Are Supplements Risky for Male Fertility?
Taking supplements for male fertility is generally not risky and may offer modest benefits, but the evidence supporting their effectiveness remains conflicting and of low quality, meaning you should counsel patients that benefits are uncertain rather than guaranteed. 1
Understanding the Evidence Quality
The current state of supplement research for male fertility is problematic:
The evidence base is fundamentally weak. A Cochrane systematic review of 61 studies involving 6,264 infertile men showed that antioxidant therapy may improve live birth rates, but when studies with high risk of bias were removed, this benefit disappeared entirely. 1
Methodological problems plague the field. Most studies suffer from poor design, lack of standardization in measuring oxidative stress and sperm parameters, and significant heterogeneity that makes meta-analysis challenging. 2
Only a tiny fraction of studies measure what matters. Out of 48 trials reviewed, only 7 reported clinical pregnancy rates and only 4 reported live births—the outcomes that actually matter to patients. 2
Safety Profile: Generally Low Risk
The good news is that supplements appear to have a safe tolerability profile with minimal reported adverse effects. 1
Aromatase inhibitors (anastrozole, letrozole) used off-label for male infertility show safe tolerability profiles, though these are prescription medications rather than OTC supplements. 1
The primary risk is not toxicity but rather opportunity cost—patients may delay proven treatments while pursuing supplements with questionable efficacy. 3
What the Guidelines Actually Recommend
Major professional societies are cautious about recommending supplements:
The European Association of Urology (2025) states that evidence for antioxidant therapy in male infertility remains conflicting and cannot draw conclusive recommendations. 1
The American Urological Association/American Society for Reproductive Medicine (2021) advises clinicians to inform patients that supplement benefits have questionable clinical usefulness for treating male infertility. 2
Human Reproduction Update (2017) concluded that available data are insufficient to recommend antioxidant therapy for men with abnormal semen parameters. 2
Specific Supplements with Some Supporting Evidence
If patients insist on trying supplements, these have at least some RCT support:
Prebiotic/probiotic compounds: One RCT of 56 men showed significant improvements in sperm concentration, motility, morphology, and DNA integrity, though larger trials are needed. 1
Specific antioxidants with small RCT support: Coenzyme Q10, L-carnitine, selenium, zinc combined with folate, and glutathione have shown positive effects in small trials. 4
Omega-3 fatty acids from fish and nuts may be beneficial based on dietary pattern studies. 5
What Definitely Helps: Lifestyle Modifications
Rather than focusing on supplements, prioritize proven lifestyle interventions:
Weight loss, physical exercise, and smoking cessation all enhance sperm parameters and should be strongly encouraged. 1
These interventions also reduce cardiovascular risk, which is particularly important since infertile men have higher rates of cardiometabolic disorders and increased cardiovascular mortality compared to fertile men. 1
Critical Substances to Avoid
Some substances pose clear risks to male fertility:
THC/marijuana: The WHO guidelines strongly recommend complete abstinence for men trying to conceive, as evidence demonstrates detrimental effects on sperm quality and fertility potential. 6
CBD: Men with fertility concerns should be cautious about CBD use, particularly at higher doses or extended periods, and should disclose use to healthcare providers. 7
Alcohol and tobacco: Moderation of alcohol and smoking cessation are supported by sufficient literature. 4
Practical Clinical Approach
When counseling patients about supplements:
Acknowledge that while biologically plausible, supplements lack robust scientific support due to poorly designed studies. 3
Explain that the absence of evidence of harm doesn't equal evidence of benefit—patients should understand they're taking a gamble with uncertain payoff. 3
Emphasize that no supplement has been proven beyond doubt to increase conception rates, though some may improve sperm parameters. 3
Prioritize lifestyle modifications first (weight loss, exercise, smoking cessation) as these have stronger evidence and broader health benefits. 1
If patients choose supplements, ensure they contain studied doses and avoid excessive amounts beyond established upper limits. 8
Screen all infertile men for modifiable cardiovascular risk factors, as the urological assessment represents an opportunity to target early-stage disease and improve life expectancy. 1