Like all good spoofs, the ad, which promotes an arthritis cream called Thera-Gesic, draws from reality. Over the centuries, people have been willing to rub all sorts of things onto their sore joints. Today, arthritis sufferers can choose from a wide range of over-the-counter creams with different approaches to relief. Bengay Ultra Strength contains 30 percent methyl salicylate, an aspirin-like compound, along with the cooling ingredients menthol and camphor. A 2-ounce tube costs about $5. Thera-Gesic contains 15 percent methyl salicylate and a little menthol. Users are instructed to spread a thin layer of the cream over sore spots no more than three or four times a day. According to the label, they can apply one or two extra layers at a time for more serious relief. A 3-ounce tube costs about $5. Zostrix contains .075 percent capsaicin, a compound that gives chili peppers their heat. According to the directions, users should apply the product three to four times a day, every day. The Web site cautions that users might feel a burning sensation at first, and that it might take a week or two to notice any results. A 2-ounce tube costs about $16.
The bottom line Rubbing any sort of cream or lotion into a sore joint can feel good, says Dr. Roy Altman, a professor emeritus of rheumatology at UCLA. "There's a sensation that it's doing something, and people believe in it," he says.
Still, there's no good evidence that over-the-counter creams offer real relief for arthritis, Altman says. As Altman noted in a March 2009 issue of the journal Postgraduate Medicine, the only placebo-controlled study of a salicylate cream applied directly to arthritic joints found that the cream worked no better than the placebo.
Altman was the lead author of a 1994 study that found that a .025 percent capsaicin cream worked better than a placebo cream, but the relief was minor and didn't show up until four weeks of treatment. Because there's so little evidence behind salicylate creams, Altman doesn't recommend them, but he also doesn't tell patients who are already trying the products to stop. Both salicylates and capsaicin supposedly relieve pain by irritating nerve endings in the skin. In theory, the nerves become too distracted to notice arthritis pain. In reality, Altman says, the effect is usually either too fleeting or too mild to notice.