Male Infertility
Supplements studied for male infertility.
Overview
L-Carnitine and Acetyl-L-Carnitine have medium-strength evidence from 41 combined studies for improving sperm quality, including count, movement, and shape over several months, though effects on pregnancy rates remain uncertain. Selenium may modestly improve sperm numbers and movement but not shape, and its role in combination products is unclear.
Vitamin B9 (Folate) shows mixed results across small studies, with some suggesting increased sperm count but larger trials finding no improvement. Alpha-Lipoic Acid may slightly improve sperm movement and shape without clear pregnancy benefit. The heatmap and evidence reviews below provide a fuller comparison.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Zinc | ★★★★★ | Medium |
| L-Carnitine | ★★★★★ | Medium |
| Acetyl-L-Carnitine | ★★★★★ | Medium |
| Alpha-Lipoic Acid | ★★★★★ | Low |
| Lycopene | ★★★★★ | Low |
| Panax Ginseng | ★★★★★ | Low |
| Multivitamin | ★★★★★ | Low |
| Astaxanthin | ★★★★★ | Low |
| Ashwagandha | ★★★★★ | Low |
| Vitamin B9 (Folate) | ★★★★★ | Very Low / None |
| Selenium | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
11 supplements for and rated at least stars. All purchase bands. No minimum star filter.
Acetyl-L-CarnitineView supplement →
Consider purchase·★★★★★
How we scored this▸
- Taking acetyl-L-carnitine together with L-carnitine (usually 1 gram and 2 grams daily) for 3 to 6 months may help improve sperm movement in men who have trouble with fertility.
- The effects on the number and shape of sperm are unclear.
- It is not certain if these supplements help couples get pregnant, as most studies show mixed results.
- Taking acetyl-L-carnitine by itself is not clearly effective.
- Some studies also looked at supplements that include acetyl-L-carnitine with other vitamins and minerals, and these might improve sperm quality, but it's hard to know which ingredient helps the most.
Browse 15 studies·5 meta-analyses
MetaEffect of antioxidants on semen parameters in men with oligo-astheno-teratozoospermia: a network meta-analysis2024n=2,045
A network meta-analysis of 29 RCTs (2045 men, avg age 33.5) with oligo-astheno-teratozoospermia ranked L-carnitine plus L-acetylcarnitine highest for sperm concentration, progressive motility, and morphology versus placebo.
- Effect
- Benefit
- Population
- Men with oligo-astheno-teratozoospermia
- Participants
- 2,045
- Avg age
- ~34
MetaThe Effect of Antioxidants on Sperm Quality Parameters and Pregnancy Rates for Idiopathic Male Infertility: A Network Meta-Analysis of Randomized Controlled Trials2022n=1,917
A network meta-analysis of 23 RCTs (1917 patients) found L-carnitine ranked first for sperm motility and morphology and ω-3 fatty acids for concentration, but no antioxidant significantly improved pregnancy rate versus placebo.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 1,917
Clinical trialThe Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022n=163
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 450 mg/day
- Population
- Pregnant women
- Participants
- 163
MetaA Meta-Analysis of the Efficacy of L-Carnitine/L-Acetyl-Carnitine or N-Acetyl-Cysteine in Men With Idiopathic Asthenozoospermia2021n=621
A meta-analysis of 7 RCTs (621 men) with asthenozoospermia found L-carnitine/L-acetylcarnitine improved sperm motility and morphology; N-acetylcysteine also improved concentration and ejaculate volume.
- Effect
- Benefit
- Population
- Men with asthenozoospermia
- Participants
- 621
Comparison of 3- and 6-Month Outcomes of Combined Oral L-Carnitine Fumarate and Acetyl-L-Carnitine Therapy, Included in an Antioxidant Formulation, in Patients with Idiopathic Infertility2021n=78
In 78 men with idiopathic infertility, a carnitine-containing antioxidant taken twice daily for 6 months significantly improved sperm concentration, total count, and motility at both 3 and 6 months.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 10 mg
- Population
- Men with idiopathic infertility
- Participants
- 78
MetaL-carnitine and L-acetylcarnitine supplementation for idiopathic male infertility2020n=15
A meta-analysis of 8 RCTs found carnitine supplementation improved total and progressive sperm motility and morphology but not sperm concentration or clinical pregnancy rate.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 15
MetaThe efficacy of combined L-carnitine and L-acetyl carnitine in men with idiopathic oligoasthenoteratozoospermia: A systematic review and meta-analysis2020n=693
A meta-analysis of 7 RCTs (693 men) with oligoasthenoteratozoospermia found combined L-carnitine and L-acetylcarnitine increased forward motility, total motile sperm, and pregnancy rate versus placebo.
