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Wp9.0
Whey Protein Research
Likely helpsHigh safety
108 peer-reviewed studies
What the evidence says
Likely helps
Whey Protein appears to help in 19 of 22 studies with measurable effects — the evidence leans clearly favourable.
Most evidence is from high-quality meta-analyses and randomised trials published 2006–2026 with a typical study size of 45 participants.
Based on 108 studies · 24 meta-analyses · 71 RCTs · 42,808 total participants
Confidence
High
What the studies found
19helped3unclear· 86 more without graded effect data
By outcome
Lean body mass & muscle growthEnhanced muscle protein synthesis · 2-4 weeks
Likely helps95 studies
Muscle strength & powerEnhanced muscle protein synthesis · 2-4 weeks
Likely helps39 studies
Therapeutic & clinical
Likely helps26 studies
RecoveryFaster muscle recovery post-workout · Immediate to 24 hours
Mostly mechanism / observational19 studies
Weight management
Mostly mechanism / observational17 studies
Glucose & metabolic
Likely helps10 studies
Safety profile
Likely helps9 studies
Endurance & exercise performanceProtein supports muscle repair for endurance training recovery · 2-4 weeks · Supports recovery and adaptation to training · Ongoing
Mostly mechanism / observational7 studies
Inflammation
Mostly mechanism / observational6 studies
Heart & blood pressure
Mostly mechanism / observational5 studies
Women's health
Mostly mechanism / observational4 studies
Anxiety & stress
Mostly mechanism / observational3 studies
Bone healthSupports bone mineral density and skeletal strength · 8-12 weeks
Too few graded studies2 studies
Muscle cramps & function
Too few graded studies2 studies
Liver health
Too few graded studies2 studies
Cholesterol & lipids
Too few graded studies1 study
Cognitive function
Too few graded studies1 study
Depression & mood
Too few graded studies1 study
Sleep & insomnia
Too few graded studies1 study
Digestive health
Too few graded studies1 study
By the numbers
Pulled from 43 studies with measurable effects
Likely real effects
76%
across studies
People studied
43k
typical study: 45 people
Strongest designs
95
24 pooled, 71 randomised
Showed benefit
86%
19/22 studies
How long studies ran
Under a week
2
1–4 weeks
4
1–3 months
4
3+ months
7
Populations Studied
Older adults5
Older adults with sarcopenia3
Sarcopenic elderly2
Persons with type 2 diabetes mellitus1
Active research area
91 studies in the last 5 years · Latest meta-analysis: 2024
200620162026
1Meta-AnalysisCited 30×n=5,272 · very large study2024
Our findings suggest whey protein yields the optimal supplements to counter sarcopenia in older individuals undergoing RT.
Liao CD et al. · Nutrients (2024)
Treatment effects for main outcomes were expressed as standard mean difference (SMD) with 95% confidence interval (CI).
Meta-regression analyses were performed to identify any relevant moderator of the treatment efficacy and results were expressed as β with 95% credible interval (CrI).
We finally included 78 RCTs (5272 participants) for analyses.
3Lower body strengthMeta-AnalysisCited 6×n=2,105 · very large study2024
The present meta-analysis indicates that WPS, when combined with resistance training (RT), can enhance lower body strength but does not seem to have a significant beneficial effect on handgrip strength, physical performance, or body composition.
Al-Rawhani AH et al. · Clinical nutrition (Edinburgh, Scotland) (2024)
Noticeable benefit
← WorseNo effectBetter →
However, ASM significantly improved after WPS consumption but with high heterogeneity (n = 2, SMD: 0.39; 95%CI: 0.28, 0.51; I2 = 69%).
In interventions incorporating RE, statistically significant positive effects of WPS on lower body strength were observed (n = 11, SMD: 0.25; 95%CI: 0.05, 0.45; I2 = 0%).
The present meta-analysis indicates that WPS, when combined with resistance training (RT), can enhance lower body strength but does not seem to have a significant beneficial effect on handgrip strength, physical performance, or body composition.
In addition, combining a physical exercise program with whey protein, leucine, and vitamin D supplementation can improve muscle strength and function.
Chang MC et al. · Nutrients (2023)
However, appendicular muscle mass significantly improved in the experimental group compared to the control group.
With the use of a concomitant physical exercise program, handgrip strength and SPPB scores in the experimental group significantly improved when compared to the control group.
In contrast, when physical exercise was not combined, there was no significant improvement in the handgrip strength and SPPB scores of patients with sarcopenia.
10Physical functionMeta-AnalysisCited 59×n=33 · small study2023
Standardized mean differences (SMDs) were calculated for LM, muscle strength, and physical function data.
Nasimi N et al. · Advances in nutrition (Bethesda, Md.) (2023)
Large benefit
← WorseNo effectBetter →
Standardized mean differences (SMDs) were calculated for LM, muscle strength, and physical function data.
The analysis showed that whey protein supplementation had no effect on LM and muscle strength; nevertheless, a significant improvement was found in physical function (SMD = 0.561; 95% confidence interval [CIs]: 0.256, 0.865, n = 33), particularly gait speed (GS).
On the contrary, whey protein supplementation significantly improved LM (SMD = 0.982; 95% CI: 0.228, 1.736; n = 11), appendicular lean mass and physical function (SMD = 1.211; 95% CI: 0.588, 1.834; n = 16), and GS in sarcopenic/frail older adults.
11IL-6 reduction with whey proteinMeta-AnalysisCited 45×2023
These data support that whey and soy protein supplementation elicit anti-inflammatory effects by reducing circulating IL-6 and TNF-α levels, respectively.
