D-Aspartic Acid not effective in young bodybuilders

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.

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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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