- Effect
- Benefit
- Population
- Men with oligoasthenoteratozoospermia
- Participants
- 693
RCTDouble-blind, randomised, placebo-controlled trial on the effect of L-carnitine and L-acetylcarnitine on sperm parameters in men with idiopathic oligoasthenozoospermia2019n=125
An RCT in 175 men aged 19–44 with oligoasthenozoospermia found Proxeed Plus (L-carnitine plus L-acetylcarnitine with micronutrients) for 6 months improved progressive motility, vitality, and reduced sperm DNA fragmentation versus placebo.
- Effect
- Benefit
- Dose
- 10 mg
- Population
- Men with oligoasthenozoospermia
- Participants
- 125
- Ages
- 19–44
RCTSemen quality in patients with Chlamydia trachomatis genital infection treated concurrently with prulifloxacin and a phytotherapeutic agent2012n=109
In 206 men with Chlamydia-associated oligoasthenoteratozoospermia, 6 months of FERTIMEV (L-arginine, L-carnitine, acetyl-L-carnitine, ginseng) plus prulifloxacin improved sperm concentration and motility more than antibiotic alone.
- Effect
- Benefit
- Duration
- 14 days
- Dose
- 600 mg/day
- Population
- Men with chronic prostatitis
- Participants
- 109
RCT[Treatment with carnitine, acetyl carnitine, L-arginine and ginseng improves sperm motility and sexual health in men with asthenozoospermia]2010n=180
An RCT in 180 men with asthenozoospermia found treatment with carnitine, acetylcarnitine, L-arginine, and ginseng significantly improved progressive sperm motility and sexual satisfaction versus no treatment.
- Effect
- Benefit
- Population
- Men with asthenozoospermia
- Participants
- 180
Clinical trial[Clinical efficacy of combined L-carnitine and acetyl-L-carnitine on idiopathic asthenospermia]2008n=30
A trial in 25 men with idiopathic asthenospermia found combined L-carnitine and acetyl-L-carnitine for 3 months significantly improved sperm vitality, grade a+b motility, and total sperm count.
- Effect
- Benefit
- Duration
- 3 months
- Population
- Men with asthenospermia
- Participants
- 30
RCTPlacebo-controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-acetylcarnitine in men with idiopathic asthenozoospermia2005n=59
In 59 men with asthenozoospermia, 6 months of L-carnitine, acetyl-L-carnitine, or combined therapy increased sperm motility and seminal antioxidant capacity, with acetyl-L-carnitine showing the strongest effect.
- Effect
- Benefit
- Dose
- 3 g/day
- Population
- Men with asthenozoospermia
- Participants
- 59
- Ages
- 20–40
RCTA placebo-controlled double-blind randomized trial of combined L-carnitine and L-acetyl-carnitine treatment in men with asthenozoospermia2004n=56
In 56 infertile men with oligo-astheno-teratozoospermia, combined L-carnitine 2 g/day and acetyl-L-carnitine 1 g/day for 6 months significantly increased sperm motility, especially in men with lower baseline motile sperm counts.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 2 g/day
- Population
- Men with asthenozoospermia
- Participants
- 56
- Ages
- 20–40
RCTCinnoxicam and L-carnitine/acetyl-L-carnitine treatment for idiopathic and varicocele-associated oligoasthenospermia2004
In men with idiopathic or varicocele-associated oligoasthenospermia, L-carnitine plus acetyl-L-carnitine with cinnoxicam raised pregnancy rates to 38.0% versus 21.8% with carnitine alone and 1.7% with placebo over 6 months.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 2 g/day
- Population
- Pregnant women
RCTAntioxidant treatment with carnitines is effective in infertile patients with prostatovesiculoepididymitis and elevated seminal leukocyte concentrations after NSAID treatment2002n=30
An RCT in 98 infertile men with prostatovesiculoepididymitis found carnitines after 2 months of NSAIDs produced the greatest reduction in seminal reactive oxygen species and greatest gains in sperm motility.
- Effect
- Benefit
- Duration
- 4 months
- Population
- Pregnant women
- Participants
- 30
L-CarnitineView supplement →
Consider purchase·★★★★★
How we scored this▸
- Research suggests that L-carnitine may help improve sperm quality in men with infertility.
- Doses of 1–3 grams per day, sometimes taken with acetyl-L-carnitine, have been shown in many studies to increase sperm count, movement, and shape over several months.
- However, it is still unclear if this actually leads to higher chances of pregnancy.
- One study found a benefit when both L-carnitine and acetyl-L-carnitine were taken together, but most research does not show clear effects on pregnancy rates.
- Some studies also suggest that L-carnitine, especially when combined with other nutrients like vitamins, minerals, and antioxidants (such as in products like Proxeed Plus), may further improve sperm quality.
- Combinations have sometimes been linked to higher pregnancy rates, but it is difficult to know whether the benefit comes from L-carnitine itself or the mix of ingredients.
