Supplement
D-aspartic acid
SaveAn amino acid isomer involved in hypothalamic GnRH release, marketed as a testosterone booster. Human evidence is mixed and effect sizes are small.
Quick verdict
Initial studies showed transient testosterone increases, but longer trials and replications are mostly negative. Not a reliable testosterone booster.
Evidence score
A rough internal score reflecting quantity, quality, and consistency of human evidence. Not a clinical recommendation.
What the research shows
Topo et al. 2009 showed ~40% testosterone increase at 3 g/day over 12 days. However, longer studies (28+ days) by Willoughby and others found no sustained increase and one showed a decrease in trained men.
Benefits
- Involved in GnRH and LH release pathways
- Transient testosterone increase in one short study
- Well-tolerated at standard doses
Dosage notes
2–3 g/day was used in studies. Efficacy is not established at any dose.
Side effects
- Headache
- Irritability (rare)
- GI discomfort
Who should be cautious
No serious safety concerns at standard doses but efficacy is dubious. May transiently affect hormone levels.
What this page cannot tell you
The initial positive study was short-duration and unreplicated in longer trials. Trained athletes show no benefit.
Leaderboard scores
- Libido22
- Muscle18
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