D-Aspartic Acid
Also known as: DAA, D-aspartate, sodium D-aspartate
The D-isomer of aspartic acid, involved in signaling within the hypothalamus and testes. It became popular in testosterone-booster products after a short trial in untrained men reported higher testosterone at 3 g/day. Subsequent controlled trials in resistance-trained men found no change in testosterone, strength, or body composition at 3 g, and a 6 g dose was associated with a decrease. The evidence is mixed to negative, and formulators should not rely on it for hormonal outcomes.
Research summary
Proposed to stimulate hypothalamic GnRH and testicular steroidogenesis; effects were not reproduced in trained men.
Dosage
Daily amounts, of compound.
| Lowest studied | Typical range | Highest studied | Upper limit |
|---|---|---|---|
| — | 3 g | 6 g | — |
3 g/day for 2–12 weeks is the studied dose; 6 g/day was studied and performed worse than placebo on testosterone in one trial. Products almost universally use 3 g.
Source material: synthetic
Format suitability
- Capsule
- Powder
- Tablet
- Softgel
- Gummy
- Liquid
Gram-scale dose; sour and poorly soluble as the free acid, so sodium D-aspartate is used in some drinks. 3 g is about four size-00 capsules.
Formulation notes
Typically bundled with fenugreek, zinc, and vitamin D in men's formulas. No notable formulation interactions.
Sources
Related ingredients
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Typical: 200–400 mg
Fenugreek Seed Extract
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Typical: 500–600 mg
Tribulus Terrestris Extract
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Horny Goat Weed (Epimedium)
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Typical: 500–1,000 mg
Fenugreek Seed Extract (Testofen)
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Typical: 600 mg