Browse 26 studies·7 meta-analyses
MetaMeta-analysis of the efficacy and safety of L-carnitine and N-acetylcysteine monotherapy for male idiopathic infertility2025
A meta-analysis of 7 RCTs found that L-carnitine and N-acetylcysteine monotherapy each improved sperm concentration, motility, and morphology in men with idiopathic infertility; L-carnitine also raised serum testosterone.
- Effect
- Benefit
- Population
- Infertility patients
MetaEffect of antioxidants on semen parameters in men with oligo-astheno-teratozoospermia: a network meta-analysis2023n=2,045
A network meta-analysis of 29 RCTs (2045 men, avg age 33.5) with oligo-astheno-teratozoospermia ranked L-carnitine plus L-acetylcarnitine highest for sperm concentration, progressive motility, and morphology versus placebo.
- Effect
- Benefit
- Population
- Men with oligo-astheno-teratozoospermia
- Participants
- 2,045
- Avg age
- ~34
MetaEffectiveness of Nutritional Therapies in Male Factor Infertility Treatment: A Systematic Review and Network Meta-analysis2023n=94
A network meta-analysis of 69 studies (94 arms) in infertile men found L-carnitine with micronutrients ranked highest for improving sperm quality and pregnancy rates (RR 3.60 vs placebo).
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 94
MetaThe Effect of Antioxidants on Sperm Quality Parameters and Pregnancy Rates for Idiopathic Male Infertility: A Network Meta-Analysis of Randomized Controlled Trials2022n=1,917
A network meta-analysis of 23 RCTs (1917 patients) found L-carnitine ranked first for sperm motility and morphology and ω-3 fatty acids for concentration, but no antioxidant significantly improved pregnancy rate versus placebo.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 1,917
Clinical trialThe Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022n=163
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 10 mg
- Population
- Pregnant women
- Participants
- 163
MetaA Meta-Analysis of the Efficacy of L-Carnitine/L-Acetyl-Carnitine or N-Acetyl-Cysteine in Men With Idiopathic Asthenozoospermia2021n=621
A meta-analysis of 7 RCTs (621 men) with asthenozoospermia found L-carnitine/L-acetylcarnitine improved sperm motility and morphology; N-acetylcysteine also improved concentration and ejaculate volume.
- Effect
- Benefit
- Population
- Men with asthenozoospermia
- Participants
- 621
Comparison of 3- and 6-Month Outcomes of Combined Oral L-Carnitine Fumarate and Acetyl-L-Carnitine Therapy, Included in an Antioxidant Formulation, in Patients with Idiopathic Infertility2021n=78
In 78 men with idiopathic infertility, a carnitine-containing antioxidant taken twice daily for 6 months significantly improved sperm concentration, total count, and motility at both 3 and 6 months.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 10 mg
- Population
- Men with idiopathic infertility
- Participants
- 78
Metal-carnitine and l-acetylcarnitine supplementation for idiopathic male infertility2020n=15
A meta-analysis of 8 RCTs found carnitine supplementation improved total and progressive sperm motility and morphology but not sperm concentration or clinical pregnancy rate.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 15
MetaThe efficacy of combined l-carnitine and l-acetyl carnitine in men with idiopathic oligoasthenoteratozoospermia: A systematic review and meta-analysis2020n=693
A meta-analysis of 7 RCTs (693 men) with oligoasthenoteratozoospermia found combined L-carnitine and L-acetylcarnitine increased forward motility, total motile sperm, and pregnancy rate versus placebo.
- Effect
- Benefit
- Population
- Men with oligoasthenoteratozoospermia
- Participants
- 693
RCTDouble-blind, randomised, placebo-controlled trial on the effect of L-carnitine and L-acetylcarnitine on sperm parameters in men with idiopathic oligoasthenozoospermia2019n=125
An RCT in 175 men aged 19–44 with oligoasthenozoospermia found Proxeed Plus (L-carnitine plus L-acetylcarnitine with micronutrients) for 6 months improved progressive motility, vitality, and reduced sperm DNA fragmentation versus placebo.
- Effect
- Benefit
- Dose
- 10 mg
- Population
- Men with oligoasthenozoospermia
- Participants
- 125
- Ages
- 19–44
RCTDoes L-carnitine therapy add any extra benefit to standard inguinal varicocelectomy in terms of deoxyribonucleic acid damage or sperm quality factor indices: a randomized study2014n=50
A randomized study of 100 men found that adding 750 mg/day oral L-carnitine to varicocelectomy did not significantly improve semen parameters or sperm DNA damage beyond surgery alone.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 750 mg/day
- Population
- Men
- Participants
- 50
RCT[Short-term medication of L-carnitine before intracytoplasmic sperm injection for infertile men with oligoasthenozoospermia]2012n=87
In 129 men with oligoasthenozoospermia, 2 weeks of oral L-carnitine before ICSI improved grade a+b sperm motility and raised available embryo rate (77.5% vs 69.0%) compared with ICSI alone.
