You’re in your early twenties, and you’re looking for a supplement that will boost your testosterone level and thus speed up your muscle bulking. Whatever you do, don’t try D-aspartic acid. According to a small human study published by sports scientists Darryn Willoughby and Brian Leutholtz in Nutrition Research, the effect of D-aspartic acid on testosterone levels is minimal and the same goes for its effect on muscle strength.
You’re in your early twenties, and you’re looking for a supplement that will boost your testosterone level and thus speed up your muscle bulking. Whatever you do, don’t try D-aspartic acid. According to a small human study published by sports scientists Darryn Willoughby and Brian Leutholtz in Nutrition Research, the effect of D-aspartic acid on testosterone levels is minimal and the same goes for its effect on muscle strength.
After an Italian study showed that supplementation with 3 g sodium-D-aspartate boosted testosterone levels in elderly men, D-aspartic acid analogues became a modest rage in the sports supplements world. Experiences with pure D-aspartic acid were not particularly hopeful; those with calcium and sodium salts of the amino acid were better. The body absorbs these forms of D-aspartic acid better.
Willoughby and Leutholtz were sceptical about the D-aspartic acid rage. The men in the Italian study had low testosterone levels while bodybuilders generally have a high level as a result of heavy physical training and carefully worked out diets. So is D-aspartic acid effective in this group?
This is the question the researchers tried to answer by doing a 28-day long experiment with 20 recreational bodybuilders whose average age was 22.
The researchers gave half of their subjects 3 g D-aspartic acid daily. The other half of the subjects were given a placebo.
The supplement didn’t work. The tables below show that the increases in testosterone level and strength were negligible. The effects were not significant at all.
The researchers observed that the supplementation only resulted in a limited rise in the subjects’ D-aspartic acid level. What had risen significantly was the level of the enzyme D-aspartate oxidase – an enzyme that breaks down D-aspartic acid in the intestines, kidneys and liver.
So D-aspartic acid doesn’t work, the researchers sum up. “We conclude that 28 days of D-aspartic acid supplementation at a daily dose of 3 g is ineffective in upregulating the activity of the hypothalamo-pituitary-gonadal axis and has no preferential effects in which to increase skeletal muscle mass and strength in resistance-trained men”, they write.
This is the case for the free form of D-aspartic acid. The study has little to say when it comes to the sodium and calcium bound analogues of D-aspartic acid, sodium-D-aspartate and calcium-D-aspartate.
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
Darryn S. WilloughbyCorresponding author contact information, E-mail the corresponding author,
Brian Leutholtz
Department of Health, Exercise and Biochemical Nutrition Lab, Human Performance, and Recreation, Baylor University, Waco, TX, USA
Abstract
It was hypothesized that d-aspartic acid (D-ASP) supplementation would not increase endogenous testosterone levels or improve muscular performance associated with resistance training. Therefore, body composition, muscle strength, and serum hormone levels associated with the hypothalamo-pituitary-gonadal axis were studied after 28 days of resistance training and D-ASP supplementation. Resistance-trained men resistance trained 4 times/wk for 28 days while orally ingesting either 3 g of placebo or 3 g of D-ASP. Data were analyzed with 2 × 2 analysis of variance (P < .05). Before and after resistance training and supplementation, body composition and muscle strength, serum gonadal hormones, and serum D-ASP and d-aspartate oxidase (DDO) were determined. Body composition and muscle strength were significantly increased in both groups in response to resistance training (P < .05) but not different from one another (P > .05). Total and free testosterone, luteinizing hormone, gonadotropin-releasing hormone, and estradiol were unchanged with resistance training and D-ASP supplementation (P > .05). For serum D-ASP and DDO, D-ASP resulted in a slight increase compared with baseline levels (P > .05). For the D-ASP group, the levels of serum DDO were significantly increased compared with placebo (P < .05). The gonadal hormones were unaffected by 28 days of D-ASP supplementation and not associated with the observed increases in muscle strength and mass. Therefore, at the dose provided, D-ASP supplementation is ineffective in up-regulating the activity of the hypothalamo-pituitary-gonadal axis and has no anabolic or ergogenic effects in skeletal muscle. Source: http://www.sciencedirect.com
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