Whey protein and muscle recovery after resistance training
What it found
In young, healthy adults, whey protein had small to medium benefits for restoring muscle function in the hours and days after resistance training.
The evidence comes from 13 randomised controlled trials.
What they found
Studies in people
Muscle function recovery
Whey protein produced small to medium overall benefits for restoring muscle function from less than 24 hours up to 96 hours after resistance training, compared with control. The effect sizes ranged from 0.4 to 0.7.
Mixed study results
Four of the eight included studies reported overall beneficial effects for whey protein, while the other four found no overall effect. Only one negative effect was reported out of 44 time-point comparisons.
Muscle damage markers
Whey protein did not reduce creatine kinase activity or muscle soreness at any time point. Creatine kinase is an indirect marker of exercise-induced muscle damage.
Trained versus untrained
Similar small to medium effects were seen whether subjects were untrained or trained. Untrained subjects had an effect size of 0.5, and trained subjects 0.4.
Sex bias in research
Only one study tested young, healthy women in a mixed-sex sample. The remaining seven studies tested young, healthy men, who made up about 92% of subjects.
Other findings
Dosing and timing
Whey protein was given as a single bolus, with a median dose of 25 g (range 20 g to about 120 g). Most trials gave it after exercise, some before, and some both before and after.
What the authors conclude
“Authors caution against interpreting the overall temporal ES reported in this study as definitive evidence.”
Also in their conclusions
- They say a small to medium effect was observed for whey protein accelerating the recovery of muscle function after resistance training.
- They caution against interpreting the overall effect as definitive evidence.
- They call for further high-quality research, especially with trained subjects, performance-based measures, and repeated bouts.
How it was done
Strenuous resistance training can damage working muscle and reduce its ability to produce force for hours or days. Whey protein is known to boost muscle protein synthesis after exercise, so the authors wanted to see whether it helps muscle function recover.
They pooled 8 studies containing 13 randomised controlled trials, with 152 subjects in total. Most subjects were young, healthy men. Muscle function was measured after resistance training, and whey protein was compared with a placebo or control.
What it can’t tell you
- The findings are limited to 8 studies and are considered underpowered for analysing other factors like subject characteristics or exercise mode.
- The studies were biased towards purposefully damaging exercise, which may limit how well the results apply to other types of training.
- Dietary control was absent in most trials, so the influence of other dietary protein is unclear.
Who paid
- Conflicts
- The authors declare no conflict of interest. The sponsors had no role in the design, collection, analysis, interpretation of the data, writing of the manuscript, or in the decision to publish the results.
- Authors work at
- University of Limerick, Ireland
The paper
- Title
- The Effect of Whey Protein Supplementation on the Temporal Recovery of Muscle Function Following Resistance Training: A Systematic Review and Meta-Analysis
- Type
- Systematic review and meta-analysisThe authors follow a set, published method to find every relevant study, then combine the numbers from them into one result.
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Davies RW, Carson BP, Jakeman PM (2018). The Effect of Whey Protein Supplementation on the Temporal Recovery of Muscle Function Following Resistance Training: A Systematic Review and Meta-Analysis. Nutrients. doi:10.3390/nu10020221Free full textPubMed 29462923DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error