Supplements That Increase Testosterone Levels with Human RCT Results
Based on the available evidence, there are no supplements with conclusive human RCT results that reliably increase testosterone levels in healthy men. 1, 2, 3, 4, 5
D-Aspartic Acid (DAA)
- Multiple human RCTs have shown that D-aspartic acid supplementation does not effectively increase testosterone levels in resistance-trained men 2, 3, 4, 5
- One study actually found that 6g/day of D-aspartic acid supplementation for 14 days significantly reduced total and free testosterone levels in resistance-trained men 2
- A 3-month randomized controlled trial showed DAA supplementation (6g/day) was ineffective at changing testosterone levels or positively affecting training outcomes in resistance-trained men 3
- Short-term DAA supplementation (3g/day for 2 weeks) did not influence testosterone or other indicators of the hypothalamic-pituitary-gonadal axis in male climbers 4
- A 28-day study with 3g/day DAA supplementation combined with heavy resistance training showed no effect on serum hormones, body composition, or muscle strength in resistance-trained men 5
Testosterone Replacement Therapy
While not a supplement, it's important to note that medically supervised testosterone replacement therapy is the only reliable method to increase testosterone levels:
- Testosterone therapy has been shown to increase muscle mass, decrease fat mass, and improve muscle strength in men with documented testosterone deficiency 6
- The American Urological Association recommends adjusting testosterone therapy dosing to achieve a total testosterone level in the middle tertile of the normal reference range (450-600 ng/dL) for men with documented testosterone deficiency 6
- Testosterone therapy has demonstrated small improvements in sexual function, erectile function, and quality of life in men with low testosterone levels 6
Important Considerations and Warnings
- Exogenous testosterone therapy should not be prescribed to men who are currently trying to conceive as it can interrupt normal spermatogenesis 6
- Testosterone therapy should not be commenced for a period of three to six months in patients with a history of cardiovascular events 6
- Clinicians should not prescribe alkylated oral testosterone due to potential liver toxicity 6
- Lifestyle modifications such as weight loss, maintaining weight within the recommended range, and increasing physical activity have the potential to increase total testosterone levels and/or reduce symptoms associated with testosterone deficiency 6
Monitoring and Safety
- Regular monitoring of hematocrit/hemoglobin is essential as testosterone therapy commonly causes erythrocytosis, particularly with injectable formulations 7
- Prostate monitoring through digital rectal examination and PSA measurement is recommended before initiating therapy, with regular PSA monitoring during treatment 7
- If hematocrit rises above the reference range, consideration should be given to temporarily withholding therapy, reducing the dose, or performing phlebotomy 7
Conclusion on Supplements
The systematic review of available evidence indicates that despite marketing claims, supplements like D-aspartic acid do not reliably increase testosterone levels in human RCTs 1. The evidence for any supplement association with increased testosterone in men is still sparse, mostly because of limited number and poor quality studies 1.