What supplements can men take to enhance fertility?

Supplements for Male Fertility Enhancement

Men seeking to enhance fertility should be counseled that supplements such as antioxidants and vitamins have questionable clinical utility for improving fertility outcomes, with inadequate data to recommend specific agents. 1

Evidence-Based Recommendation

The 2021 AUA/ASRM guidelines explicitly state that clinicians should counsel patients that the benefits of supplements (e.g., antioxidants, vitamins) are of questionable clinical utility in treating male infertility, with existing data inadequate to provide recommendation for specific agents. 1 This represents a Grade B level of evidence with a conditional recommendation. 1

The guideline further clarifies: "There are no clear, reliable data to support use of the variety of supplements (vitamins, antioxidants, nutritional supplement formulations) that have been offered to men attempting conception. Current data suggest that they are likely not harmful, but they are of questionable value in improving fertility outcomes." 1

Carnitine Supplementation: Limited Evidence

While not recommended in major guidelines, research on L-carnitine shows:

• Sperm parameter improvements: L-carnitine supplementation at 2 g/day may improve sperm concentration, motility, and morphology in men with idiopathic infertility. 2, 3

• No proven pregnancy benefit: Despite improvements in semen parameters, there is no demonstrable effect on clinical pregnancy rates or live birth rates. 4

• Mechanism: L-carnitine acts as an antioxidant, reducing reactive oxygen species (ROS) and providing energy for sperm metabolism. 5

• Treatment duration: Studies showing benefit typically required 3-6 months of supplementation. 6

Antioxidant Therapy: Conflicting Evidence

The 2025 European Association of Urology guidelines note that evidence for antioxidant therapy remains conflicting:

• A Cochrane review showed antioxidants may improve live birth rates, but when studies with high risk of bias were removed, this benefit disappeared. 1

• The 2017 WHO evidence review concluded that methodological quality of most antioxidant studies is poor, with only 7 of 48 trials reporting clinical pregnancy rates and only 4 reporting live births. 1

• No specific antioxidant can be recommended based on current evidence. 1

What Actually Works: Evidence-Based Alternatives

Instead of supplements, prioritize interventions with proven efficacy:

For Specific Hormonal Conditions:

• Hypogonadotropic hypogonadism (HH): Gonadotropin therapy (hCG with or without FSH) is highly effective, with 75% achieving sperm production in the ejaculate. 1

• Low testosterone with normal pituitary function: Aromatase inhibitors, hCG, or SERMs may be used, though benefits are limited. 1

For Idiopathic Infertility:

• Assisted reproductive technology (ART) including IVF/ICSI offers higher pregnancy rates and faster conception compared to any supplement or medical therapy. 1

• FSH analogues may be considered for idiopathic infertility to improve sperm concentration and pregnancy rates, though benefits are small and cost-effectiveness is questionable. 1

Lifestyle Modifications: Proven Benefit

Lifestyle changes should be the first-line recommendation as they improve both fertility and overall health:

• Weight loss in obese men can improve sperm parameters and testosterone levels. 1

• Smoking cessation may improve semen quality, though evidence quality is low. 1

• Regular physical exercise enhances sperm parameters. 1

• These interventions are particularly important given that infertile men have higher cardiovascular mortality and cardiometabolic disease risk. 1

Critical Warnings

Testosterone therapy is absolutely contraindicated in men seeking fertility, as it suppresses spermatogenesis and can cause azoospermia. 1

Anabolic steroid use must be discontinued, as ongoing use suppresses spermatogenesis and interferes with fertility. 1

Clinical Algorithm

1. Evaluate for treatable causes: Check FSH, testosterone, and prolactin to identify hormonal disorders amenable to specific therapy. 1

2. Address modifiable risk factors: Counsel on weight loss, smoking cessation, exercise, and discontinuation of gonadotoxic substances. 1

3. For specific hormonal deficiencies: Use gonadotropins (HH), or consider SERMs/AIs (low testosterone with normal pituitary). 1

4. For idiopathic infertility: Counsel that ART offers superior outcomes compared to empiric medical therapy or supplements. 1

5. If patient insists on supplements: Inform them of questionable benefit, lack of evidence for specific agents, and that they are likely not harmful but of uncertain value. 1

Common Pitfalls

• Prescribing testosterone to infertile men seeking conception—this will worsen fertility. 1

• Delaying ART while pursuing prolonged empiric supplement trials—couples lose valuable time. 1

• Recommending specific antioxidant formulations without evidence—no particular agent has proven superiority. 1