Background and aim of the review

Muscle soreness typically occurs after intense or unaccustomed exercise. It peaks between 24 and 72 hours after the initial bout of exercise. Many people take antioxidant supplements such as vitamin C and/or E or antioxidant-enriched foods such as tart cherry or pomegranate juice before and after exercise in the belief that these will prevent or reduce muscle soreness after exercise.

Results of the search

We searched medical databases up to February 2017 for studies that compared antioxidant supplementation with a control intervention such as a placebo (a dummy pill or drink that had no antioxidant) or no treatment. We found 50 studies, all of which compared antioxidant supplementation with a placebo. These reported results for a total of 1089 participants. Of these, nearly 9 out of 10 were male. The age range for participants was between 16 and 55 years and their training status varied from sedentary to moderately trained. The studies were very varied such as in the type and dosage of the antioxidant supplement and the type of exercises used to cause muscle soreness. All studies used an antioxidant dosage higher than the recommended daily amount.

Key results

There is evidence that high dose antioxidant supplementation may slightly reduce muscle soreness at up to 6 hours and at 24, 48 and 72 hours follow-up but not at 96 hours. However, these reductions were so small that they were unlikely to make any difference. None of the trials reported on outcomes related to subjective recovery, such as return to previous activities without signs or symptoms.

Only nine studies reported on adverse effects and only two found adverse effects. All six participants in the antioxidant group of one trial had diarrhoea and four of these also had mild indigestion; these are well-known side effects of the particular antioxidant used in this study. One of 26 participants in a second trial had mild gastrointestinal distress.

Quality of the evidence

We considered the evidence for muscle soreness to be ‘moderate’ or ‘low’ quality. This was mainly because the majority of studies had aspects that could have affected the reliability of their results and in some cases because of variation in the results of the studies. This means there is some uncertainty about the findings and further research may provide evidence that could change our conclusions.

Authors’ conclusions

Antioxidant supplementation does not appear to reduce muscle soreness early on or at one, two, three or four days after exercise.