Not worth it for testosterone and strength.
The label shows how strong the evidence is, not how big the effect is. Tap a claim to see its papers.
One 12-day trial in 23 untrained men reported a 42% testosterone rise; it has never been independently replicated, and a systematic review called the human evidence inconsistent and sparse.[1][2][3]
A single small, short trial of a commercial product (with added B vitamins), with no replication, is weak evidence; a systematic review of 4 human studies found inconsistent results. Grade C.
Each plate is one paper. Taller = stronger study design, wider = more studies pooled. Tap one.
Most marketed testosterone boosters failed to increase total testosterone; D-aspartic acid (2 studies reviewed) was not among the exceptions.
D-aspartic acid raised testosterone in male animal studies, but the four human studies gave inconsistent results and were few and of poor quality.
In 23 men taking sodium D-aspartate for 12 days (20 on placebo), LH and testosterone rose; rat studies showed D-aspartate acts in the pituitary and testes.
No: 3 g/day for 2-4 weeks and 6 g/day for 2-12 weeks did not raise testosterone in trained men, and 6 g/day for 14 days lowered total and free testosterone.[4][5][6][7][8]
Five controlled trials (four placebo-controlled) in resistance-trained men, climbers and boxers found no rise in total or free testosterone or LH. Good null trials in the target population is Grade D.
Each plate is one paper. Taller = stronger study design, wider = more studies pooled. Tap one.
In male boxers at a simulated-altitude camp, 6 g/day for 14 days did not affect testosterone, LH, cortisol ratio or blood responses.
In male climbers, 3 g/day for 2 weeks did not affect testosterone, free testosterone, LH, physical function or blood markers.
In resistance-trained men, 6 g/day for 12 weeks of training did not change total or free testosterone, lowered estradiol, and gave no extra strength or hypertrophy versus placebo.
In resistance-trained men, 6 g/day for 14 days lowered total and free testosterone; 3 g/day had no effect.
In resistance-trained men, 3 g/day for 28 days of heavy training did not change testosterone, LH or estradiol, and strength and body composition rose equally with placebo.
No added benefit: strength and muscle size rose equally with D-aspartic acid and placebo over 28 days (3 g/day) and 12 weeks (6 g/day) of training.[5][6]
Two placebo-controlled training trials in resistance-trained men found no extra strength, hypertrophy or body-composition change. Good null trials is Grade D.
Each plate is one paper. Taller = stronger study design, wider = more studies pooled. Tap one.
In resistance-trained men, 6 g/day for 12 weeks of training did not change total or free testosterone, lowered estradiol, and gave no extra strength or hypertrophy versus placebo.
In resistance-trained men, 3 g/day for 28 days of heavy training did not change testosterone, LH or estradiol, and strength and body composition rose equally with placebo.
D-aspartic acid is the mirror-image form of the amino acid aspartic acid. The body makes it from L-aspartate in the pituitary gland and testes, where it concentrates. The sources do not quantify how much a normal diet provides.
In rats, D-aspartate acts in the pituitary to increase LH release and in testicular Leydig cells to increase testosterone synthesis. The idea is that extra D-aspartic acid would raise LH and then testosterone in people. In trained men this has not happened: LH and testosterone were unchanged, and 6 g/day lowered testosterone.[1][4][6]
Reviewed 03 Oct 2026 · every PubMed ID checked against PubMed
3 g/day in most trials; 6 g/day also tested
The only product with a positive human testosterone result, in one 12-day trial.[1]
If 3 g doesn't work, take 6 g.
6 g/day lowered total and free testosterone in trained men over 14 days.[4]
It is not a prohibited substance, but booster blends that contain it are a high-risk category for contamination.[9]
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