Supplementation with soybean peptides, taurine, Pueraria isoflavone, and ginseng saponin complex improves endurance exercise capacity in humans

The purpose of this study was to investigate the effects of a proprietary blend of soybean peptides, taurine, Pueraria isoflavone, and ginseng saponin complex (STPG capsule) on exercise performance in humans. Fourteen male volunteers were randomly assigned to two crossover treatments in which they consumed either four STPG capsules (STPG treatment) or placebo (P treatment) for 15 days before a 75% maximal oxygen uptake (V̇O_{2 max}) exhaustive cycling test. Blood samples and respiratory gas were collected prior to the exercise (Pre-Ex), at 10 (Ex-10), 15 (Ex-15), 20 (Ex-20), and 25 (Ex-25) minutes during exercise, and immediately after exercise (exhaustion) to assess the blood metabolites, cardiorespiratory responses, and energy substrate utilization. The result showed that exercise time to exhaustion of the 75% V̇O_{2 max} exhaustive cycling test of the STPG-treated subjects was significantly greater than with the P treatment (30.99 ± 2.01 vs. 28.05 ± 1.48 minutes). The plasma lactate concentrations at Ex-20 and Ex-25 in the STPG treatment were significantly lower with STPG treatment than with P treatment (10.5 ± 0.7 vs. 11.5 ± 0.8 and 10.7 ± 0.9 vs.12.3 ± 1.0 mmol/L, respectively). Nonesterified fatty acid levels at Ex-15, Ex-20, Ex-25, and exhaustion in the STPG group (0.27 ± 0.03, 0.32 ± 0.04, 0.32 ± 0.06, and 0.37 ± 0.05 mmol/L, respectively) were significantly higher than those in the P treatment (0.21 ± 0.03, 0.23 ± 0.03, 0.24 ± 0.03, and 0.25 ± 0.03 mmol/L, respectively). It was concluded that supplementation of four capsules (2 g) of STPG complex, consisting of soybean peptides, taurine, Pueraria isoflavone, and ginseng saponin, for 15 days was effective in promoting utilization of free fatty acids and improving exhaustive cycling test performance in humans.