- Effect
- Benefit
- Duration
- 2 weeks
- Population
- Pregnant women
- Participants
- 87
RCTSemen quality in patients with Chlamydia trachomatis genital infection treated concurrently with prulifloxacin and a phytotherapeutic agent2012n=206
In 206 men with Chlamydia-associated oligoasthenoteratozoospermia, 6 months of FERTIMEV (L-arginine, L-carnitine, acetyl-L-carnitine, ginseng) plus prulifloxacin improved sperm concentration and motility more than antibiotic alone.
- Effect
- Benefit
- Duration
- 14 days
- Dose
- 600 mg
- Population
- Men with chronic prostatitis
- Participants
- 206
RCT[L-carnitine: safe and effective for asthenozoospermia]2010n=68
In 135 men with asthenozoospermia, 3 months of L-carnitine 2 g/day plus vitamin E raised forward motility (45.4% vs 28.6%) and pregnancy rate (31.1% vs 3.8%) versus vitamin E alone.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 2 g/day
- Population
- Pregnant women
- Participants
- 68
RCTSafety and efficacy of clomiphene citrate and L-carnitine in idiopathic male infertility: a comparative study2010n=32
In 52 men with idiopathic infertility, both L-carnitine and clomiphene citrate improved sperm count and motility over 3 months; L-carnitine increased semen volume while clomiphene improved motility percentage and normal morphology.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 25 mg/day
- Population
- Infertility patients
- Participants
- 32
ObservationalThe significance of microsurgical varicocelectomy in the treatment of subclinical varicocele2010n=93
In 143 men with subclinical varicocele, microsurgical varicocelectomy (60% pregnancy rate) outperformed L-carnitine therapy (34.5%) and observation (18.7%) for natural pregnancy rates.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 93
- Ages
- 1–2
Effect of L-carnitine supplement on semen parameters in men with idiopathic infertility2009
A controlled clinical study in men with idiopathic infertility found that L-carnitine supplementation improved sperm motility and morphology compared with no treatment.
- Effect
- Benefit
- Population
- Infertility patients
RCTEffects of L-carnitine on Infertile Men’s Spermogram; a Randomized Clinical Trial2009
A randomized clinical trial in infertile men reported that L-carnitine supplementation significantly improved sperm motility and overall semen quality compared with control.
- Effect
- Benefit
Systematic reviewEffect of L-carnitine and/or L-acetyl-carnitine in nutrition treatment for male infertility: a systematic review2007
A systematic review of 9 RCTs found L-carnitine and/or acetyl-L-carnitine significantly improved pregnancy rate (OR 4.10), total motility, and forward motility in men with infertility.
- Effect
- Benefit
- Population
- Pregnant women
RCTCarnitine for the treatment of idiopathic asthenospermia: a randomized, double-blind, placebo-controlled trial2006n=12
In 21 men with idiopathic asthenospermia, 24 weeks of L-carnitine 2 g/day plus acetyl-L-carnitine 1 g/day did not significantly increase sperm motility or total motile sperm counts versus placebo.
- Effect
- No Benefit
- Duration
- 24 weeks
- Dose
- 3000 mg/day
- Population
- Infertility patients
- Participants
- 12
RCTPlacebo-controlled double-blind randomized trial on the use of L-carnitine, L-acetylcarnitine, or combined L-carnitine and L-acetylcarnitine in men with idiopathic asthenozoospermia2005n=59
In 59 men with asthenozoospermia, 6 months of L-carnitine, acetyl-L-carnitine, or combined therapy increased sperm motility and seminal antioxidant capacity, with acetyl-L-carnitine showing the strongest effect.
- Effect
- Benefit
- Dose
- 3 g/day
- Population
- Men with asthenozoospermia
- Participants
- 59
- Ages
- 20–40
RCTA placebo-controlled double-blind randomized trial of the use of combined L-carnitine and L-acetyl-carnitine treatment in men with asthenozoospermia2004n=56
In 56 infertile men with oligo-astheno-teratozoospermia, combined L-carnitine 2 g/day and acetyl-L-carnitine 1 g/day for 6 months significantly increased sperm motility, especially in men with lower baseline motile sperm counts.
