BackgroundA proprietary composition GMCT contains extracts of two popular Asian herbs viz., Garcinia mangostana (GM) fruit rind and Cinnamomum tamala (CT) leaf. We systematically evaluated physical performance and muscle strength enhancing ability of GMCT in a preclinical mouse model followed by a 42-days double-blind placebo controlled human trial in resistance trained adult males.MethodsFour groups of Swiss albino mice (20–30 g body weight) (n = 6) were fed a standard laboratory diet and given Carboxymethylcellulose sodium (CMC), 150 mg/kg GMCT (GMCT-150), 300 mg/kg GMCT (GMCT-300) or 50 mg/kg Oxymetholone (OXY) via oral gavage for 21 days. On day 22, the animals’ physical performance and muscle strength were assessed in a forced swimming test (FST) and forelimb grip strength experiment, respectively.In the human trial, thirty-eight resistance-trained young adults (mean age 26.32 ± 4.39 years, body weight 67.79 ± 12.84 kg, BMI 22.92 ± 3.54 kg/m2) completed the trial. The participants received either GMCT (n = 19; 800 mg daily) or matched placebo (n = 19) for 42 days. As primary variables, 1-RM bench press, 1-RM leg press, and leg extension repetitions were measured at baseline and on days 14, 28 and 42 of the intervention. Anthropometric parameters and serum markers such as free testosterone, insulin-like growth factor 1 (IGF-1), insulin and lactate were also measured before and after the intervention.ResultsGMCT-300 mice showed significant improvement in swimming time (GMCT: 395.3 ± 81.70 s vs. CMC: 271.6 ± 56.86 s; p = 0.0166), distance (GMCT: 341.22 ± 65.88 m vs. CMC: 260.84 ± 49.15 m; p = 0.0461) and grip strength (GMCT: 43.92 ± 6.97 N vs. CMC: 35.0 ± 6.92 N; p = 0.0490), compared with the CMC group.At the end of the 42-day human trial, the per protocol analyses reveal that mean changes from baseline 1-RM bench press (GMCT: 23.47 ± 10.07 kg vs. PL: 3.42 ± 2.06 kg; p < 0.0001), leg press (GMCT: 29.32 ± 16.17 kg vs. PL: 5.21 ± 1.72 kg; p < 0.0001), number of leg extension repetitions (GMCT: 6.58 ± 2.57 vs. PL: 2.05 ± 1.22; p < 0.0001) in GMCT group were significantly improved, compared with placebo. Intergroup difference analyses show that the changes from baseline left arm (GMCT: 1.09 ± 0.36 cm vs. PL: 0.68 ± 0.42 cm; p = 0.0023), right arm (GMCT: 1.50 ± 0.44 cm vs. PL: 1.11 ± 0.43 cm; p = 0.0088) circumference and lean mass (GMCT: 2.29 ± 2.09 kg vs. PL: 0.52 ± 2.58 kg; p = 0.0404) in GMCT group were also significantly improved, compared with placebo. In comparison to placebo, GMCT supplementation did not improve free testosterone, IGF-1, insulin or lactate levels. Parameters of clinical biochemistry, hematology, urine and vital signs of the participants were within the normal range.ConclusionGMCT supplementation is effective in increasing muscle strength, muscle size and, total lean mass, as well as endurance performance.Trial Registration.Clinical Trial Registry of India (CTRI/2015/01/005374), Registered on Jan 07, 2015; CTRI Website URL - http://ctri.nic.in

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Background: The demand for safe and efficacious botanical formulations to increase muscle mass, strength, and stamina is increasing among athletes and the general population. The nutraceutical supplements of medicinal plant origin exert minimal health concern. Objective: This randomized, double-blind, placebo-controlled study was aimed to evaluate the ergogenic potential of a proprietary, standardized formulation (LI12542F6) of Sphaeranthus indicus flower head and Mangifera indica stem bark extracts. Methods: Forty male participants 18–40 years of age were assigned to receive either a placebo (n = 20) or 650 mg/day LI12542F6 (n = 20) for 56 days. All participants performed a fixed set of resistance exercises during the intervention. The primary endpoint was the change from baseline muscle strength, assessed by one-repetition maximum (1-RM) bench and leg presses, and handgrip strength. The secondary endpoints included cable pull-down repetitions, time to exhaustion on a treadmill, mid-upper arm circumference (MUAC), body composition using dual-energy x-ray absorptiometry (DEXA), and free testosterone and cortisol levels in serum. Results: Fifty-six days supplementation of LI12542F6 significantly improved baseline bench press (P < 0.0001), leg press (P < 0.0001), handgrip strength (P < 0.0006), number of repetitions (P < 0.0001), and time to exhaustion (P < 0.0008), compared to placebo. Post-trial, the LI12542F6 group also showed significantly increased MUAC and improved body composition and serum hormone levels. The participants’ hematology, clinical chemistry, and vital signs were within the normal range. No adverse events were observed. Conclusion: This study demonstrates that LI12542F6 supplementation significantly increases muscle strength and size and improves endurance in healthy men. Also, LI12542F6 is well-tolerated by the participants.