PHYS-21 · Principle
Do I need a protein shake within 30 minutes of lifting?
No. In meta-analyses the day's protein total, with the training, decided the gain; timing added nothing once total intake was counted. Older muscle needs bigger doses.
How the body works, agreed across the reviews below; a study entry shows what one experiment measured.
Practical Application
Do I need a protein shake within 30 minutes of lifting? No. In meta-analyses the day's protein total, with the training, decided the gain; timing added nothing once total intake was counted. Older muscle needs bigger doses.
What it does not mean: that a missed shake erases a session, or that more protein builds more without limit (across 49 trials the gain levelled off at a moderate daily total, REF-579).
Mechanism
Resistance exercise grows muscle mainly through an mTORC1-mediated rise in protein synthesis; mechanical signals are the prime candidate stimuli, damage is probably not essential, the metabolite case indirect (REF-682); ribosome biogenesis and myonuclear accretion take part too, with open disagreements (Roberts et al. 2023).
Across 20 strength and 23 hypertrophy trials, protein near the session had no effect once covariates were controlled; total protein intake best predicted growth (Schoenfeld, Aragon & Krieger 2013); the anabolic effect of exercise lasts at least 24 h (REF-578).
After exercise, 100 g of protein raised muscle protein synthesis more and for over 12 h compared with 25 g, with negligible extra oxidation (Trommelen et al. 2023, one tracer study).
Common misreading
"The anabolic window closes in 30 minutes"; "the body can only use 20-25 g at a time"; "the pump is what grows muscle".