- Effect
- Benefit
- Dose
- 2 g/day
- Population
- Men with asthenozoospermia
- Participants
- 56
- Ages
- 20–40
RCTCinnoxicam and L-carnitine/acetyl-L-carnitine treatment for idiopathic and varicocele-associated oligoasthenospermia2004
In men with idiopathic or varicocele-associated oligoasthenospermia, L-carnitine plus acetyl-L-carnitine with cinnoxicam raised pregnancy rates to 38.0% versus 21.8% with carnitine alone and 1.7% with placebo over 6 months.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 2 g/day
- Population
- Pregnant women
RCTUse of carnitine therapy in selected cases of male factor infertility: a double-blind crossover trial2003n=86
In 86 infertile men, a 2-month crossover trial of L-carnitine 2 g/day significantly improved sperm concentration and motility versus placebo, with greatest benefit in men with lower baseline motile sperm.
- Effect
- Benefit
- Dose
- 2 g/day
- Population
- Infertility patients
- Participants
- 86
- Ages
- 20–40
RCT[Treatment with carnitine, acetyl carnitine, L-arginine and ginseng improves sperm motility and sexual health in men with asthenopermia]2002n=180
An RCT in 180 men with asthenozoospermia found treatment with carnitine, acetylcarnitine, L-arginine, and ginseng significantly improved progressive sperm motility and sexual satisfaction versus no treatment.
- Effect
- Benefit
- Population
- Men with asthenozoospermia
- Participants
- 180
RCTAntioxidant treatment with carnitines is effective in infertile patients with prostatovesiculoepididymitis and elevated seminal leukocyte concentrations after treatment with nonsteroidal anti-inflammatory compounds2002n=30
An RCT in 98 infertile men with prostatovesiculoepididymitis found carnitines after 2 months of NSAIDs produced the greatest reduction in seminal reactive oxygen species and greatest gains in sperm motility.
- Effect
- Benefit
- Duration
- 4 months
- Population
- Pregnant women
- Participants
- 30
ZincView supplement →
Consider purchase·★★★★★
How we scored this▸
- It is not clear if taking zinc supplements helps men with infertility.
- Some studies show that taking 66 mg of zinc sulfate daily may increase sperm count, testosterone, and chances of pregnancy in men with low testosterone and unexplained infertility.
- Zinc also improved sperm shape by about one-third in men with a severe varicocele.
- However, other research found that a lower dose of 30 mg zinc combined with folic acid daily for 6 months did not improve sperm shape or pregnancy rates.
- Zinc is also included in some combination products with other nutrients that seem to improve sperm count, movement, and concentration, but these results are uncertain because there was no comparison group.
- A small study suggested zinc-containing antioxidant supplements might help IVF success, but it is unclear if zinc or the other antioxidants are responsible.
- More research is needed.
Browse 6 studies
Clinical trialThe Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022n=163
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 450 mg/day
- Population
- Pregnant women
- Participants
- 163
RCTEffect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial2020n=1,185
A randomized trial of 1185 pregnant women found that 5 mg folic acid + 30 mg zinc/day for 6 months among a general population of couples seeking infertility treatment, the use of folic acid and zinc supplementation by male partners, compared with placebo, did not significantly improve semen quality or couples' live birth rates.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 5 mg folic acid + 30 mg zinc/day
- Population
- Pregnant women
- Participants
- 1,185
- Ages
- 18–45
RCTEffects of supplement therapy on sperm parameters, protamine content and acrosomal integrity of varicocelectomized subjects2013
A randomized trial in men found that we may conclude that co-administration of zinc and folic acid significantly improved sperm parameters and increased varicocelectomy outcomes.
- Effect
- Benefit
- Duration
- 6 months
- Population
- Men
RCTA randomised control trial examining the effect of an antioxidant (Menevit) on pregnancy outcome during IVF-ICSI treatment2007n=60
In 60 couples with severe male-factor infertility undergoing IVF-ICSI, 3 months of Menevit antioxidant (including zinc) before treatment raised viable pregnancy rate to 38.5% versus 16% on placebo.
- Effect
- Benefit
- Duration
- 3 months
- Population
- Pregnant women
- Participants
- 60
RCTEffects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial2002n=211
A randomized trial in subfertile men found that 5 mg/day for 26 weeks pre-intervention concentrations of folate and zinc in blood and seminal plasma did not significantly differ between fertile and subfertile men.
- Effect
- No Benefit
- Duration
- 26 weeks
- Dose
- 5 mg/day
- Population
- Subfertile men
- Participants
- 211
Clinical trialEffect of zinc administration on plasma testosterone, dihydrotestosterone, and sperm count1981n=37
In 37 infertile men, oral zinc raised testosterone and sperm count in 22 men with baseline testosterone below 4.8 ng/mL, with nine pregnancies in that subgroup, but had no effect in 15 men with normal testosterone.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 37
Alpha-Lipoic AcidView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Taking alpha-lipoic acid might help improve some sperm qualities in men with infertility, but it’s unclear if it improves chances of pregnancy or live birth.
- Studies show that taking 600 mg daily for 80–90 days slightly improves sperm movement and shape but does not affect sperm count or pregnancy rates.
