Precise protein supplementation strategies for muscle improvement are still lacking. The timing or type of protein supplementation has been debated as a window of opportunity to improve muscle mass, strength, and physical performance. We conducted a network meta-analysis of randomized controlled trials with protein supplements and resistance training. PubMed, Web of Science, Cochrane Library, and SPORTDiscus databases were searched until May 1, 2023. We included 116 eligible trials with 4,711 participants that reported on 11 timing and 14 types of protein supplementation. Compared with placebo, protein supplementation after exercise (mean difference [MD]: 0.54 kg [95% confidence intervals 0.10, 0.99] for fat-free mass, MD: 0.34 kg [95% confidence intervals 0.10, 0.58] for skeletal muscle mass) and at night (MD: 2.85 kg [0.49, 5.22] for handgrip strength, MD: 12.12 kg [3.26, 20.99] for leg press strength) was most effective in improving muscle mass and strength, respectively (moderate certainty). Milk proteins (milk, whey protein, yogurt, casein, and bovine colostrum), red meat, and mixed protein were effective for gains in both muscle mass and strength (moderate certainty). No timing or type of protein showed a significant enhancement in physical performance (timed up-to-go test, 6-min walk test, and gait speed). Pre/postexercise and Night are key recommended times of protein intake to increase muscle mass and strength, respectively. Milk proteins are the preferred types of protein supplements for improving muscle mass and strength. Future randomized controlled trials that directly compare the effects of protein timing or types are needed. This trial was registered at International Prospective Register of Systematic Reviews as CRD42022358766.

目前仍缺乏改善肌肉的精确蛋白质补充策略。补充蛋白质的时间或类型一直被认为是改善肌肉质量、力量和身体表现的机会之窗。我们对蛋白质补充剂和阻力训练的随机对照试验进行了网络荟萃分析。PubMed、Web of Science、Cochrane Library 和 SPORTDiscus 数据库的检索截止日期为 2023 年 5 月 1 日。我们纳入了 116 项符合条件的试验，涉及 4,711 名参与者，报告了 11 种时机和 14 种类型的蛋白质补充。与安慰剂相比，运动后补充蛋白质（平均差 [MD]：去脂质量为 0.54 kg [95% 置信区间 0.10, 0.99]，MD：骨骼肌质量为 0.34 kg [95% 置信区间 0.10, 0.58]）晚上（MD：握力2.85公斤[0.49，5.22]，腿举力量MD：12.12公斤[3.26，20.99]）分别对改善肌肉质量和力量最有效（中等确定性）。牛奶蛋白（牛奶、乳清蛋白、酸奶、酪蛋白和牛初乳）、红肉和混合蛋白对于增加肌肉质量和力量均有效（中等确定性）。没有任何时间或类型的蛋白质显示出身体表现的显着增强（定时起身测试、6 分钟步行测试和步态速度）。运动前/运动后和夜间分别是建议摄入蛋白质以增加肌肉质量和力量的关键时间。牛奶蛋白是改善肌肉质量和力量的首选蛋白质补充剂。未来需要直接比较蛋白质时间或类型的影响的随机对照试验。该试验在国际前瞻性系统评价登记册上注册为 CRD42022358766。