D
Muscle Mass/Strength
Systematic review: DAA cannot alter body composition in trained males; strength gains from training only
3 studies80 participants
none
Aspartate
D-aspartic acid (DAA) is the D-enantiomer of aspartic acid concentrated at nmol/g levels in adenohypophysis, hypothalamus, brain, and testes, where it modulates the hypothalamic-pituitary-gonadal (HPG) axis. DAA is converted by D-aspartate methyltransferase to N-methyl-D-aspartic acid (NMDA), which is ~100x more potent and acts on NMDA receptors to stimulate GnRH release from hypothalamus, LH from pituitary, and testosterone synthesis in testes via cAMP/ERK1/2 signaling. In animals, D-Asp promotes spermatogenesis via GluR/ERK1/2 pathway activation and enhances StAR and steroidogenic enzyme expression. One 12-day study in untrained men (n=23) showed 33% LH and 42% testosterone increase at 3g/day (PMID: 19860889), but a systematic review of 4 RCTs in resistance-trained men found no effect at 3-6g/day (PMID: 28215945). D-Asp concentration is significantly higher in normospermic vs oligoasthenoteratospermic men, suggesting a role in sperm quality. Combination therapy (DAA+ubiquinol+zinc) improved sperm motility in infertile men. Also stimulates growth hormone and prolactin release from pituitary (PMID: 17118457).
Quick Answer
What it is
D-aspartic acid (DAA) is the D-enantiomer of aspartic acid concentrated at nmol/g levels in adenohypophysis, hypothalamus, brain, and testes, where it modulates the hypothalamic-pituitary-gonadal (HPG) axis. DAA is converted by D-aspartate methyltransferase to N-methyl-D-aspartic acid (NMDA), which is ~100x more potent and acts on NMDA receptors to stimulate GnRH release from hypothalamus, LH from pituitary, and testosterone synthesis in testes via cAMP/ERK1/2 signaling.
Key findings
- Grade C: Sperm Motility (Infertility)
- Grade C: Serum Testosterone (Untrained Men) (Low Testosterone)
- Grade D: Serum Testosterone (Trained Athletes) (Low Testosterone)
Safety
No specific caution or interaction language was detected in the current summary/outcome notes.
ℹ️ Quick Facts: Aspartate
Quick Facts: Aspartate
- Best Evidence:Grade C
- Conditions Studied:3
- Research Outcomes:4
- Key Effect:Low Testosterone
Outcomes by grade:
A0
B0
C2
D2
3 conditions · 4 outcomes
Detailed Outcomes
|
C
Sperm Motility
2660mg DAA + ubiquinol + zinc improved progressive sperm motility and testosterone (p=0.009) over 3 months
2 studies90 participants
moderate↑Improves
C
Serum Testosterone (Untrained Men)
42% increase in testosterone after 12 days of 3.12g/day in untrained men; LH increased 33%
1 study23 participants
moderate↑Improves
D
Serum Testosterone (Trained Athletes)
No increase in testosterone in resistance-trained men; 6g/day actually decreased total and free testosterone
4 studies100 participants
none
Evidence by Condition
Best grade per condition (each condition may have multiple outcomes)
Research Citations (11)
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