“I think we were surprised that in many cases there was so little evidence for effectiveness for therapies which were commonly used,” says Dr. Macfarlane. “There was a lack of evidence for [the use of] collagen, homeopathy, vitamin supplements and willow bark” for RA and OA, he adds.

Despite the shortage of supporting evidence, many people believe supplements are effective, says pharmacist Donald Miller, professor and chair of pharmacy practice at North Dakota State University in Fargo.

In fact, half of adult Americans use supplements, including multivitamins, minerals and herbs, according to the Centers for Disease Control and Prevention (CDC). And according to Consumer Reports, U.S. consumer spending in the steadily growing industry accounted for almost $27 billion in 2009.  

People with arthritis and musculoskeletal conditions often try alternative medicines in an effort to manage their pain, the researchers say.

Miller agrees. “There’s this feeling that there’s got to be a magic bullet, that there’s something better out there,” he says. “It’s difficult to live with pain all the time.”

Researchers also issued safety scores for the compounds, using a traffic-light system. Those that scored “green” were found to have only minor and infrequent side effects, an “amber” rating was issued to compounds having commonly reported and in some cases more serious side effects, and those that received a “red” rating have serious side effects. None of the supplements evaluated were issued a “red,” or unsafe, rating. But six supplements were given an “amber” rating, including flaxseed oil (for RA).

“If people are taking [supplements] with no side effects, they can continue,” Miller says, given the report’s safety findings. “But if they are considering taking them, they should think carefully about it, and talk to their doctor or pharmacist about better established alternatives.”

The U.S. Food and Drug Administration does not regulate supplements as it does drugs. Therefore, makers of these alternative products do not need to prove safety or efficacy, leaving the buyer to make decisions on his or her own.