Reviewed by the Scan Dose Research Team and Clinical Advisory Board
D-Aspartic Acid
LIMITED EVIDENCESupplementLast updated April 2026
SCAN DOSE SUMMARY
D-Aspartic acid was briefly hyped as a natural testosterone booster — our research shows the initial positive study has NOT been replicated in young, healthy men. One trial showed 15% testosterone increase over 12 days in untrained men, but subsequent trials in resistance-trained men found no effect or even slight decreases. The evidence does not support DAA for testosterone boosting in athletic populations.
EVIDENCE GRADES
Testosterone increase (untrained/older men)One positive trial, not replicated (PMID: 19860889)
C
Testosterone (resistance-trained men)Null or negative results (PMID: 24074027)
D
Male fertility (sperm quality)More promising — improved sperm parameters