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Increased Human Growth Hormone After Oral Consumption of an Amino Acid Supplement

Results of a Randomized, Placebo-Controlled, Double-Blind, Crossover Study in Healthy Subjects

Tam, Charmaine S. PhD1,2; Johnson, William D. PhD1; Rood, Jennifer PhD1; Heaton, Amy L. PhD1,3; Greenway, Frank L. MD*,1

doi: 10.1097/MJT.0000000000000893
Original Investigation: PDF Only

Background: Human growth hormone (hGH) is best known for influencing bone and muscle growth, as well as body composition, but the use of recombinant hGH is controversial. Amino acids are a potentially safer alternative; however, preliminary investigations of the effects of oral amino acids on hGH release have been inconclusive. Therefore, we tested the effects of a novel blend of amino acids optimized to increase hGH release.

Study Question: Does an investigational amino acid supplement affect hGH release?

Study Design: This was a randomized, placebo-controlled, double-blind, crossover study that included 16 (12 men, 4 women; age 32 ± 14 years; body mass index 26.4 ± 5.0 kg/m2) healthy participants. All participants received both placebo and the amino acid supplement after an overnight fast and completed all study visits. Treatment order was randomized, and each treatment was separated by a 1-week washout period.

Measures and Outcomes: The primary outcomes were the percent change in hGH from baseline to 120 minutes and the area under the curve of hGH over baseline. Serum hGH was measured using enzyme-linked immunosorbent assay at baseline and 15, 30, 60, 90, and 120 minutes.

Results: At 120 minutes, hGH levels increased by 682% (8-fold) from baseline and were significantly higher than placebo (P = 0.01). In addition, a significantly higher mean area under the curve was observed for the amino acid supplement compared with the placebo [20.4 (95% confidence interval, 19.9–21.0 ng/mL) vs. 19.7 (95% confidence interval, 18.7–20.6 ng/mL); P = 0.04].

Conclusions: These results show that a single dose of the oral amino acid supplement was sufficient to significantly increase hGH levels in healthy adult men and women.

Clinical Trial Registry: NCT01540773.

1Pennington Biomedical Research Center, LSU System, Baton Rouge, LA;

2The Charles Perkins Centre and School of Life and Environmental Sciences, University of Sydney, Sydney, Australia; and

3Sierra Research Group, LLC, Salt Lake City, UT.

Address for correspondence: Frank L Greenway, MD, Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808. E-mail:

This was an investigator-led study funded by Sierra Research Group, LLC, Salt Lake City, UT, a wholly owned subsidiary of Basic Research Holdings, LLC, Salt Lake City, UT. C. S. Tam is also supported by a National Health and Medical Research Centre Early Career Fellowship from Australia (#1037275). W. D. Johnson was also funded in part by 1 U54 GM104940 from the National Institute of General Medical Sciences of the National Institutes of Health, which funds the Louisiana Clinical and Translational Science Center.

C. S. Tam, W. D. Johnson, and J. Rood have no conflict of interest. A. L. Heaton is an employee of Bydex Management, LLC, and participates in an employee long-term incentive plan of Basic Research, LLC. F. L. Greenway is a consultant for Basic Research, LLC, Beachbody, Eisai, Inc, General Nutrition Corporation, Melior Discoveries, and Tech Enterprises; is on the advisory boards of Baronova, Inc, Curves-Jenny Craig, Gelesis, Microbiome Therapeutics, Novo Nordisk, Novartis, PlenSat, and Zafgen; holds stock or stock options in Microbiome Therapeutics, PlenSat, and Zafgen; and holds patents in NeuroQuest.

W. D. Johnson, A. L. Heaton, and F. L. Greenway participated in study design. J. Rood and F. L. Greenway collected data and/or ran samples. W. D. Johnson, J. Rood, and F. L. Greenway took part in data analysis. All authors were involved in data interpretation and critically reviewed the manuscript. All authors had full access to all the data in the study and take responsibility for the integrity of the data and accuracy of the data analysis. All authors have given final approval of the version to be published.

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