NutriDex

The Supplement Research Compendium
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D-Aspartic Acid

Marketed testosterone booster that fails in trained men.

Mixed evidence ⚡Performance

✚ Updated · How we grade evidence

Evidence tier
Mixed
Research weight
Citations
7 verified / 7
Classification
Performance
❝
What the evidence says. Graded mixed: a single 12-day study in untrained men reported a ~42% testosterone rise, but better-controlled RCTs in resistance-trained men found no change — and 6 g/day actually lowered testosterone. No trial shows added muscle or strength. (Mixed evidence: Conflicting results across studies; benefit uncertain.)

What is D-Aspartic Acid?

D-Aspartic Acid is a performance supplement used for marketed to raise testosterone. NutriDex grades the human evidence as Mixed. D-aspartic acid (DAA) is an amino acid sold as a natural testosterone booster. The hype traces to a 2009 study where 23 untrained men taking ~2.7 g/day for 12 days raised testosterone about 42%. That result has not held up: a 2015 RCT found 3 g/day did nothing and 6 g/day reduced total and free testosterone, and a 2017 RCT in resistance-trained men found no change in testosterone (only a ~16% drop in estradiol) and no extra muscle or strength versus placebo. A 2017 systematic review of four human trials called the evidence inconsistent and low-quality. Separate work links low seminal D-aspartate to poor sperm quality, and a small 2025 RCT combining DAA with ubiquinol and zinc improved sperm motility — but DAA's solo fertility benefit is unproven. For its main marketed claim, boosting testosterone and gains, the human data are mixed to negative.

Purported Benefits

✓Marketed to raise testosterone
✓Marketed muscle & strength support
✓Possible male fertility support

Evidence by outcome

The same supplement can be well-proven for one use and unproven for another — here is the human evidence graded outcome by outcome.

OutcomeEvidenceEffectStudies
Raise testosteroneInitial 42% spike not replicated; later RCTs show no rise and 6 g/day can lower testosterone; review rates evidence inconsistent. Moderate — no effect · negligible 4
Muscle & strength gains12-week RCT in trained men with 6 g/day plus training showed no extra strength or muscle vs placebo. Moderate — no effect · negligible 1
Male fertility / sperm qualityLow seminal D-aspartate links to poor sperm; one small RCT improved motility but only as a combination with ubiquinol+zinc, so solo effect is unproven. Preliminary ↔ mixed 2

Dosing & Compounds

Typical Dose
Common label dose is 3 g/day; testosterone-boosting trials used 2–6 g/day for 12 days to 12 weeks, with no consistent benefit.
Active Compounds
D-aspartic acid (D-aspartate)Sodium D-aspartate

Safety & Cautions

DAA is generally well tolerated at 3 g/day, with occasional headache, irritability, nervousness or mild GI upset reported. Higher doses (6 g/day) lowered testosterone in trials, so 'more' is counterproductive. Because it acts on the hypothalamic-pituitary-gonadal axis, avoid it if you take hormonal therapies (testosterone, aromatase inhibitors, fertility drugs) without medical advice, and it is not appropriate in pregnancy, breastfeeding, or for adolescents. Formal drug-interaction data are lacking. Educational only — always check with your doctor or pharmacist before combining D-Aspartic Acid with any medicine.

Key Studies

Systematic review Roshanzamir 2017 ✓ PubMed
Systematic review of 4 human and 23 animal studies: human results inconsistent and low-quality; no firm testosterone benefit established.
RCT GamalEl Din 2025 ✓ PubMed
RCT (n=75): DAA 2660 mg + ubiquinol + zinc improved progressive sperm motility and total testosterone vs placebo over 3 months.
RCT Ploszczyca et al. 2023 ✓ PubMed
In a randomized controlled trial of 16 male boxers, 6 g/day D-aspartic acid for 14 days during altitude (normobaric hypoxia) training had no significant effect on resting testosterone, the testosterone/cortisol ratio, LH, or hematological responses versus control.
RCT Melville 2015 ✓ PubMed
In resistance-trained men, 3 g/day DAA had no hormonal effect; 6 g/day significantly reduced total (~13%) and free testosterone.
RCT Melville 2017 ✓ PubMed
6 g/day DAA over 12 weeks with training gave no change in total/free testosterone and no extra strength or muscle; estradiol fell ~16%.
RCT Topo 2009 ✓ PubMed
23 untrained men given ~2.7 g/day sodium D-aspartate for 12 days raised serum testosterone ~42% (4.5 to 6.4 ng/mL) and LH ~33%.
Cohort D'Aniello 2005 ✓ PubMed
Seminal D-aspartate was far lower in subfertile (oligoasthenoteratospermic) men (26 vs 80 nmol/mL), suggesting a role in sperm quality.
7 sources cited · 7 verified Search all studies on PubMed ↗

Common questions about D-Aspartic Acid

What is D-Aspartic Acid used for?

D-Aspartic Acid is most often taken for Marketed to raise testosterone, Marketed muscle & strength support, Possible male fertility support. Marketed testosterone booster that fails in trained men.

Does D-Aspartic Acid work — what does the evidence say?

Mixed evidence. Conflicting results across studies; benefit uncertain. D-aspartic acid (DAA) is an amino acid sold as a natural testosterone booster. The hype traces to a 2009 study where 23 untrained men taking ~2.7 g/day for 12 days raised testosterone about 42%. That result has not held up: a 2015 RCT found 3 g/day did nothing and 6 g/day reduced total and free testosterone, and a 2017 RCT in resistance-trained men found no change in testosterone (only a ~16% drop in estradiol) and no extra muscle or strength versus placebo. A 2017 systematic review of four human trials called the evidence inconsistent and low-quality. Separate work links low seminal D-aspartate to poor sperm quality, and a small 2025 RCT combining DAA with ubiquinol and zinc improved sperm motility — but DAA's solo fertility benefit is unproven. For its main marketed claim, boosting testosterone and gains, the human data are mixed to negative.

What is the typical dose of D-Aspartic Acid?

Common label dose is 3 g/day; testosterone-boosting trials used 2–6 g/day for 12 days to 12 weeks, with no consistent benefit.

Is D-Aspartic Acid safe? Any cautions or side effects?

DAA is generally well tolerated at 3 g/day, with occasional headache, irritability, nervousness or mild GI upset reported. Higher doses (6 g/day) lowered testosterone in trials, so 'more' is counterproductive. Because it acts on the hypothalamic-pituitary-gonadal axis, avoid it if you take hormonal therapies (testosterone, aromatase inhibitors, fertility drugs) without medical advice, and it is not appropriate in pregnancy, breastfeeding, or for adolescents. Formal drug-interaction data are lacking.

How many studies support D-Aspartic Acid?

NutriDex cites 7 sources for D-Aspartic Acid, graded "Mixed".

Cite this page
APA

Peh, D. (2026). D-Aspartic Acid: Benefits, Dosage, Side Effects & Evidence. NutriDex — The Supplement Research Compendium. Retrieved 26 Jun 2026, from https://nutridex.info/s/d-aspartic-acid

BibTeX
@misc{nutridex_d_aspartic_acid,
  author       = {Peh, Daryl},
  title        = {D-Aspartic Acid: Benefits, Dosage, Side Effects \& Evidence},
  year         = {2026},
  howpublished = {NutriDex --- The Supplement Research Compendium},
  url          = {https://nutridex.info/s/d-aspartic-acid},
  note         = {Reviewed by Dr Daryl Peh, MBBS Singapore, MMed FM. Accessed 2026-06-26}
}

For medical claims, citing the underlying primary studies linked above is preferred. NutriDex is an educational reference, not medical advice.

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