Research

Hormonal

Consuming 20–40g of whey protein immediately after resistance exercise significantly increases myofibrillar fractional synthetic rate (FSR) and activates the AKT/mTOR signaling pathway (AKT, mTOR, 4E-BP1, p70S6K, rpS6) in healthy adults, thereby extending the post-exercise anabolic window.

For healthy adults engaging in resistance training, consuming 20-40g of whey protein around your workout (either immediately after or up to 45 minutes before) significantly boosts muscle protein synthesis compared to placebo. This strategy activates the AKT/mTOR pathway, which drives muscle repair and growth. You do not need to consume excessive amounts (>40g) to see benefits, and pre-workout consumption may even offer a slight edge in FSR magnitude for some protocols.

GoodSupportsHIGH confidence
The combination of whey protein supplementation and exercise improves MPS in a time- and dose-dependent manner. Consumption of 20–40g of whey protein before multiple sets of resistance exercise may enhance myofibrillar FSR and activate the AKT/mTOR pathway, thereby augmenting MPS and extending the anabolic window.
Xiaorong Ji et al. · Nutrients · 2025

Why this rating

Based on a systematic review and meta-analysis of 21 RCTs, though heterogeneity was high (I2 > 70% for most outcomes).

Source

Whey Protein Supplementation Combined with Exercise on Muscle Protein Synthesis and the AKT/mTOR Pathway in Healthy Adults: A Systematic Review and Meta-Analysis

Xiaorong Ji et al. · Nutrients · 2025

DOI 10.3390/nu17162579

Meta-analysis · 21 studiesCited 5×
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DOI resolved against Crossref · corpus check 2026-06-10

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