Low-dose amino acid supplementation: no effects on serum human growth hormone and insulin in male weightlifters

Int J Sport Nutr. 1993 Sep;3(3):290-7. doi: 10.1123/ijsn.3.3.290.


Using a double-blind, crossover protocol, we studied the possible effects of a 4-day combined L-arginine, L-ornithine, and L-lysine supplementation (each 2 g/day, divided into two daily doses) on 24-hr level of serum human growth hormone (hGH) and insulin in 11 competitive weightlifters, ages 19 to 35 yrs. Three similar daily hGH peaks, seemingly preceded by a decrease in serum insulin concentration, were found during both amino acid and placebo supplementation. Supplementation did not affect the physiological variation of serum hGH concentration (treatment and treatment x time interaction: p = 0.43-0.55). Analogously, serum insulin levels were not higher after amino acid supplementation. Therefore the ergogenic value of low-dose oral amino acid supplementation in increasing hGH or insulin secretion seems questionable.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amino Acids / administration & dosage
  • Amino Acids / pharmacology*
  • Double-Blind Method
  • Drug Administration Schedule
  • Growth Hormone / blood
  • Growth Hormone / drug effects*
  • Humans
  • Insulin / metabolism
  • Male
  • Weight Lifting / physiology*


  • Amino Acids
  • Insulin
  • Growth Hormone