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.
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.
Department of Health, Exercise and Biochemical Nutrition Lab, Human Performance, and Recreation, Baylor University, Waco, TX, USA. Electronic address: darryn_willoughby@baylor.edu.
Darryn S
DS
Willoughby
Brian
B
Leutholtz
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001823:Body Composition / Q000187:drug effects*; D026603:D-Aspartic Acid / Q000494:pharmacology*; D019587:Dietary Supplements; D004958:Estradiol / Q000097:blood; D007987:Gonadotropin-Releasing Hormone / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D053580:Muscle Strength / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D055070:Resistance Training; D013739:Testosterone / Q000097:blood; D055815:Young Adult
D006728:Hormones; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D026603:D-Aspartic Acid; D004958:Estradiol; D007986:Luteinizing Hormone
1 repetition maximum; 1-RM; BSA; D-ASP; DDO; ELISA; Estradiol; GnRH; H(2)O(2); HCL; HPG axis; LH; Luteinizing hormone; N-methyl d-aspartic acid; NMDA; Resistance training; Testosterone; bovine serum albumin; d-Aspartic acid; d-aspartate oxidase; d-aspartic acid; enzyme-linked immunoabsorbent assay; gonadotropin-releasing hormone; hydrochloric acid; hydrogen peroxide; hypothalamo-pituitary-gonadal axis; luteinizing hormone