Which supplements, among zinc, DHEA (Dehydroepiandrosterone), quercetin, resveratrol, pycnogenol, and saw palmetto, can increase testosterone levels in men?

Effectiveness of Supplements for Increasing Testosterone in Men

Based on the available evidence, DHEA is the only supplement among zinc, DHEA, quercetin, resveratrol, pycnogenol, and saw palmetto that has demonstrated significant ability to increase testosterone levels in men through randomized controlled trials. 1

Evidence for Each Supplement

DHEA (Dehydroepiandrosterone)

• DHEA supplementation significantly increases testosterone levels in men (weighted mean difference: 21.36 ng/dl) based on a comprehensive meta-analysis of 42 publications 1
• Higher doses of DHEA (>50 mg/day) produce greater testosterone increases (WMD: 57.96 ng/dl) compared to lower doses (≤50 mg/day) (WMD: 19.43 ng/dl) 1
• Shorter intervention duration (≤12 weeks) shows greater testosterone increases (WMD: 44.64 ng/dl) compared to longer interventions (>12 weeks) (WMD: 19 ng/dl) 1
• The effect is more pronounced in younger men (<60 years) than older men (>60 years) 1

Zinc

• While zinc deficiency reduces testosterone levels, the evidence for zinc supplementation increasing testosterone in men with normal baseline zinc levels is limited 2
• Zinc supplementation may improve testosterone levels primarily in zinc-deficient individuals, but the effect varies depending on baseline zinc and testosterone levels 2
• The correlation between serum zinc and total testosterone is positive, suggesting a relationship, but this doesn't necessarily translate to significant increases with supplementation in men with normal zinc levels 2

Other Supplements (Quercetin, Resveratrol, Pycnogenol, Saw Palmetto)

• No strong evidence from randomized controlled trials supports the use of quercetin, resveratrol, pycnogenol, or saw palmetto for increasing testosterone levels 3
• In a systematic review of popular male testosterone supplements, 68% of ingredients received C or D grades for contradicting, negative, or lacking evidence 3
• Many marketed testosterone-boosting supplements lack published randomized controlled trials supporting their efficacy 3

Clinical Implications

When to Consider Testosterone Therapy

• Rather than supplements, clinicians should consider proper testosterone replacement therapy for men with documented testosterone deficiency (levels below 300 ng/dL) 4, 5
• Testosterone therapy has demonstrated small but clinically meaningful improvements in sexual function, erectile function, and quality of life in men with low testosterone levels 6
• Proper diagnosis requires two separate morning measurements of total testosterone below 300 ng/dL 5

Monitoring and Safety

• For men on testosterone therapy, target trough testosterone levels should be maintained within 300-1,000 ng/dL 5
• Regular monitoring of hematocrit/hemoglobin is essential as testosterone therapy commonly causes erythrocytosis 4
• Prostate monitoring through digital rectal examination and PSA measurement is recommended before and during treatment 4

Important Considerations and Pitfalls

• Many men receive testosterone therapy without proper diagnosis - studies estimate that up to 25% of men who receive testosterone therapy do not meet diagnostic criteria for testosterone deficiency 5
• Nearly half of men placed on testosterone therapy do not have their testosterone levels checked after therapy commences 5
• Contrary to marketing claims, most prohormone nutritional supplements do not produce anabolic or ergogenic effects in men and may pose health risks 7
• Lifestyle modifications such as weight loss and increased physical activity can naturally increase total testosterone levels 4
• Exogenous testosterone therapy should not be prescribed to men who are currently trying to conceive as it can interrupt normal spermatogenesis 4

In conclusion, while DHEA shows promise for increasing testosterone levels, the evidence for other supplements is limited or nonexistent. For men with clinically low testosterone, properly monitored testosterone replacement therapy remains the most evidence-based approach.