tuneTypical Dose
2-3 g/day
Supplement
D-Aspartic Acid
D-aspartic acid
Evidence TierCWADA NOT PROHIBITED
watchEffect Window
2-3 weeks (non-durable in many studies)
check_circleCompliance
WADA NOT PROHIBITED
Overview
Clinical Summary
D-aspartic acid can transiently shift testosterone-related hormones in short early studies, but modern trials in resistance-trained men do not show reliable performance or body-composition benefits.
Evidence is context dependent. Trials most often evaluate exercise outcomes such as fatigue, blood flow, or muscle soreness, and some show small benefits at adequate doses. Minority uses include support for wound healing, immune function, and sleep quality. Effects vary with baseline protein intake, training status, and coingested nutrients.
Short-term endocrine effects were reported in an early 12-day trial, but later trials in trained men do not show durable testosterone or performance benefits.
Outcomes
What This Is Expected To Influence
Primary Outcomes
- Short-term endocrine marker shifts (mostly exploratory)
- No verified cognitive outcome signal
Secondary Outcomes
- Libido or fatigue-perception effects in mixed small studies
- Hormonal side effects at higher doses
Safety
Contraindications and Interactions
Contraindications
- Pregnancy
- Lactation
- Active endocrine malignancy history
- Uncontrolled hyperandrogenic conditions
Side effects
- Headache
- Sleep disruption
- GI upset
- Irritability or nervousness
- Fatigue
Interactions
- Exogenous testosterone or other hormonal therapies
- Stimulants affecting mood/sleep
- Anti-seizure medications with glutamatergic mechanisms (theoretical)
Avoid if
- Pregnancy or lactation
- Active reproductive planning without clinician review
- Unstable mood disorders
- Persistent poor sleep
- Significant hormone-sensitive medical history
Evidence
Study-level References
d-aspartic-acid-SRC-001Placebo-controlled human trial with parallel animal experiments
Sourceopen_in_newTopo E, Soricelli A, D'Aniello A, et al. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reprod Biol Endocrinol. 2009;7:120. PMID:19860889.
Population: Forty-three adult men in the human arm.
Dose protocol: Daily oral sodium D-aspartate for 12 days
Key findings: Increased LH and testosterone over 12 days in the original positive human trial.
Notes: Foundational positive study, but very short and not decisive for long-term use.
Paper content
This early study created most of the commercial interest in D-aspartic acid because it reported short-term increases in LH and testosterone in men over 12 days. The trial was short and the signal has not translated into reliable benefits in trained or longer-term populations.
d-aspartic-acid-SRC-002Randomized placebo-controlled training study
Sourceopen_in_newWilloughby DS, Spillane M, Schwarz N. Heavy Resistance Training and Supplementation With the Alleged Testosterone Booster Nmda has No Effect on Body Composition, Muscle Performance, and Serum Hormones Associated With the Hypothalamo-Pituitary-Gonadal Axis in Resistance-Trained Males. J Sports Sci Med. 2014;13(1):57-66. PMID:24570624.
Population: Twenty resistance-trained males.
Dose protocol: 1.78 g/day during 28 days of heavy resistance training
Key findings: No improvement in hormonal, body-composition, or performance outcomes versus placebo.
Notes: Directly tests the marketed use case in trained men and comes back negative.
Paper content
In resistance-trained men, D-aspartic-acid-based supplementation did not improve testosterone, strength, or body-composition outcomes during a month of heavy training. This is a key human trial showing that the early positive endocrine signal does not generalize well to the population most likely to buy the supplement.
d-aspartic-acid-SRC-003Randomized double-blind placebo-controlled trial
Sourceopen_in_newMelville et al. D-aspartic acid supplementation in resistance-trained men over a three month training period. PLoS One. 2017. PMID 28841667.
Population: Twenty-two healthy resistance-trained men aged 18 to 36 years.
Dose protocol: 6 g/day during 12 weeks of supervised resistance training
Key findings: No testosterone, hypertrophy, or strength benefit despite a high-dose, longer-duration protocol.
Notes: Strong modern negative trial in resistance-trained men.
Paper content
This 12-week RCT tested a high DAA dose in resistance-trained men during supervised training. It found no benefit for testosterone, strength, or hypertrophy, reinforcing that DAA is not a reliable testosterone or performance supplement in healthy trained users.
d-aspartic-acid-SRC-004Randomized placebo-controlled trial
Sourceopen_in_newPłoszczyca K, Langfort J, Czuba M, et al. D-aspartic acid supplementation does not improve hormonal or hematological responses during normobaric hypoxia training in male boxers. Nutrients. 2024. PMID:38201906.
Population: Sixteen trained male boxers completing a short D-aspartic acid protocol before and during normobaric hypoxia exposure.
Dose protocol: 6 g/day for 14 days before 11 days of normobaric hypoxia in trained male boxers
Key findings: No meaningful testosterone, cortisol, or hematologic protection signal during hypoxic training stress.
Notes: Extends the modern null pattern beyond standard gym-trained cohorts.
Paper content
This boxer study extends the modern null pattern for D-aspartic acid. Even in a more stressful hypoxia-training context, supplementation did not produce useful hormonal or hematologic benefits.