An older woman does yoga.

More than 91 million adults in the U.S. may have arthritis, according to a recent estimate—most commonly osteoarthritis, which causes joint damage and pain. If you're one of them, you may have considered alternative treatments for arthritis.

About 40 percent of those with arthritis have tried a complementary or an alternative therapy such as acupuncture or yoga, according to the Centers for Disease Control and Prevention (CDC).

More on Arthritis

Are any of them useful for arthritis? "These are not game-changers," says Richard Panush, M.D., a professor at the Keck School of Medicine at the University of Southern California. "Some at best may have small effects in some circumstances for some people."

Here's what the research shows.

4 Alternative Treatments That May Help

Massage. A review of studies published in Mayo Clinic Proceedings suggests that massage therapy can help ease the pain and stiffness of knee osteoarthritis. Researchers in one study recommended a weekly 60-minute session with a licensed massage therapist. (You can find one at the American Massage Therapy Association website.)

Tai chi. The Chinese exercise, with its slow, rhythmic movements, was found in a 2015 review of 54 studies to cut arthritis pain slightly. But it was less effective than aerobic and strength exercises. (Get more info at the American Tai Chi and Qigong Association website.)

Yoga. A review of 17 studies published in the journal Musculoskeletal Care found that yoga reduced osteoarthritis pain. But our experts recommend avoiding Bikram (hot yoga) if you have joint problems. The heat may make you feel as if you can stretch more than you should, which can further damage joints.

Acupuncture. Research suggests that this traditional Chinese therapy, which involves inserting thin needles into the body at particular spots, reduces osteoarthritis discomfort for some people. One theory is that it may trigger the release of pain-suppressing hormones called endorphins. Or it may simply provide a placebo effect, helping you feel better without a medical reason. If you try it, make sure you're treated by a credentialed practitioner. (Find one at the website of the National Certification Commission for Acupuncture and Oriental Medicine.)

3 Therapies to Avoid

Chiropractic manipulation. Some research suggests that the "realigning" of the spine by a chiropractor can ease some general back and neck pain. But a 2012 review, published in the journal Rheumatology, found no good evidence that the therapy effectively reduces osteoarthritis pain.

Dietary supplements. Some people use supplements such as glucosamine and chondroitin (often together) or fish oil for joint pain. So far, studies have shown that glucosamine and chondroitin are no more effective than a placebo. Some research suggests that high doses of fish oil may help ease the joint ache of rheumatoid arthritis, an autoimmune condition. But its effect on osteoarthritis is unclear. Plus, fish-oil supplements can cause side effects such as diarrhea and stomach pain. And dietary supplements aren't well-regulated by the Food and Drug Administration, so you can't be sure the one you take contains what's on the label.

Homeopathy. The principle behind homeopathy is that certain highly diluted substances can cure illness. For instance, rhus toxicodendron—made from poison ivy—is touted as an osteoarthritis treatment. But there's no good evidence to support using homeopathic remedies for arthritis or any other condition, according to Marvin M. Lipman, M.D., professor emeritus of clinical medicine at New York Medical College in Valhalla, N.Y., and former chief medical adviser for Consumer Reports.

3 Smart Strategies

Before you use any alternative treatments for arthritis, Lipman recommends that you try addressing factors that are known to contribute to pain and musculoskeletal complaints.

Lose weight if you need to. Excess weight puts added pressure on ankles, hips, and knees, which can increase arthritis severity and pain.

Get the right kind of exercise. Activities that strengthen muscles, improve your range of motion, and boost your cardiovascular activity can help. In addition to tai chi and possibly yoga, consider a regular walking or swimming program. Get more information on arthritis-friendly exercise here.

Talk with your doctor. If you decide to try an alternative therapy, let your doctor know beforehand. He or she may be able to refer you to a trustworthy practitioner. Your doctor can also tell you about any potential dangers or whether the therapy might interact with your regular medication.

Editor's Note: This article also appeared in the February 2017 issue of Consumer Reports on Health.