Out of 140 non-coded amino acids, D-Aspartic acid has been labelled of recent as the “testosterone booster” of amino acids. More and more, D-Aspartic acid is turning up in natural testosterone booster supplements: and with some good reasons. A solid amount of independent research shows evidence of D-Aspartic acid accelerating and enhancing testosterone synthesis. The way in which D-Aspartic acid is involved in the release of sex hormones has attracted a fine collection of studies. However, it should be noted that the majority of research confirming D-Aspartic acid’s involvement in hormone synthesis has been conducted on rats. All the same, it was demonstrated that D-Asp injected in an adult rat led to an increase in luteinizing hormone (LH), testosterone, progesterone and prolactin  . A noteworthy increase in testosterone and LH synthesis has also been reported with in vitro experiments involving leydig cells and pituitary glands with D-Aspartic acid.
In human trials by Topo in 2009, the research literature does note reports of D-Aspartic acid applied as a dietary supplement for men suffering reproductive issues from inferior semen quality. In 20 out of 23 male subjects (87%) the supplementation of D-aspartic acid caused Luteinizing Hormone in the blood to increase by 33.3% in comparison with baseline values. Luteinizing Hormone is an important hormone which tells the tastes to make more testosterone. And even more interesting and profound, actual testosterone concentrations in blood serum increased considerably after a 12-day treatment with D-Aspartic acid by an amazing 42% – and stayed elevated 3 days after supplementation stopped.
Our Verdict: Highly Recommended
The outcomes of almost a dozen intervention studies in rats and humans does suggest pretty strongly that this is one supplement ingredient to be on the lookout for in your natural testosterone booster supplements. While it is true the studies undertaken have had modest sample sizes, they have been rigorous enough to make a claim for solid efficacy. We are recommending this one and at doses of around 1 to 3grams a day.
 D’Aniello A, DiCosmo A, DiCristo C, et al. Involvement of D-aspartic acid in the synthesis of testosterone in rat testes. Life Sci 1996; 59: 97-104.
 D’Aniello A, Di Fiore MM, Fisher H, et al. Occurrence of D-Aspartic acid and N-methyl-D-aspartic acid in rat neuroendocrine tissues and their role in the modulation of luteinizing hormone and growth hormone release. FASEB J 2000; 14: 699-714.
 Topo 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 Edcrinol 2009; 7: 120-30.