Effects of Casein Hydrolysate Containing Val-Pro-Pro and Ile-Pro-Pro on Muscle Pump, Muscle Hypertrophy, and Motivation in Resistance-Trained Men: A Placebo-Controlled, Double-Blind, Parallel-Group Comparison Study

Introduction: The purpose was to investigate the effects of lactotripeptides (LTP) immediately after training. Methods: This randomized, placebo-controlled, double-blind, parallel-group comparison study included males who undertook leg strength training every 2 weeks for ≥3 months. Thirty-six participants received placebo, low-dose (LD) (Val-Pro-Pro 0.7 mg/Ile-Pro-Pro 1.0 mg) or high-dose (HD) (Val-Pro-Pro 1.4 mg/Ile-Pro-Pro 2.0 mg) lactotripeptides daily for 4 weeks. Muscle pump, muscle hypertrophy, fatigue, and training motivation were evaluated. Results: In the HD group, thigh circumference before exercise, lean body mass versus baseline and thigh circumference after exercise versus placebo significantly increased (p=0.002, 0.031, 0.032). In the LD group, subjective questionnaire scores related to muscle pump versus placebo significantly improved (p=0.042). Thigh circumference changes, before and after exercise, and subjective questionnaire scores, regardless of dosage, significantly correlated (p=0.026). Individuals with flow-mediated dilation (FMD)