Question & Answer

Does consuming protein after a work-out in the gym (cardio or resistance training)helping to build muscle?

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The Evidence

  • One high-quality study found that consuming protein with or without added carbohydrates can help increase muscle mass and strength among people who are doing exercise that combines resistance and endurance training.
  • Other research shows that multi-ingredient protein supplements help to increase the lower and upper body muscle mass and strength as a result of resistance training.
  • A study reported that the protein supplementation is effective in improving lean body mass (LBM) in adults and older adults, but not handgrip strength and leg press strength.
  • The effect of protein or essential amino acid supplementation during prolonged resistance exercise training in older adults is weak, inconsistent or not significant.
  • In addition, one study suggested there is no difference between the effects of soy protein versus animal protein supplements on gains in muscle mass and strength in response to resistance exercise. They both increase LBM and strength.

Guidelines and recommendations

  • National Institutes of Health recommends that athletes consume high-quality protein after exercise and then every 3 to 5 hours to maximise muscle adaptations to training.

Things to Remember

  • We can rarely be 100% certain about the effects of treatments. Please beware when someone suggests that it is certain that a treatment works or is safe.
  • Remember to ask if the treatment comparisons in a study happened under ideal circumstances, rather than under real life circumstances. We need to know how a treatment works in real life.


  • Lead Researcher: Dr. Petek Eylul Taneri, HRB TMRN, College of Medicine, Nursing and Health Sciences, University of Galway.
  • Reviewed by: Dr. Paula Byrne, Senior post-doctoral researcher, iHealthFacts, Evidence Synthesis Ireland and Cochrane Ireland, College of Medicine, Nursing and Health Sciences, University of Galway.
  • Topic advisor: Dr. Kevin Cradock, Lecturer, Department of Health and Nutrition Sciences, Atlantic Technological University, Sligo.
  • Public and Patient advisor: Deirdre Mac Loughlin, Public and Patient Involvement in research (PPI) advisor, PPI Ignite, University of Galway
  • Journalist Advisor: Dr. Claire O’Connell, PhD in cell biology, Masters in Science Communication. Contributor to The Irish Times, writing about health, science and innovation.

Conflict of Interest Statement: The authors have no financial or other conflicts of interest for this health claim summary.