Review questions evidence that muscle rub ingredient is effective

By Simon Pitman

- Last updated on GMT

A new scientific review suggests that there is not enough evidence to prove that rubefacients are effective at relieving muscle pain.

Commonly used in over-the-counter gels and creams by sportsmen and athletes to treat muscle injuries and pain, rubefacients are also prescribed to treat more serious medical conditions associated with pain.

Rubefacients act on pain by promoting blood flow in the area where the formulation is topically applied, but the treatment can also lead to skin irritation and reddening of the skin, the review underlined.

This effect is known as a ‘counter irritant’ because it is thought to offset localized pain through local skin irritations.

Deep Heat, best known brand

One of the best known brands on the European market to rely on this ingredient in the formulation is Deep Heat, which is generically known as a rubbing alcohol.

The Cochraine researchers concentrated on reviewing a range of products that used a type of rubefacient known as salicylates, a substance that is also commonly used in topical products used to treat acne.

Deep Heat contains an approximately 13 per cent dose of methyl salicylate.

Need for high quality evidence

“At present, due to a lack of high quality evidence, we can’t say exactly how effective rubefacients are for acute injuries and there are certainly other more effective treatments which could be prescribed for chronic conditions,”​ said researcher Andrew Moore of the Nuffield department of anaesthetics at the University of Oxford.

The review analysed data from 16 trials for acute and chronic pain, which considered a total of 1,276 volunteers.

Although each of the trials were said to be small, the reviewers said that only four of the studies showed that salicylates were proven to perform better than placebos at reducing pain.

No categorical evidence to prove effectiveness

After excluding a number of lower quality studies, the reviewers said that the only reliable results they came across did not provide categorical evidence to suggest that rubefacients were effective in treating pain.

“Larger and higher quality controlled trials of topical rubefacients are needed to establish whether these treatments work,"​ said Moore

"We also need more studies on other rubefacients as we were only able assess the effectiveness of salicylate formulations in this review.”

Related topics Formulation & Science

Related news