Prokopidis K et al. · The British journal of nutrition (2023)
Noticeable benefit
← WorseNo effectBetter →
A significant reduction of circulating IL-6 levels following whey protein [Mean Difference (MD): -0·79, 95 % CI: -1·15, -0·42, I2 = 96 %] and TNF-α levels following soy protein supplementation (MD: -0·16, 95 % CI: -0·26, -0·05, I2 = 68 %) was observed.
The addition of soy isoflavones exerted a further decline in circulating TNF-α levels (MD: -0·20, 95 % CI: -0·31, -0·08, I2 = 34 %).
According to subgroup analysis, whey protein led to a statistically significant decrease in circulating IL-6 levels in individuals with sarcopenia and pre-frailty (MD: -0·98, 95 % CI: -1·56, -0·39, I2 = 0 %).
Our study supports a beneficial role of high-quality protein supplementation to reduce CVD risk factors.
Zhou S et al. · Clinical nutrition (Edinburgh, Scotland) (2024)
Our study supports a beneficial role of high-quality protein supplementation to reduce CVD risk factors.
Further studies are still warranted to investigate the effects of different high-quality proteins on CVD risks in individuals with cardiometabolic disorders.
Postprandial glycemia was significantly lower at 60 minutes (weighted mean difference: -2.67 mmol/L; 95% confidence interval, -3.62 to -1.72 mmol/L) and 120 minutes (-1.59 mmol/L; -2.91 to -0.28 mm...
Chiang SW et al. · Nutrition research (New York, N.Y.) (2022)
Noticeable benefit
← WorseNo effectBetter →
Postprandial glycemia was significantly lower at 60 minutes (weighted mean difference: -2.67 mmol/L; 95% confidence interval, -3.62 to -1.72 mmol/L) and 120 minutes (-1.59 mmol/L; -2.91 to -0.28 mmol/L) in WP group than in placebo group.
Although other results favored the WP group, differences between the groups were not statistically significant.
The present study showed that premeal WP supplementation is beneficial for postprandial glycemia in persons with mild or well-controlled T2DM without substantial adverse effects.
15Adverse effects on healthSystematic ReviewCited 31×2021
Presented data support a need for future studies co-relating the use of different types of whey protein with and without exercise to better see the impact on human physical health.
Vasconcelos QDJS et al. · Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme (2021)
PROSPERO registration no.: CRD42020140466.
Novelty: A systematic review of experimental and randomized studies about the use of whey proteins supplements and its impact on physical health.
Analysis revealed that chronic and without professional guidance use of whey protein supplementation may cause some adverse effects specially on kidney and liver function.
17Biceps curl strengthMeta-AnalysisCited 16×n=14 · very small study2022
Without RT, WP has no significant benefit on muscle strength or lean mass.
Kuo YY et al. · Nutrients (2022)
Large benefit
← WorseNo effectBetter →
Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were used to estimate the effect of WP.
In the RT subgroup, WP supplementation had a significant positive effect on biceps curl strength (BC) (SMD: 0.6805, 95% CI: 0.176, 1.185, I2: 0%), and lower limb lean-mass (LLLM) (SMD: 1.103, 95% CI: 0.632, 1.574, I2: 14%).
In the subgroup without RT, a significant negative effect on PI (SMD: -0.4225, 95% CI: -0.774, -0.071, I2: 47%) was observed, while no significant effect on muscle strength or lean mass was revealed.
Due to several and important limitations, more detailed analyses are required regarding FFM gain.
A Castro LH et al. · Nutrients (2019)
Borderline
Random effect meta-analyses were performed from the final and initial body composition values of 246 healthy athletes undergoing 64.5 ± 15.3 days of training in eight randomized clinical trials (RCT) collected systematically from five scientific databases.
There was no significant effect on FFM in any of the scenarios investigated (p > 0.05).
Due to several and important limitations, more detailed analyses are required regarding FFM gain.
Whilst the effects for WP were shown to be consistent over time, these results are limited to 13 RCTs, principally supporting the requirement for further comprehensive research in this area.
Davies RW et al. · Nutrients (2018)
Eight studies, containing 13 randomised control trials (RCTs) were included in this review and meta-analysis, from which individual standardised effect sizes (ESs) were calculated, and a temporal overall ES was determined using a random-effects model.
This systematic review and meta-analysis provides a synthesis of the literature to date, investigating the effect of WP supplementation on the recovery of contractile function in young, healthy adults.
Whilst the effects for WP were shown to be consistent over time, these results are limited to 13 RCTs, principally supporting the requirement for further comprehensive research in this area.
In healthy free-living older adults reporting a protein intake at the current recommended daily allowance, neither increasing protein to 1.5 g/kg/d with WP nor adding a KHCO3 supplement for 24 wk improved measures of muscle power, physical performance, or muscle mass despite achieving higher circulating IGF-1 levels.
Ceglia L et al. · The American journal of clinical nutrition (2026)
In the intention-to-treat sample (n = 128), 47.7% were female, mean ± SD age was 74 ± 6 y, and baseline protein intake was 0.85 ± 0.30 g/kg/d.
Neither WP nor KHCO3 affected muscle power compared with their respective placebo {WP to placebo-WP difference 4.7 watts [95% confidence interval (CI): -21.1,30.5; P = 0.72]; KHCO3 to placebo-KHCO3 difference -13.6 watts [95% CI: -39.6, 12.4; P = 0.30]}.
However, 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); KHCO3 to placebo-KHCO3 difference 7.2 ng/mL (95% CI: 0.4, 13.9; P = 0.04)].