D-Aspartic Acid
Also known as: D-Asp, D-Aspartate
A recent systematic review of many marketed 'testosterone boosters' noted D-aspartic acid among ingredients with only a small number of studies, and overall most proposed boosters did not reliably raise total testosterone. One randomized, double-blind trial of a combination product containing 2660 mg D-aspartic acid plus ubiquinol and zinc reported increased total testosterone and improved progressive sperm motility in infertile men after 3 months, but the intervention was a combination so effects cannot be attributed to D-aspartic acid alone. Overall human evidence is sparse and heterogeneous.
Last reviewed: 2026-10-14 · 2 indexed studies
Set your location for accurate regulatory status
Saved on this device — no sign-in needed.
Overview
D-aspartic acid (D-Asp) is an endogenous amino acid found in neuroendocrine tissues and reproductive organs. It is marketed in supplements aimed at raising testosterone or improving male fertility, but clinical evidence from human trials is limited and mixed.
Mechanism & Function
Mechanism of Action
Not directly established in the provided abstracts. D-aspartic acid is cited in the literature as an endogenous amino acid present in tissues involved in hormonal regulation; specific mechanistic claims are not reported in the supplied abstracts.
Physiological Role
Endogenous amino acid present in neuroendocrine and reproductive tissues; suggested role in processes related to male reproductive physiology in preclinical literature but not detailed in the supplied abstracts.
Primary Pathways
Performance / Health Relevance
Clinical evidence in humans is inadequate to conclude that D-aspartic acid reliably improves testosterone-dependent performance outcomes. One combination-product trial in infertile men reported improved sperm motility and higher total testosterone, but attribution to D-aspartic acid alone is not possible from that study.
Evidence Review
Practical Use & Dosage
- Minimum Effective Dose
- Not established from the provided abstracts
- Optimal Range
- Not established
- Upper / Caution Level
- Not established
- Timing
- Not established
- Best Format
- Oral
- Bioavailability
- No bioavailability data reported in the supplied abstracts
- Absorption Considerations
- Not described in the supplied abstracts
Safety & Interactions
Monitoring
The provided abstracts do not report detailed safety or adverse event data for D-aspartic acid alone. Where combination products were used, attribution of benefits or harms to D-aspartic acid cannot be determined.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is D-Aspartic Acid typically used or indicated?
D-Aspartic Acid is most commonly used for: Support for male hormonal function, Male fertility / semen parameters, Athletic performance (marketed). Endogenous amino acid present in neuroendocrine and reproductive tissues; suggested role in processes related to male reproductive physiology in preclinical literature but not detailed in the supplied abstracts.
How does D-Aspartic Acid work?
Not directly established in the provided abstracts. D-aspartic acid is cited in the literature as an endogenous amino acid present in tissues involved in hormonal regulation; specific mechanistic claims are not reported in the supplied abstracts.
What is the recommended dose of D-Aspartic Acid?
The optimal range is Not established. with a minimum effective dose of Not established from the provided abstracts. Best taken: Not established. Upper / caution level: Not established.
Does D-Aspartic Acid have side effects?
See safety section.
How strong is the evidence for D-Aspartic Acid?
Evidence level: Limited (overall score 46/100), based on 2 indexed studies on SuppIndex.
Research & References (2)
Do "testosterone boosters" really increase serum total testosterone? A systematic review.
Systematic review of marketed 'testosterone boosters' that included D-aspartic acid among the examined ingredients; pooled assessment covered multiple supplements and populations.
Evaluation of in vivo supplementation of 2660 mg D-aspartic acid and 200 mg ubiquinol and 10 mg zinc on different semen parameters in idiopathic male infertility: a randomized double blind placebo controlled study.
Randomized, double-blind, placebo-controlled trial in idiopathic infertile men evaluating daily supplementation of 2660 mg D-aspartic acid plus 200 mg ubiquinol and 10 mg zinc for 3 months versus placebo.
Related Ingredients
Other top-rated ingredients in Amino Acids.
L-Leucine
82/100Essential BCAA that activates mTORC1 via Sestrin2 sensing, driving phosphorylation of S6K1 and 4E-BP1, initiating cap-dependent translation and muscle protein synthesis.
Beta-Alanine
78/100A rate-limiting precursor to carnosine (β-alanyl-L-histidine) synthesis, enhancing intramuscular pH buffering capacity during high-intensity anaerobic exercise.
EAA Blend
78/100Free-form blend of 9 EAAs (Leu, Ile, Val, Lys, Met, Phe, Thr, Trp, His) at evidence-based ratios; bypasses gastric digestion for rapid plasma aminoacidaemia.
Research Overview
Limited EvidenceCite this ingredient
One-click citation export in APA, MLA, Chicago, BibTeX, or HTML. The URL below is stable and safe to link.
Stable URL
https://thesuppindex.com/ingredients/d-aspartic-acid
SuppIndex. (2026). D-Aspartic Acid: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/d-aspartic-acid
Based on 2 indexed studies · Evidence level: Limited.
Goal Ratings
Stack Compatibility
Evidence in the supplied abstracts includes D-aspartic acid given together with zinc and ubiquinol; effects reported in that trial may reflect the combination rather than D-aspartic acid alone.