Whey Protein and Increased Lean Mass

Research synthesisLow evidenceSmall effect3 studies · 1 beneficial · 2 neutral · 0 harmful

Across 3 studies, 1 reported a beneficial moderate-sized effect on increased lean mass (45 g/day in young untrained males), while 2 reported neutral small effects (including a large meta-analysis in older adults). Median study duration was 84 days. The overall evidence is mixed, with no consistent effect across populations.

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Additionally, only 1 of 3 studies reached statistical significance, suggesting the effect may be smaller than reported in that single beneficial study.

Generated Jun 11, 2026

Doses used in studies

g single-dose: 24 (median 24, IQR 24–24) — 1 study
g/day: 45 (median 45, IQR 45–45) — 1 study

Time to effect

Median: 2.8 months · IQR 2.8 months–2.8 months · Range 2.8 months–2.8 months — Reported in 2 of 3 studies

3 of 3 papersPopulation:

Explore the Optimal Treatment Regimen Across Combinations of Variate Protein Sources and Exercise Modalities and Its Associated Factors in Older Adults: A Network Meta-Analysis and Meta-Regression of Randomized Controlled Trials.
- 2026-04-29
- Meta-Analysis · n = 980
- Nutrients 18(9)
- - Che-Li Lin
  - Shih-Wei Huang
  - Hung-Chou Chen
  - Mao-Hua Huang
  - Tsan-Hon Liou
  - Chun-De Liao
- PubMed: 42124009
- DOI: 10.3390/nu18091409
6 Insights on
- Increased Lean Mass
- High evidence
- Rigorous Journal
- Elderly
This paper determined the optimal regimen among the composites of variate protein sources ... (milk was among the 10 sources analyzed; network meta-analysis includes all sources and the conclusion singled out whey, implying milk did not show a significant large effect).
Effect
Neutral
Effect size
Small
Significant
No
Post-Exercise Whey Protein Supplementation: Effects on IGF-1, Strength, and Body Composition in Pre-Menopausal Women, a Randomised Controlled Trial.
- 2025-06-18
- RCT
- Nutrients 17(12)
- - Marc Murray
  - Lara Vlietstra
  - Alyssa M D Best
  - Stacy T Sims
  - James A Loehr
  - Nancy J Rehrer
- PubMed: 40573144
- DOI: 10.3390/nu17122033
6 Insights on
- Increased Lean Mass
- High evidence
- Rigorous Journal
- Adults
Total lean mass increased (0.84 ± 0.80 kg, 0.56 ± 1.4 kg, CON, PRO, resp., p = 0.009)
Effect
Neutral
Effect size
Small
Significant
No
Dose
24 g
Similar effects between animal-based and plant-based protein blend as complementary dietary protein on muscle adaptations to resistance training: findings from a randomized clinical trial.
- 2025-10-08
- RCT
- Journal of the International Society of Sports Nutrition 22(1)
- - Martin Hindermann Santini
  - Alice Erwig Leitão
  - Bruna Caruso Mazzolani
  - Fabiana Infante Smaira
  - Mariana Silva Camargo de Souza
  - Andrea Santamaria
  - Bruno Gualano
  - Hamilton Roschel
- PubMed: 41059835
- DOI: 10.1080/15502783.2025.2568047
5 Insights on
- Increased Lean Mass
- High evidence
- Adults
leg lean mass (PLNT: 0.9 kg ±0.2; ANML: 1.3 kg ±0.2)
Effect
Beneficial
Effect size
Moderate
Significant
Yes
Dose
45 g/day (three 15-g daily doses)

Whey Protein and Increased Lean Mass

Explore the Optimal Treatment Regimen Across Combinations of Variate Protein Sources and Exercise Modalities and Its Associated Factors in Older Adults: A Network Meta-Analysis and Meta-Regression of Randomized Controlled Trials.

Post-Exercise Whey Protein Supplementation: Effects on IGF-1, Strength, and Body Composition in Pre-Menopausal Women, a Randomised Controlled Trial.

Similar effects between animal-based and plant-based protein blend as complementary dietary protein on muscle adaptations to resistance training: findings from a randomized clinical trial.