Caffeine dosing strategies investigated for impact on resistance training adaptations in young men

Resistance training is a cornerstone for muscle hypertrophy and strength. While caffeine is a widely used ergogenic aid, optimal dosing strategies for maximizing long-term training adaptations, beyond acute performance, remain unclear. Current recommendations often focus on pre-exercise timing, but sustained or varied intake patterns might differentially influence anabolic signaling pathways, recovery, and overall training efficacy. This trial addresses the gap in understanding how different chronic caffeine regimens affect integrated anabolism and hypertrophy.

This randomized, double-blind, placebo-controlled crossover trial enrolls 180 caffeine-naive, inactive young adult males. Participants complete two 4-week supervised resistance training programs, separated by a 2-week washout. Three caffeine strategies are tested: (1) constant daily low-moderate dosing (3 mg/kg/day), (2) gradually escalating dose (3 to 6 mg/kg across weeks), and (3) training-day-only caffeine (3 mg/kg/day). Primary endpoints are non-invasive measures of integrated anabolism/hypertrophy (D2O-derived plasma proteomic fractional synthesis rate, DXA muscle volume) and strength. Secondary outcomes include hormonal responses (insulin, cortisol, testosterone, IGF-1), sleep, recovery, and adverse effects.

This is a description of a planned clinical trial, and as such, no results are available yet. The study aims to investigate the effects of different caffeine supplementation strategies on resistance training adaptations. Findings will be reported upon completion of the trial.