Popular over-the-counter sports rubs may have little real effect on aching muscles and painful joints, a research review suggests.
The review looked at 16 clinical trials investigating topical remedies containing salicylates, a group of compounds, including aspirin, used to ease aches, inflammation and fever.
Many familiar sports rubs, like Aspercreme, Ben Gay and Icy Hot, contain one or more salicylates, often in combination with other active ingredients like menthol.
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"The point is, you go to any pharmacy in the U.S. and find tons of these things, but they don't work," Andrew Moore, a biochemist at Oxford University in the UK and the senior researcher on the review, said in a written statement.
"I wouldn't waste the money," he advised. "You might as well rub your skin with a bit of spit."
Moore and his colleagues base that conclusion on seven studies including nearly 700 people with acute sports injuries, like sprains and strained muscles, and nine studies of 579 people in chronic pain — from arthritis or old sports injuries, for instance.
When it came to acute injuries, study patients were more likely to report pain relief when they were given a sports rub rather than a placebo (a rub containing no active ingredient). But that advantage disappeared when Moore's team looked only at the higher-quality trials.
The remedies fared better in trials of treating chronic pain. Across six studies, 45 percent of participants using the rubs saw their pain decrease by half within two weeks, compared with 28 percent of those on a placebo.
But in general, the studies were small and often had shortcomings in how they were conducted, Moore and his colleagues report in the Cochrane Database of Systematic Reviews, a part of the Cochrane Library.
"The smaller, older studies tend to show an effect while the larger, better, recent trials show no effect at all," Moore said.
Overall, he and his colleagues write, salicylate rubs "compare poorly" with topical nonsteroidal anti-inflammatory drugs (NSAIDs). Such preparations containing ibuprofen or diclofenac (sold as the prescription drug Voltaren gel), for example.
Those products, as well as rubs containing the hot-pepper compound capsaicin, may be better bets for pain relief, according to Moore.
Moore and one of his co-researchers on the review have consulted for various pharmaceutical companies and received fees from them for lectures related to painkillers.
SOURCE: Cochrane Database of Systematic Reviews, online July 8, 2009.