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J Clin Med Res. 2019 Jun;11(6):428-434. doi: 10.14740/jocmr3817. Epub 2019 May 10.

Oral Supplementation Using Gamma-Aminobutyric Acid and Whey Protein Improves Whole Body Fat-Free Mass in Men After Resistance Training.

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R&D Department, Pharma Foods International Co., Ltd, 1-49 Goryo-Ohara, Nishikyo-ku, Kyoto 615-8245, Japan.
College of Sport and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu-shi, Shiga 525-8577, Japan.
Life Science Product Unit, Mitsubishi Corporation, Marunouchi Park Bldg., 6-1, Marunouchi 2-chome, Chiyoda-ku, Tokyo 100-8086, Japan.



Oral gamma-aminobutyric acid (GABA) supplementation increases growth hormone (GH) serum levels and protein synthesis. Therefore, post-exercise supplementation using GABA and protein may help enhance training-induced muscle hypertrophy. We evaluated whether GABA with whey protein enhanced muscular hypertrophy in men after progressive resistance training.


Twenty-one healthy men (26 - 48 years) were randomized to receive whey protein (WP; 10 g) or whey protein + GABA (WP + GABA; 10 g + 100 mg) daily for 12 weeks. Both groups performed resistance training twice per week (three sets of 12 repetitions at 60% of maximal strength; leg press, leg extension, leg curl, chest press, and pull down). Body composition was assessed using dual-energy X-ray absorptiometry.


In the WP + GABA group, resting plasma GH concentrations were significantly elevated at 4 and 8 weeks, compared to baseline. However, resting plasma GH concentrations in the WP group were only significantly elevated at 8 weeks. After 12 weeks, the WP + GABA group exhibited significantly greater increase in whole body fat-free mass than the WP group.


The GABA and whey protein combination was more effective for increasing whole body fat-free mass; daily GABA supplementation may help enhance exercise-induced muscle hypertrophy.


Gamma-aminobutyric acid; Protein; Resistance training; Supplementation; Whey protein

Conflict of interest statement

Maya Sakashita, Utano Nakamura, Noriko Horie, and Mujo Kim are working for Pharma Foods International Co., Ltd. which provided GABA in this study.

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