TCP-600 Supplementation and Performance Response in Professional Football Players

This study will examine whether a 28-day supplementation protocol containing taurine, caffeine, and phosphatidylserine can help professional male football players maintain physical performance, cognitive function, recovery-related readiness, and selected football-specific perceptual-cognitive performance. Participants will be randomly assigned to receive either placebo or a phosphatidylserine-containing multi-ingredient supplement. Before and after the supplementation period, players will complete non-invasive assessments such as sprint testing, reaction-time testing, heart rate variability monitoring, wellness/readiness questionnaires, mental-fatigue measures, and selected football-specific perceptual-cognitive tasks where available. The study is designed as an external validation and extension of responder profiles derived from previous randomized controlled trials. Data from previous trials and this validation cohort will be used to examine whether baseline physical, cognitive, autonomic, fatigue-related, recovery-related, or perceptual-cognitive characteristics can predict which players are most likely to benefit from phosphatidylserine-containing multi-ingredient supplementation.

Inclusion Criteria: * Male professional or highly trained football players aged 18-36 years. * Regular participation in structured football training and team activities. * Minimum of 5 years of structured football training experience. * Regular involvement in club training during the study period. * Medical clearance or no known contraindications to high-intensity exercise testing. * Ability to complete sprint, reaction-time, cognitive-fatigue, heart-rate-variability, wellness/readiness, and selected football-specific perceptual-cognitive assessments where available. * Willingness to maintain usual diet and training habits during the study period. * Willingness to avoid additional ergogenic supplements outside the study protocol during the intervention. * Willingness to follow caffeine restrictions before testing sessions. * Written informed consent provided before participation. Exclusion Criteria: * Current musculoskeletal injury or illness preventing full participation in training or testing. * Musculoskeletal injury within the previous 3 months that may affect sprint, football-specific performance, or perceptual-cognitive testing. * Cardiovascular, metabolic, neurological, psychiatric, or other chronic disease that may affect safety or study outcomes. * Diagnosed sleep disorder. * Use of medication affecting heart rate, autonomic nervous system function, sleep, cognition, or exercise performance. * Known hypersensitivity or intolerance to caffeine, taurine, phosphatidylserine, or any supplement ingredient. * Regular use of ergogenic supplements that cannot be discontinued before and during the study period. * Smoking or regular use of nicotine products. * Participation in another interventional study during the same period. * Inability to comply with supplementation, monitoring, or testing procedures. * Failure to provide written informed consent.