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06.06.2015

6 g D-Aspartic Acid a day lowers testosterone levels

Evidence is mounting that D-Aspartic Acid supplementation does not raise bodybuilders' testosterone levels. Researchers at the University of Western Sydney have confirmed that the eccentric amino acid doesn't live up to expectations. In the human study they published in the Journal of the International Society of Sports Nutrition high doses of D-Aspartic Acid actually lowered the testosterone level.

Study
The Australians did an experiment with 24 young men aged between 18 and 36. The men had all been doing weight training for at least 2 years and could lift more than their own bodyweight on the bench presses.

The researchers divided their subjects into three groups of eight men. One group took a placebo for two weeks, the second group took 3 g D-Aspartic Acid daily and the third group took 6 g D-Aspartic Acid every day. [The structural formula of D-Aspartic Acid is shown above.] The subjects took the supplements with breakfast.

Results
The 3-g dose of D-Aspartic Acid had no effect on the subjects' testosterone level the researchers discovered. The 6-g dose did have an effect, but not what you'd expect: the supplement lowered the subjects' testosterone level.

The researchers also measured the amount of estradiol and albumin in the subjects' blood. D-Aspartic Acid had no effect on either of these.

Conclusion
"The need for longer-duration research utilising six grams of D-Aspartic Acid is clear", the researchers summarised. "Future research should explore supplementation of 6 g D-Aspartic Acid per day over a longer period and observe any correlations between basal testosterone levels and changes in hypertrophy and strength."

Source:
J Int Soc Sports Nutr. 2015 Apr 1;12:15.

More:
N-Methyl-D-Aspartic Acid has zilch effect on testosterone level 12.11.2014
D-Aspartic Acid not effective in young bodybuilders 16.10.2013
Three grams D-aspartic acid raises testosterone levels by forty percent 20.11.2009