Wearing a copper bracelet won't help relieve arthritis pain, British researchers say.

The first randomized, placebo-controlled trial testing copper bracelets and magnetic wrist straps to manage pain in osteoarthritis, the most common form of the condition, suggest any perceived benefits may be a psychological placebo effect.

"People tend to buy them when they are in a lot of pain, then when the pain eases off over time they attribute this to the device," said Stewart Richmond of the department of health sciences at the University of York, in the U.K., who led the study.

'Our results indicate that magnetic and copper bracelets are generally ineffective for managing pain, stiffness and physical function in osteoarthritis.'— Study's authors

"However, our findings suggest that such devices have no real advantage over placebo wrist straps that are not magnetic and do not contain copper," he added in a release.

Using the devices is generally harmless, but people with osteoarthritis should be cautious about spending a lot of money on magnet therapy, Richmond advised.

The study, in this week's online issue of the journal Complementary Therapies in Medicine.

The trial included 45 people aged 50 or over who were all diagnosed with osteoarthritis.

Each participant wore four devices in a random order over 16 weeks:

• Two were wrist straps with differing levels of magnetism.
• A demagnetized wrist strap
• A copper bracelet.

Neither the researchers nor the participants knew which device was being worn.

"Our results indicate that magnetic and copper bracelets are generally ineffective for managing pain, stiffness and physical function in osteoarthritis," the study's authors concluded.

No meaningful differences were found between the devices in terms of effects on pain, stiffness and physical function.

The annual worldwide sales of therapeutic devices that include permanent magnets is worth up to $4 billion US, the researchers said.

Osteoarthritis is caused by the wearing down of cartilage in the joints of the body, which can cause pain, stiffness and swelling.

Osteoarthritis affects an estimated 3,000,000 or one in 10 Canadians, according to the Arthritis Society.

The Wolds Primary Care Research Network funded the trial.