- In men with damaged sperm DNA, alpha-lipoic acid did not improve sperm health or pregnancies.
- A combination supplement including alpha-lipoic acid used before fertility treatments increased pregnancy rates and lowered miscarriage rates, but it’s unclear if this was due to alpha-lipoic acid or other ingredients.
Browse 3 studies·1 meta-analysis
MetaEfficacy of Alpha Lipoic Acid Supplementation in Sperm Parameters: A Systematic Review and Meta-Analysis of Randomized Trials2025n=250
A meta-analysis of 5 RCTs (250 infertile men) found alpha-lipoic acid improved sperm motility and reduced abnormal morphology over ~3 months but did not significantly change sperm concentration or pooled pregnancy rates.
- Effect
- Benefit
- Population
- Pregnant women
- Participants
- 250
- Avg age
- ~28
RCTAlpha-Lipoic Acid Ameliorates Sperm DNA Damage and Chromatin Integrity in Men with High DNA Damage: A Triple Blind Randomized Clinical Trial2022
In 63 infertile men with high sperm DNA fragmentation, 80 days of oral alpha-lipoic acid 600 mg/day significantly reduced DNA damage and chromatin defects and lowered seminal lipid peroxidation versus placebo.
- Effect
- Benefit
- Dose
- 600 mg/day
- Population
- Men with infertility
ObservationalControlled, prospective, observational study on the efficiency and tolerability of a combination of potential Nrf2-inducing antioxidants and micronutrients as pre-treatment for ICSI in dyspermic patients with previous failure2017
In 59 dyspermic men pretreated 4 weeks with alpha-lipoic acid plus glutathione before ICSI, fertilization rate, embryo quality, implantation rate, and clinical pregnancy rose significantly versus prior IVF attempts.
- Effect
- Benefit
- Duration
- 4 weeks
- Population
- Pregnant women
- Avg age
- ~40
LycopeneView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- In men with unknown causes of infertility, taking lycopene twice daily for 3 months improved sperm count, movement, and shape compared to before treatment.
- However, the study did not include a comparison group, so more research is needed to be sure of these benefits.
Browse 2 studies·1 meta-analysis
MetaEffectiveness of non-pharmaceutical intervention on sperm quality: a systematic review and network meta-analysis2023
A network meta-analysis of RCTs on non-pharmaceutical male infertility interventions found lycopene significantly improved sperm concentration (MD 8.79) and total motility (MD 19.91) vs placebo.
- Effect
- Benefit
- Population
- Infertility patients
Clinical trialLycopene therapy in idiopathic male infertility – a preliminary report2002n=20
A 3-month pilot study of 30 men with idiopathic infertility given 2,000 mcg lycopene twice daily found 66% improved sperm concentration, 53% improved motility, and 23% achieved pregnancy.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 2000 mcg/day
- Population
- Infertility patients
- Participants
- 20
AshwagandhaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if ashwagandha helps male infertility.
- Early studies found that taking ashwagandha root powder or extract for about 3 months modestly improved hormone levels and sperm quality compared to before treatment.
- These studies did not compare the results to a placebo or other treatment.
Browse 2 studies
RCTClinical Evaluation of the Spermatogenic Activity of the Root Extract of Ashwagandha (Withania somnifera) in Oligospermic Males: A Pilot Study2013n=25
In 46 oligospermic men over 90 days, ashwagandha root extract 675 mg/day increased sperm count 167%, motility 57%, and semen volume 53% versus placebo.
- Effect
- Benefit
- Duration
- 90 days
- Dose
- 675 mg/day
- Population
- Older men
- Participants
- 25
- Ages
- 22–40
Controlled trialWithania somnifera improves semen quality by regulating reproductive hormone levels and oxidative stress in seminal plasma of infertile males2010n=75
In 75 infertile men, ashwagandha normalized stress-related oxidative markers and reversed low testosterone, LH, FSH, and prolactin versus infertile baseline.
- Effect
- Benefit
- Population
- Men with infertility
- Participants
- 75
AstaxanthinView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is uncertain if astaxanthin helps male infertility.
- One small, low-quality study found that taking astaxanthin daily for 3 months did not improve sperm quality but might increase pregnancy rates in couples undergoing insemination.
- Another study found no benefit to sperm count or movement.
Browse 2 studies
RCTEffect of the oral intake of astaxanthin on semen parameters in patients with oligo-astheno-teratozoospermia: a randomized double-blind placebo-controlled trial2020n=72
In 72 oligo-astheno-teratozoospermic men over 3 months, astaxanthin 16 mg/day did not improve semen parameters versus placebo, while placebo group sperm concentration rose significantly.
