RESUMO
Dietary supplementation is commonly employed by individuals seeking to improve body composition and exercise performance. The purpose of the present study was to examine the safety and effectiveness of a commercially available dietary supplement designed to promote thermogenesis and fat loss. In a randomized double-blind trial, participants were assigned to consume placebo or a multi-ingredient supplement containing caffeine, green tea extract, l-carnitine, evodiamine and other ingredients that purportedly enhance thermogenesis. The study included acute baseline testing, a 6-week progressive resistance training and supplementation intervention, and post-intervention testing. Laboratory assessments included resting energy expenditure responses to acute supplement ingestion, evaluation of body composition and muscular performance, and analysis of blood variables (metabolic panel, testosterone, estrogen and cortisol). Dependent variables were analyzed using ANOVA with repeated measures. No unfavorable effects of supplementation were reported, and the supplement did not adversely affect safety markers. However, the supplement did not reduce fat mass or increase lean mass relative to placebo. In the supplement group, lower body maximal strength was increased relative to placebo (+18%, d=1.1 vs. +10%, d=0.5), and cortisol concentrations were decreased relative to placebo (-16%; d=-0.4 vs. +15%, d=.75). However, no differences were observed for upper body maximal strength or muscular endurance. REE increased in response to both supplement and placebo ingestion (placebo: +5%; supplement: +11.5%), but the difference between conditions was not statistically significant. Overall, some select parameters may have been beneficially modified by supplementation, but this did not result in superior weight or fat loss over 6 weeks of supplementation and resistance training.
RESUMO
BACKGROUND: Theacrine (1,3,7,9-tetramethyluric acid) is a purine alkaloid found in certain coffee (Coffea) species, fruits (Cupuacu [Theobroma grandiflorum]), and tea (Camellia assamica, var. kucha) that has anti-inflammatory, analgesic, and neuro-locomotor properties. Recent preliminary research has also reported increased feelings of energy, reduced fatigue, and strong effects on improving focus, concentration, and motivation to exercise. The purpose of this study was to examine the safety and non-habituating effects of TeaCrine®, a nature-identical, chemically equivalent bioactive version of theacrine. METHODS: Sixty healthy men (mean ± SD age, height, weight: 22.9 ± 4.7 years, 183.5 ± 9.2 cm, 86.5 ± 13.7 kg) and women (22.3 ± 4.5 years, 165.2 ± 12.3 cm, 69.0 ± 17.4 kg) were placed into one of three groups: placebo (PLA, n = 20), 200 mg TeaCrine® (LD, n = 19) or 300 mg Teacrine® (HD, n = 21) and ingested their respective supplement once daily for 8 weeks. Primary outcomes were fasting clinical safety markers (heart rate, blood pressure, lipid profiles, hematologic blood counts, biomarkers of liver/kidney/immune function) and energy, focus, concentration, anxiety, motivation to exercise, and POMS measured prior to daily dosing to ascertain potential tachyphylactic responses and habituation effects. Data were analyzed via two-way (group × time) ANOVAs and statistical significance was accepted at p < 0.05. RESULTS: All values for clinical safety markers fell within normal limits and no group × time interactions were noted. No evidence of habituation was noted as baseline values for energy, focus, concentration, anxiety, motivation to exercise, and POMS remained stable in all groups across the 8-week study protocol. CONCLUSIONS: These findings support the clinical safety and non-habituating neuro-energetic effects of TeaCrine® supplementation over 8 weeks of daily use (up to 300 mg/day). Moreover, there was no evidence of a tachyphylactic response that is typical of neuroactive agents such as caffeine and other stimulants.
