2013). One of the largest single trials, 300 mg a day by mouth in 212 men for 26 weeks, carries a 2023 expression of concern from its journal. It reported better sperm density and movement (Safarinejad 2009).

Does L-carnitine improve sperm?

Grade B for movement. L-carnitine is a natural antioxidant found in high amounts in the fluid where sperm mature. Across 8 randomized trials, carnitines improved sperm movement and shape but not sperm concentration (Khaw 2020). Not every trial agreed: 21 men taking 2,000 mg of L-carnitine and 1,000 mg of acetyl-L-carnitine by mouth daily for 24 weeks saw no gain (Sigman 2006).

Grade C for pregnancy. The 5 trials in that review that counted pregnancies showed no clear effect (Khaw 2020), and pooling carnitine, CoQ10 and selenium trials gave 16.2% against 11.2%, not a significant difference (Sharma 2022). Our oligospermia page says carnitine improved fertility; we grade the pregnancy effect C because these reviews found no clear rise.

Do selenium, vitamin E or vitamin C help?

Grade C. In 69 Scottish men with poor sperm movement, selenium, alone or with vitamins A, C and E, for 3 months raised movement but not numbers, and 5 men on it fathered a child against none on placebo (Scott 1998). A trial in 468 men of 200 mcg of selenium, 600 mg of NAC or both, which reported gains in every semen measure, also has a 2023 expression of concern (Safarinejad 2009).

For vitamin E and vitamin C, a 2022 meta-analysis found small gains in movement and numbers, and more pregnancies with vitamin E (relative risk 1.86), on moderate to low quality evidence (Zhou 2022). Yet 1,000 mg of vitamin C with 800 mg of vitamin E for 56 days changed nothing in 31 men (Rolf 1999), and the 2025 review found no semen gain from vitamin E (Michaelsen 2025).

Does omega-3 fish oil help?

Grade C. Pooling 3 trials (290 men), omega-3 fatty acids improved sperm movement but not concentration, with results that varied widely (Hosseini 2019). The 2025 review found no semen gain from omega-3 (Michaelsen 2025).

Does ashwagandha raise sperm count?

Grade C. In one placebo-controlled pilot trial, 46 men with fewer than 20 million sperm per mL took 675 mg a day of ashwagandha root extract, in three doses, or a placebo for 90 days. On ashwagandha, counts rose from 9.59 to 25.61 million per mL, with little change on placebo (Ambiye 2013). A review found that this was the only randomized trial, and judged the data too limited to be robust (Durg 2018).

Does tribulus help sperm count?

Grade C. A 2019 review found 7 studies of tribulus in men with unexplained infertility; 6 reported better sperm numbers, movement or shape (Sanagoo 2019). The one that found nothing gave 30 men 750 mg a day for 3 months, with no placebo group, and saw no change in testosterone or semen (Roaiah 2017). The abstract of the one placebo trial in low sperm count reports only a combined symptom score (Sellandi 2012). Across 52 studies of supplements sold to raise testosterone, tribulus among them, most did not raise it (Morgado 2024).

Do NAC or vitamin D help?

Grade C. Pooling 3 trials (431 men), daily NAC by mouth improved concentration, volume, movement and shape against placebo (Zhou 2021). For vitamin D, a 2026 review found small semen gains but no effect on pregnancy or live birth (Zhang 2026).

What we'd skip

  • Shilajit. Its only study had no comparison group, and 28 of 35 men finished it (Biswas 2010). Our database grades it C; without a control group we grade it D.
  • Testosterone and anabolic steroids. They lower sperm production and can stop it altogether (Crosnoe 2013; Esposito 2023). More on this below.
  • Vitamin E at 400 IU a day for years. In a trial of 35,533 men aged 50 or 55 and over, 400 IU a day raised prostate cancer risk (Klein 2011).

Safety and interactions

  • Stomach upset. Folic acid plus zinc caused more belly pain (6% against 3%), nausea and vomiting than placebo (Schisterman 2020). Across 16 antioxidant trials, mild stomach discomfort was more common than on placebo (de Ligny 2022).
  • Upper limits for adults: 40 mg of zinc a day from food and supplements (NIH ODS), 1,000 mcg of folic acid, counting fortified foods as well as pills (NIH ODS), 400 mcg of selenium (NIH ODS) and 1,000 mg of vitamin E from supplements (NIH ODS). The large trial's 5 mg of folic acid is five times that limit. Fertility blends often stack these, so add up every label.
  • Vitamin E. In healthy older men, 400 IU a day of synthetic vitamin E raised prostate cancer risk by about 17%, or 1.6 more cases per 1,000 men a year (Klein 2011). Large doses with warfarin or antiplatelet medicines can raise bleeding risk (NIH ODS).
  • Zinc can interact with quinolone and tetracycline antibiotics and with penicillamine (NIH ODS). CoQ10 might affect warfarin, a blood thinner, and insulin, according to NCCIH.
  • Ashwagandha. Case reports describe liver injury with jaundice 2 to 12 weeks after starting; in 5 people, none had liver failure (Björnsson 2020). Stop it and get checked if your skin or eyes turn yellow. NCCIH says it might interact with medicines for diabetes, blood pressure and the thyroid, sedatives, anti-seizure drugs and immunosuppressants (NCCIH).
  • Testosterone and steroids. Anabolic steroids can shrink the testicles and leave no sperm in the semen. Sperm usually recover within 4 months of stopping, but it can take up to 3 years (Esposito 2023). Prescribed testosterone also cuts sperm production; in male-contraception studies, most men's sperm returned within a year of stopping (Crosnoe 2013).
  • No interaction studies were found for carnitine or shilajit.

When to see a doctor

  • No pregnancy after 12 months of trying, or after 6 months if the woman is over 35. Both partners should be checked, and the man's first test is a semen analysis (ACOG 2019).
  • Swollen veins in the scrotum (a varicocele). Repairing one may raise pregnancy rates, though the effect on births is uncertain (Persad 2021).
  • Signs of low testosterone, such as low sex drive, erection problems, loss of body hair or small, soft testicles. A doctor can test your hormones and may discuss medicines.
  • A lump, pain or swelling in a testicle: see a doctor soon.
  • If you use testosterone, steroids or "muscle" products, tell the doctor. Don't stop a prescribed medicine on your own; ask the prescriber or pharmacist.

If you are under 18, ask a clinician. If your partner is pregnant or trying to conceive, her supplements are a question for her doctor or midwife.

FAQ

What is the best supplement for low sperm count? None has been shown to raise births. CoQ10 and L-carnitine have the most support for better sperm movement (grade B), while folic acid with zinc did not help in a 2,370-couple trial (grade A).

How long do supplements take to change a semen test? Sperm take about 72 days to form, so trials ran supplements for 3 to 6 months before retesting.

Can supplements replace fertility treatment? No. In the trials, supplements were added to standard fertility care, and the largest ones found no extra pregnancies or births.

Does testosterone help sperm count? No. Testosterone and anabolic steroids lower sperm production, and recovery after stopping can take months to years.

Are CoQ10 and L-carnitine safe to take together? No interaction between them was reported in the trials. If you take warfarin or insulin, ask a pharmacist first, because CoQ10 might affect both.

Sources

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