- Effect
- No Benefit
- Duration
- 3 months
- Dose
- 16 mg/day
- Population
- Men with infertility
- Participants
- 72
RCTCombined conventional/antioxidant "Astaxanthin" treatment for male infertility: a double blind, randomized trial2005n=19
In 30 infertile men on conventional therapy, adding astaxanthin 16 mg/day for 3 months improved sperm motility and pregnancy rate (54% vs 10%) versus conventional therapy alone.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 16 mg/day
- Population
- Pregnant women
- Participants
- 19
MultivitaminView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- There is not enough evidence to determine if multivitamin supplementation has any benefit for male infertility.
Browse 2 studies
RCTComparison of the effects of coenzyme Q10 and Centrum multivitamins on semen parameters, oxidative stress markers, and sperm DNA fragmentation in infertile men with idiopathic oligoasthenospermia2022n=130
A 3-month RCT of 130 infertile men found Centrum multivitamins improved some semen parameters similarly to coenzyme Q10.
- Effect
- Benefit
- Duration
- 3 months
- Dose
- 200 mg/day
- Population
- Infertile men
- Participants
- 130
Resveratrol-Based Multivitamin Supplement Increases Sperm Concentration and Motility in Idiopathic Male Infertility: A Pilot Clinical Study2020n=20
A 6-month study of 20 men found a resveratrol-based multivitamin increased sperm concentration and motility versus baseline.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 150 mg/day
- Population
- Men
- Participants
- 20
- Ages
- 18–50
Panax GinsengView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is not clear if taking Panax ginseng helps with male infertility.
- In men with chronic prostatitis caused by Chlamydia infection, a combination supplement containing Panax ginseng, amino acids, and an antibiotic taken daily for 6 months improved sperm count and movement better than the antibiotic alone.
- It is unclear which ingredient is responsible for this effect.
Browse 1 study
RCTSemen quality in patients with Chlamydia trachomatis genital infection treated concurrently with prulifloxacin and a phytotherapeutic agent2012n=206
In 206 men with Chlamydia-associated oligoasthenoteratozoospermia, 6 months of FERTIMEV (L-arginine, L-carnitine, acetyl-L-carnitine, ginseng) plus prulifloxacin improved sperm concentration and motility more than antibiotic alone.
- Effect
- Benefit
- Duration
- 14 days
- Dose
- 600 mg
- Population
- Men with chronic prostatitis
- Participants
- 206
SeleniumView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- It is unclear if taking selenium supplements alone or with other antioxidant vitamins and nutrients helps men with unexplained infertility have more pregnancies or live births.
- Some studies suggest selenium can modestly improve sperm numbers and movement but does not improve sperm shape.
- One study found that a supplement with selenium and other ingredients improved various sperm measures over 6 months, but effects on pregnancy are unknown and the specific role of selenium is uncertain.
- More research is needed to confirm selenium’s benefits for male fertility.
Browse 7 studies·3 meta-analyses
MetaThe Effect of Dietary Supplements on Male Infertility in Terms of Pregnancy, Live Birth, and Sperm Parameters: A Systematic Review and Meta-Analysis2025
A 2024 meta-analysis of 50 male infertility RCTs found selenium and other supplements improved individual sperm parameters but did not increase pregnancy or live birth rates.
- Effect
- No Benefit
- Population
- Pregnant women
MetaSystematic Review and Meta-analysis on Effect of Carnitine, Coenzyme Q10 and Selenium on Pregnancy and Semen Parameters in Couples With Idiopathic Male Infertility2022
A meta-analysis of 20 male infertility RCTs found selenium, carnitine, or coenzyme Q10 improved sperm motility and concentration but not pregnancy rates versus placebo.
- Effect
- No Benefit
- Population
- Pregnant women
MetaThe Effect of Antioxidants on Sperm Quality Parameters and Pregnancy Rates for Idiopathic Male Infertility: A Network Meta-Analysis of Randomized Controlled Trials2022n=1,917
A network meta-analysis of 23 RCTs (1917 patients) found L-carnitine ranked first for sperm motility and morphology and ω-3 fatty acids for concentration, but no antioxidant significantly improved pregnancy rate versus placebo.
- Effect
- No Benefit
- Population
- Pregnant women
- Participants
- 1,917
Clinical trialThe Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022n=163
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 450 mg/day
- Population
- Pregnant women
- Participants
- 163
RCTThe role of Vitamin E - Selenium - Folic Acid Supplementation in Improving Sperm Parameters After Varicocelectomy: A Randomized Clinical Trial2019n=60
In 60 varicocelectomy patients over 6 months, vitamin E-selenium-folic acid supplementation improved sperm count and motility versus control after surgery.
- Effect
- Benefit
- Duration
- 6 months
- Population
- Subfertile men
- Participants
- 60
RCTThe effect of oral selenium supplementation on human sperm motility1998n=69
In 69 subfertile men over 3 months, oral selenium raised plasma selenium but did not significantly improve sperm motility versus placebo.
