Do you need protein straight after training?
What the studies we have published say — strongest evidence first. Every claim below links to the paper it came from.
Pooled trials show whey protein combined with exercise raises muscle protein synthesis in healthy adults, with a dose-dependent effect across 10 to 60 g and rises of up to 2.5-fold when 20-40 g is taken 45 minutes before multiple-set resistance exercise.
well supported · human dataSolid enough to take seriously: results pooled from 21 trials in healthy adults, with muscle building measured directly in biopsy samples. A bigger synthesis response over a few hours is not the same as more muscle after months of training, so the long-term payoff is still unproven.
A network meta-analysis of 116 trials in 4,711 adults doing resistance training found protein taken after exercise was most effective for gaining muscle mass, protein at night was most effective for strength, and milk proteins were among the best types; no timing or type improved physical performance tests.
well supported · human dataSolid for muscle and strength, but the rankings come mostly from indirect comparisons because trials rarely pitted one timing against another directly. It pools 116 trials in 4,711 adults doing resistance training, and the evidence was rated moderate certainty.
In a 12-week randomised trial, 23 resistance-trained adults bulking on a 16:8 time-restricted eating schedule gained similar fat-free mass, muscle mass and 1RM strength to controls, but significantly less body weight and fat mass. The time-restricted group ate fewer calories, protein and carbohydrate than prescribed, so the smaller fat gain reflects intake falling short of the target surplus rather than meal timing itself.
preliminary · human dataSmall 12-week RCT in 23 healthy resistance-trained individuals, with body composition measured by single-frequency bioelectrical impedance; the eating-window group failed to hit the prescribed energy surplus, so the fat-mass difference is confounded by lower intake.
Young men taking protein with carbohydrate during their workouts gained no more muscle fibre size, lean mass or strength over 8 weeks than men taking carbohydrate alone with the same calories. The resistance training itself worked well in both groups, raising lean mass, strength, VO2max, fat oxidation and fibre cross-sectional area.
preliminary · human dataSmall exploratory RCT: just 17 physically active young men (8 vs 9) over 8 weeks, which the authors say cannot exclude modest effects; a null result from an underpowered trial, not proof of no benefit.
Across 22 randomised trials, adding protein supplementation to exercise training improved frailty status, lean mass, leg strength and walking speed in frail older adults. Protein paired with resistance training gave the clearest lean mass gains.
well supported · human dataSolid for direction, modest in size: results pooled from 22 trials where frail older people were assigned at random to protein plus exercise or a comparison group. Study quality averaged 6.7 out of 10 and the programmes varied, so the best formula is still unsettled.
A systematic review of seven randomised trials in 260 older adults found that resistance training three times a week, combined with at least 15 g of daily protein mostly from dairy, reduced blood markers that drive muscle loss and raised those that build it, alongside gains in strength, fat-free mass and muscle fibre size.
well supported · human dataPromising but thin: a sweep of all the studies turned up just seven trials with 260 older adults between them, and they varied in length and design. The direction is consistent; the ideal amount of protein or training is not settled here.
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This page collects what our published, cited studies say; it is information, not medical advice. Have a different question? Ask it here.