The Claim
Daily caffeine supplementation at approximately 3 mg/kg taken one hour before thrice-weekly upper-body resistance training in recreationally active men increases biceps and triceps muscle thickness by a statistically significant amount compared to placebo over a six-week period.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
In recreationally active men, taking 3 mg of caffeine per kilogram of body weight one hour before three weekly upper-body weightlifting sessions for six weeks results in greater increases in biceps and triceps muscle thickness compared to taking a placebo.
See the scientific wording
Six weeks of daily caffeine supplementation (approximately 3 mg/kg) taken one hour before thrice-weekly upper-body resistance training in recreationally active men increases biceps and triceps muscle thickness by a statistically significant amount, with a greater effect observed in the caffeine group compared to placebo, suggesting caffeine may enhance muscle hypertrophy independent of strength gains.
Caffeine increases calcium release inside muscle cells during exercise, which turns on a key protein-building switch called mTOR, leading to more muscle growth even without stronger contractions.
What the research says
1 studyTaking caffeine before arm workouts three times a week for six weeks helped men build bigger biceps and triceps, even though they didn’t get stronger than those who took a sugar pill.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.