This crossover, placebo-controlled, double-blind study involved 16 healthy subjects [12 males, 4 females; 9 Caucasian, 6 African American, 1 other; mean age=32±14 years; body mass index=26.4±5.0 ranging from 19.1 to 36.8kg/m2] (IRB Number 10043). Each subject reported to the Inpatient Unit on two occasions one week apart. After an overnight fast, subjects had an IV line placed and baseline blood samples were drawn at -30, -15, and 0 minutes. Subjects were then asked to swallow the capsules of supplement (the GF-9 compound) or an identical looking placebo. GF-9 is a novel 2.9g/serving blend of l-lysine HCl, l-arginine HCl, oxo-proline, N-acetyl-l-cysteine, l-glutamine, and schizonepeta (aerial parts) powder. Blood was drawn at 15, 30, 60, 90, and 120 minutes for assay. GH was measured at each time point using the Siemens Immulite 2000 (intra-assay CV was 3.72%, inter-assay CV was 5.70%, and the detection limit for GH was 0.05ng/ml).
Mean growth hormone increased 8-fold over baseline (equivalent to 682%) after the supplement from 0.17ng/ml at baseline to 1.33ng/ml at 120 minutes compared to a mean decrease of 52% after placebo from 0.93 to 0.45ng/ml. The mean change in GH levels from baseline to 120 minutes (GH at 120 minutes minus GH at 0 minutes) was 1.15 (95% CI: 0.17, 2.14) ng/ml after the supplement versus -0.48 (-1.47, 0.50) ng/ml after the placebo, demonstrating a statistically significant differential effect (P=0.01). After the supplement, the mean AUC for GH across 120 minutes was 20.43 (95% CI: 19.90, 20.95) ng/ml/min, which was significantly higher (P=0.04) than placebo at 19.67 (18.74, 20.59) ng/ml/min. Overall, 120 minutes after taking the supplement, GH levels were significantly higher in both absolute levels and by AUC.*