D-Aspartic Acid
Research reviewed: Up until 03/2026
D-Aspartic Acid (D-Aspartic Acid (DAA)) is a dietary supplement with 4 published peer-reviewed studies involving 256 participants, researched for Testosterone Support, Sports Performance.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
Testosterone Support
ModerateSports Performance
WeakResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
Testosterone Support
To compare the efficacy of D-aspartic acid supplementation on testosterone levels with fluoxetine in resistance-trained men
Study Type
Randomized, controlled
Purpose
To compare the efficacy of D-aspartic acid supplementation on testosterone levels with fluoxetine in resistance-trained men
Dose
6 grams DAA/day
Participants
Resistance-trained men
Duration
12 weeks
Results
Total testosterone was significantly reduced in 6g DAA group, and free testosterone was significantly reduced compared to placebo.
How They Measured It
Total testosterone, free testosterone, LH levels
To evaluate D-aspartic acid supplementation effects on testosterone in resistance-trained men over 3 months
Study Type
Randomized, controlled trial
Purpose
To evaluate D-aspartic acid supplementation effects on testosterone in resistance-trained men over 3 months
Dose
D-aspartic acid supplementation
Participants
Resistance-trained men
Duration
3 months
Results
D-aspartic acid supplementation had no significant effect on serum testosterone, free testosterone, or body composition in resistance-trained men.
How They Measured It
Serum testosterone, free testosterone, body composition
Sports Performance
To synthesize effects of D-aspartic acid supplementation on testosterone and training outcomes
Study Type
Systematic review
Purpose
To synthesize effects of D-aspartic acid supplementation on testosterone and training outcomes
Dose
3-6 grams/day
Participants
Meta-analysis of multiple RCTs in trained men
Duration
12 weeks typical
Results
DAA shows increases in testosterone in untrained men but no changes or reductions in resistance-trained men. Evidence shows DAA is ineffective at improving training outcomes.
How They Measured It
Literature synthesis of RCT evidence
To evaluate D-aspartic acid supplementation on testosterone and hormonal responses in resistance-trained men undergoing heavy training
Study Type
Randomized, double-blind, controlled
Purpose
To evaluate D-aspartic acid supplementation on testosterone and hormonal responses in resistance-trained men undergoing heavy training
Dose
D-aspartic acid supplementation
Participants
Resistance-trained men
Duration
28 days
Results
DAA had no significant effect on resting LH or testosterone/cortisol ratio during intensive training.
How They Measured It
Serum testosterone, cortisol, LH, training outcomes
Frequently Asked Questions
Common questions about D-Aspartic Acid research
There are currently 6 peer-reviewed studies on D-Aspartic Acid (D-Aspartic Acid (DAA)), involving 256 total participants. Research covers Testosterone, Male fertility, Athletic performance. The overall evidence strength is rated as Moderate.
The evidence is currently rated as "Moderate Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (4 human studies), and reported outcomes.
D-Aspartic Acid has been researched for: Testosterone, Male fertility, Athletic performance. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 4 out of 6 studies are human trials. Human trials carry more weight in our evidence scoring system.
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