Aspartic Acid
Also known as: L-aspartic acid, D-aspartic acid, D-Asp, aspartate, N-acetyl-aspartic acid
Effective Dosage
No established dose from provided studies
What the Science Says
Aspartic acid is a naturally occurring amino acid that plays roles in energy metabolism and neurotransmitter function. The D-form (D-aspartic acid) has been studied in men with idiopathic infertility, where one small clinical trial found that 2660 mg daily (combined with ubiquinol and zinc) significantly improved progressive sperm motility and raised total testosterone levels over 3 months. It also appears in metabolomics research as a biomarker in various disease states, though this does not mean supplementing it treats those conditions.
What It Doesn't Do
Won't reliably boost testosterone in healthy men with normal levels. Not proven to build muscle or improve athletic performance. The infertility study used a combination product — you can't credit D-aspartic acid alone. Being a biomarker in a disease doesn't mean taking it as a supplement treats that disease.
Evidence-Based Benefits
Aspartic acid is an amino acid that plays a role in the synthesis of proteins and the production of hormones. Some studies suggest it may enhance athletic performance and support testosterone production, particularly in men. However, results are mixed and further research is needed to establish definitive benefits.
Moderate EvidenceEffective at: 3-6 g daily
Source: auto-research
Absorption & Bioavailability
Unknown — no pharmacokinetic or absorption data provided in the supplied studies
Red Flags to Watch For
- The only clinical trial showing testosterone benefits used a combination product (D-aspartic acid + ubiquinol + zinc), making it impossible to isolate aspartic acid's contribution
- Small sample size in the infertility trial (24 per group) limits confidence in the findings
- Widely marketed for testosterone boosting in healthy athletes, but no provided evidence supports this use
- Aspartic acid appears as a disease biomarker in metabolomics studies — this is often misrepresented in marketing as evidence of therapeutic benefit
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06