Research

Hormonal

Animal-based proteins provide a modest but statistically significant advantage in stimulating muscle protein synthesis (MPS) compared to plant-based proteins, primarily driven by higher leucine content and bioavailability.

If you are over 65, prioritize animal proteins (whey, milk, eggs) or ensure your plant protein is high-leucine (soy, pea blends) to maximize muscle growth. For younger adults, plant and animal proteins appear functionally equivalent for MPS when doses are matched.

ModerateQualifiesLOW confidence
animal-based proteins showed a modest advantage for fractional synthesis rate (FSR %·h⁻¹), though with a negligible effect size (ESPlant:Animal = 0.004 [95%CrI: -0.002 to 0.011]; p(>0) = 0.899).
Bricia Mendes et al. · 2025

Why this rating

Systematic review with meta-analysis, but GRADE assessment rated certainty as 'low' due to imprecision and heterogeneity.

Source

Effects of plant- versus animal-based proteins on muscle protein synthesis

Bricia Mendes et al. · 2025

DOI 10.51224/srxiv.526

Meta-analysis · 12 studies
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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