- Effect
- Benefit
- Duration
- 3 months
- Population
- Subfertile men
- Participants
- 69
Controlled trialSelenium supplementation enhances the element concentration in blood and seminal fluid but does not change the spermatozoal quality characteristics in subfertile men1995n=17
In 33 subfertile men over 12 weeks, selenium 200 mcg/day raised blood and seminal selenium and GSH-Px but did not improve sperm quality characteristics.
- Effect
- No Benefit
- Duration
- 12 weeks
- Dose
- 200 mcg/day
- Population
- Subfertile men
- Participants
- 17
Vitamin B9 (Folate)View supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Some small studies suggest that folic acid, either on its own or together with zinc, can increase sperm count in men with unexplained infertility or with a serious type of varicocele.
- But another small study found that taking folic acid along with selenium and vitamin E for 3 months did not improve sperm health compared to a placebo, and it did not help with pregnancy outcomes.
- A larger, well‑designed study also showed that taking folic acid with zinc for 6 months did not improve sperm shape, pregnancy chances, or live birth rates.
- Folic acid has also been studied in combination with other supplements.
- One study of a product containing several vitamins and nutrients, including folic acid, vitamin C, zinc, carnitine, coenzyme Q10, selenium, and vitamin B12 (Proxeed Plus), suggested possible benefits for sperm count, concentration, and motility after 6 months of use, especially in men with more severe varicocele.
- However, this study did not compare results against a placebo, which limits how reliable the findings are.
Browse 5 studies
Clinical trialThe Role and Place of Antioxidants in the Treatment of Male Infertility Caused by Varicocele2022n=163
In 163 men with idiopathic or varicocele-related infertility, 6 months of an antioxidant formula containing 3,450 mg/day L-carnitine plus acetyl-L-carnitine improved sperm count, concentration, and motility, with greatest benefit in grade III varicocele.
- Effect
- Benefit
- Duration
- 6 months
- Dose
- 450 mg/day
- Population
- Pregnant women
- Participants
- 163
RCTThe 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 Trial2021n=35
A randomized trial of 35 men found that 200 μg/day according to between-group analysis, no significant difference was found in mean semen volume (P=0.610), sperm concentration (P=0.126), total sperm motility (P=0.765), progressive sperm motility (P=0.767), normal sperm morph (P=0.403), SMI (P=0.556) or FSC (P=0.706) between.
- Effect
- No Benefit
- Dose
- 200 μg/day
- Population
- Men
- Participants
- 35
RCTEffect of Folic Acid and Zinc Supplementation in Men on Semen Quality and Live Birth Among Couples Undergoing Infertility Treatment: A Randomized Clinical Trial2020n=1,185
A randomized trial of 1185 pregnant women found that 5 mg folic acid + 30 mg zinc/day for 6 months among a general population of couples seeking infertility treatment, the use of folic acid and zinc supplementation by male partners, compared with placebo, did not significantly improve semen quality or couples' live birth rates.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 5 mg folic acid + 30 mg zinc/day
- Population
- Pregnant women
- Participants
- 1,185
- Ages
- 18–45
RCTEffects of supplement therapy on sperm parameters, protamine content and acrosomal integrity of varicocelectomized subjects2013
A randomized trial in men found that we may conclude that co-administration of zinc and folic acid significantly improved sperm parameters and increased varicocelectomy outcomes.
- Effect
- Benefit
- Duration
- 6 months
- Population
- Men
RCTEffects of folic acid and zinc sulfate on male factor subfertility: a double-blind, randomized, placebo-controlled trial2002n=211
A randomized trial in subfertile men found that 5 mg/day for 26 weeks pre-intervention concentrations of folate and zinc in blood and seminal plasma did not significantly differ between fertile and subfertile men.
- Effect
- No Benefit
- Duration
- 26 weeks
- Dose
- 5 mg/day
- Population
- Subfertile men
- Participants
- 211
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| L-Carnitine | ★★★★★68% | 26 | 7 | 37% |
| Acetyl-L-Carnitine | ★★★★★68% | 15 | 5 | 21% |
| Selenium | ★★★★★40% | 7 | 3 | 10% |
| Zinc | ★★★★★68% | 6 | 0 | 8% |
| Vitamin B9 (Folate) | ★★★★★40% | 5 | 0 | 7% |
| Alpha-Lipoic Acid | ★★★★★52% | 3 | 1 | 4% |
| Ashwagandha | ★★★★★44% | 2 | 0 | 3% |
| Astaxanthin | ★★★★★44% | 2 | 0 | 3% |
| Lycopene | ★★★★★48% | 2 | 1 | 3% |
| Multivitamin | ★★★★★44% | 2 | 0 | 3% |
| Panax Ginseng | ★★★★★44% | 1 | 0 | 1% |