Whey Protein and Increased Insulin-like Growth Factor-1 Level

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

Across 3 studies, 2 reported small beneficial effects of whey protein on increasing insulin-like growth factor-1 (IGF-1) levels, while 1 study found a neutral effect. The median study duration was 126 days (~18 weeks), indicating effects typically observed with longer-term supplementation. Most studies involved older adults (≥65 years) or clinical populations with sarcopenia; one study examined pre-menopausal women with post-exercise dosing.

Studied populations: elderly adults (≥65 years), clinical sarcopenia patients, pre-menopausal women

Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. One neutral study in pre-menopausal women suggests the effect may be population- or context-dependent (post-exercise dosing). The meta-analysis (n=1154) provides stronger support but includes heterogeneous populations and interventions. No consistent dose range emerged across studies.

Generated Jul 12, 2026

Doses used in studies

g single-dose: 24 (median 24, IQR 24–24) — 1 study
g/kg/day: 1.5 (median 1.5, IQR 1.5–1.5) — 1 study

Time to effect

Median: 4.2 months · IQR 3.5 months–4.9 months · Range 2.8 months–5.6 months — Reported in 2 of 3 studies

3 of 3 papersPopulation:

Independent effects of whey protein and alkali supplementation on muscle health in healthy older adults: factorial randomized controlled trial.
- 2026-05
- RCT · n = 128
- The American journal of clinical nutrition 123(5)
- - Lisa Ceglia
  - Elsa Konieczynski
  - Elise Danico
  - Ludovic Trinquart
  - Benjamin Koethe
  - Qingyan Xiang
  - Roger A Fielding
  - William J Evans
  - Mahalakshmi Shankaran
  - Bess Dawson-Hughes
- PubMed: 41780731
- DOI: 10.1016/j.ajcnut.2026.101257
5 Insights on
- Increased Insulin-like Growth Factor-1 Level
- High evidence
- Large Human Trial
- Elderly
24-wk mean IGF-1 level was higher in the WP and KHCO3 groups compared with their respective placebo [WP to placebo-WP difference 14.2 ng/mL (95% CI: 7.5, 21.0; P < 0.01)]
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
1.5 g/kg/d
Improving sarcopenia in older adults: a systematic review and meta-analysis of randomized controlled trials of whey protein supplementation with or without resistance training.
- 2024-04
- Meta-Analysis · n = 1,154
- The journal of nutrition, health & aging 28(4)
- - Ming-Lin Li
  - Fei Zhang
  - Han-Yong Luo
  - Zi-Wei Quan
  - Yi-Fei Wang
  - Le-Tian Huang
  - Jia-He Wang
- PubMed: 38350303
- DOI: 10.1016/j.jnha.2024.100184
13 Insights on
- Increased Insulin-like Growth Factor-1 Level
- High evidence
- Clinical
significantly increased insulin-like growth factor-1
Effect
Beneficial
Effect size
Small
Significant
Yes
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 Insulin-like Growth Factor-1 Level
- High evidence
- Rigorous Journal
- Adults
no change in IGF-1 (-6.0 ± 27.7 µg/L, -2.1 ± 27.8 µg/L, CON, PRO, resp., p = 0.920)
Effect
Neutral
Effect size
Small
Significant
No
Dose
24 g

Whey Protein and Increased Insulin-like Growth Factor-1 Level

Independent effects of whey protein and alkali supplementation on muscle health in healthy older adults: factorial randomized controlled trial.

Improving sarcopenia in older adults: a systematic review and meta-analysis of randomized controlled trials of whey protein supplementation with or without resistance training.

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