Impact Of Acute Turkesterone Dosing On Serum IGF-1 And Subjective Digestibility Scores In Recreationally-Active Males

Turkesterone is a relatively novel and increasingly popular phytoecdysteroid compound amongst recreationally active demographics. Despite prior in vitro data suggesting that this compound may support enhanced body composition via insulin-like growth factor 1 (IGF-1)-mediated protein synthesis, no human evidence exists in this regard nor how well its digestibility is tolerated. PURPOSE: To determine the effect of multiple turkesterone doses on serum IGF-1 and to report any gastrointestinal (GI) distress symptoms in healthy humans. METHODS: Eleven recreationally active males (23.3±2.2y) visited the laboratory on three occasions separated by at least seven days and were randomized in single-blind, placebo-controlled, and counter-balanced crossover fashion to either 2000mg cellulose placebo (PLA), 1000mg turkesterone + 1000mg placebo, (1000T) or 2000mg (2000T) turkesterone. Venous blood was sampled to determine serum IGF-1 concentrations and a GI distress questionnaire (nausea, vomiting, heartburn symptoms, etc.) was administered both at baseline (PRE), as well as 3-hours (POST3H) and 24-hours (POST24H) post-acute supplementation at each visit. Serum IGF-1 was analyzed using a two-way (condition [PLA, 1000T, 2000T] x time [PRE, POST3H, POST24H]) ANOVA with repeated measures at a significance level of p<0.05. RESULTS: Analyses revealed no significant condition (p=.180; ηp2=0.228), time (p=0.227; ηp2=.390), nor interaction effects (p=0.547; ηp2=0.211) for serum IGF-1. Moreover, no participants reported any GI distress symptoms across any condition and/or time permutation. Although non-significant, mean changes from PRE to POST3H and POST24H were markedly higher in the 1000T (17.8±53.1ng/ml and 11.2±53.0ng/ml, respectively) and 2000T (31.6±59.3ng/ml and 24.5±49.4ng/ml, respectively) versus the PLA group (0.76±24.4ng/ml and -1.30±36.5ng/ml, respectively). CONCLUSION: Multiple acute turkesterone supplementation doses resulted in no enhancement in serum IGF-1 concentrations but was digestively tolerated in young recreationally-active human males. Nonetheless, there were mean differences that should be explored to determine any longitudinal and/or exercise-dependent permissive impacts on relevant anabolism-associated biomarkers. The present research was funded by both the Baylor University Health, Human Performance, and Recreation Department Master's Thesis Research Grant and the Texas Chapter of the American College of Sports Medicine (ACSM) Student Development and Research Award.