Harvard Health Ad Watch: Aches, pains, and muscle cramps — do well-advertised remedies actually work?

A woman applies a cream to her sore joints and says it's changed her life. Two sports heroes sing the praises of an over-the-counter cream for their aches and pains. A celebrity physician claims that spray-on foam can end your daily suffering.

You've probably seen testimonials like these in over-the-counter pain remedy ads. But is there solid evidence to back up such claims? Let's focus on three products with catchy names and marketing claims in heavy rotation on TV.

• Blue-Emu: Marketed for muscle, joint, or back pain. "… Get back in the game without smelling like a locker room. You can feel 100% confident in using our products to help soothe tired muscles and joints."
• Australian Dream: Marketed for joint or back pain. "Arthritis sufferers and long-time athletes alike rely on our joint pain relief cream for guaranteed comfort. Applied directly to the painful area, this natural blend of ingredients works fast and effectively."
• Theraworx: Marketed for sore muscles, muscle cramps, or joint pain. "Clinically proven to stop muscle cramps before they start.""Provides fast-acting relief of muscle cramps and spasms, as well as post-cramp soreness — most people get relief within minutes!"

What are these seemingly miraculous treatments?

Each is applied directly to skin (topically). Theraworx is a foam; the others come as creams or sprays. According to their manufacturers, here's the ingredient list:

• Blue-Emu: An "original" version has more than 20 ingredients, including glucosamine, aloe vera, and emu oil — but no active ingredient is listed! For Blue-Emu Maximum Arthritis Pain Relief and Blue-Emu Ultra with Hemp Seed Oil, the active ingredient is trolamine salicylate, a close relative of aspirin. Blue-Emu Lidocaine Dry Patch lists lidocaine as the active ingredient; it's similar to the numbing medication novocaine.
• Australian Dream: Emu oil is listed here, too, but the active ingredient is histamine hydrochloride, a topical pain reliever. According to its makers, that ingredient temporarily increases the size of your blood vessels for greater circulation, which "safely and effectively reduces pain in the joint or muscle." (By the way, this product is made in Kentucky, not Australia.)
• Theraworx Relief for Joint Discomfort and Inflammation lists olibanum, an oil from boswellia trees (also called frankincense oil), as its the active ingredient. Twenty other ingredients, including calcium, aloe, and grapefruit extract, are also listed. You'll need to wear a compression sleeve over the sore joint after applying the product.
• Theraworx Relief for Muscle Cramps and Spasms has magnesium sulfate as its active ingredient. While magnesium deficiency can cause muscle cramps, most nonpregnant people given oral magnesium supplements do not benefit. And, no evidence suggests most people with common muscle cramps, such as nighttime muscle cramps, have a magnesium deficiency, or that applying the mineral to skin counters a problem in the muscles.

Do they deliver on their promises?

That depends on how you measure success: by customer ratings, web site reviews, or results of studies in people with symptoms like yours?

While studies of rodents or lab experiments are available, none of the manufacturers' ads or websites provide adequate details about studies demonstrating that their products work on humans.

For example:

• Theraworks Relief for Muscle Cramps and Spasms: Two studies mentioned in an ad show improvement in muscle cramps and spasms in 60% of 84 participants. But it's not possible to track down the actual studies or interpret their results. How long did it take for treatment to work? Does it prevent cramps — or just treat them? How long did the study last? Was Theraworx compared with placebo? No idea! (Healthcare professionals can get more information, but only upon request — and only if they provide personal information and a medical license number.)
  
  A two-week study of 50 paid volunteers noted modest improvement in leg cramps, sleep, quality of life, and depression for those using Theraworx Relief. But it was funded by the product makers, and wasn't published in a mainstream or well-respected medical journal.
• Blue-Emu: The active ingredient, trolamine salicylate, has been studied in small, short-term trials, such as this one from 1982 and this one from 1994. Results were mixed at best and don't support their ads' claims.
• Australian Dream: While not FDA-approved, its marketing says it "contains an FDA-approved ingredient." Indeed, histamine dihydrochloride is a topical pain reliever approved decades ago, despite little research showing it actually relieves pain. Their ads and website provide no human studies of the product to treat joint or back pain. It's not even clear why topical histamine would ease pain. Dilation of blood vessels mentioned in the ads isn't known to provide relief for joint or muscle pain. In fact, one of the more effective pain treatments — applying ice — constricts blood vessels.

And what about the emu oil? Both Blue-Emu and Australian Dream contain it. Some studies have investigated it for burn wound healing in mice and to reduce inflammation in lab experiments. But no convincing data suggest it's an effective pain reliever in humans.

What does the FDA say about these products?

The FDA doesn't directly evaluate the safety and effectiveness of products like these, but it can encourage or require a recall if a product is deemed unsafe. The Federal Trade Commission oversees advertising of over-the-counter therapies like these. Both agencies may be unable to keep up with the sheer volume of products on the market.

The bottom line

Usually, the makers of well-studied products with proven benefits are quite willing to share results of studies demonstrating effectiveness. The fact that none of these product makers do is reason for skepticism.

If you're already using Blue-Emu, Australian Dream, or Theraworx, and it's clearly working well for you, that's great! But there seems to be little evidence that would predict this result.

And if you're considering trying one of these products for the first time, you might think twice. The ads may be convincing, but, in my view, the evidence is not.

Follow me on Twitter @RobShmerling