D-Aspartic Acid (DAA) Supplements & Testosterone

D-Aspartic Acid (DAA) Does Not Boost Testosterone

A few years ago D-Aspartic Acid, also known as D-Aspartate and DAA, absolutely took off as the latest must have testosterone booster for men thanks to a highly touted study, one of which was paid for by a manufacturer of DAA (no surprise there).

Unfortunately, as is often the case, supplement companies showcased what they wanted you to see and left off most of the relevant information.

Let’s take a look at the full scope of the human based case studies.

DAA and Sperm Quality

If you are an infertile man and trying to have a baby DAA seems to be a great supplement to take.

In a human based case study involving 30 infertile men, supplementation of DAA for 90 days improved the amount of and motility of their sperm.

These men also saw a “significantly increased number of pregnancies” from supplementation. These same men also saw a brief increase in testosterone production but it returned to baseline after about 2 weeks. (1)

It is both the fact the study was done on men who were infertile and the fact their T levels returned to where they were previously, after a very short time that fails to get mentioned!

However, if you are struggling to conceive, supplementing with D-Aspartic Acid is certainly worth trying.

Does D-Aspartic Acid (DAA) Boost Testosterone?

D-Aspartic Acid may boost testosterone in infertile men but the increase only lasted for 2 weeks and then quickly returned to baseline. In another human case study, D-Aspartic Acid significantly lowered total and free testosterone!

24 healthy men with a minimum of 2 years of weight lifting experience were split into 3 different groups. Some men received a placebo and the other men were given either 3 or 6 grams of DAA.

The men who were given 3 grams of D-Aspartic Acid saw neither a gain nor decrease in testosterone levels, however, the men who received 6 grams saw a decrease in T levels. (2)

In the only other human based study I could find, healthy males were put through a 28 day weight lifting program where they trained 4 times per week and were split into two groups.

  1. Men received 3 grams daily of DAA
  2. Men received 3 grams daily of a placebo

In both groups the men saw a significant increase in body composition and muscle strength, however, there was no difference between group 1 and 2.

Total and free testosterone levels were also measured as well as luteinizing hormone (LH) which stimulates the testicles to produce T.

The researchers found that both total and free T levels were unchanged with resistance training and D-Aspartic Acid supplementation. Luteinizing hormone was unchanged as well. (3)


I haven’t seen any research which proves D-Aspartic Acid increases free or total testosterone in relatively healthy men and in fact there is evidence it may actually decrease testosterone production.

Based on the human case studies at hand, it is my opinion you are better off saving your money and not buying into the hype.

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  1. D’Aniello, G., et al., D-Aspartate, a Key Element for the Improvement of Sperm Quality. Advances in Sexual Medicine, 2012. 02(04): p. 45. – Link
  2. Melville, Geoffrey W, et al. “Three and Six Grams Supplementation of d-Aspartic Acid in Resistance Trained Men.” Journal of the International Society of Sports Nutrition, vol. 12, no. 1, Jan. 2015 – Link
  3. Willoughby, D.S. and B. Leutholtz, D-aspartic acid supplementation combined with 28 days of heavy resistance training has no effect on body composition, muscle strength, and serum hormones associated with the hypothalamo-pituitary-gonadal axis in resistance-trained men. Nutr Res, 2013. 33(10): p. 803-10. – Link