Alternative medicines for arthritis don't help, says the UK-based Arthritis Research Campaign says.
The campaign looked at the scientific evidence available for 40 treatments.
Two thirds of treatments for rheumatoid arthritis and a fifth of treatments for osteoarthritis were found to be ineffective by the researchers
In total, 60% of people with arthritis are thought to use some form of complementary medicine.
The researchers looked at compounds taken by the mouth or applied to the skin.
When the researchers examined treatments for rheumatoid arthritis, they found 13 out of 21 complementary medicines were shown to have no or little effect based on the available evidence.
The 13 were: antler velvet powder, blackcurrant seed oil, collagen, eazmov (a herbal mixture), feverfew (herb), flaxseed oil, green-lipped mussels, homeopathy, reumalex herbal mixture, selenium, the Chinese herb tong luo kai bi, vitamins A, C and E, and willow bark.
However, fish body oil was given five out of five in the report, for being effective in reducing joint pain and stiffness.
In addition, six out of 27 treatments for osteoarthritis were shown to have little or no effect based on the available evidence
Capsaicin gel, made from chilli peppers, proved most effective in relieving pain and joint tenderness.
But the effectiveness of glucosamine, a popular supplement used by people with osteoarthritis was again called into question.
For fibromyalgia, which causes widespread pain in muscles and joints, only four products were assessed, none were found to be highly effective with three medicines scoring two out of five, and the fourth just one.
The researchers also examined how safe compounds were.
One - thunder god vine, a traditional Chinese medicine - was given a "red" classification, meaning there were serious safety concerns.
A quarter of the compounds were given an "amber" safety classification, because there were some reported side-effects.
The team said they were unable to evaluate the effectiveness of 36 therapies, including basil, green tea, sarsaparilla and St John's Wort because there was insufficient data.
Professor Gary Macfarlane, from the University of Aberdeen, said while different things worked for different people, "it is useful to also have the scientific evidence available and just as important to know how safe we think they are to use."
Professor Alan Silman, the Arthritis Research Campaign's medical director, added: "We didn't start this saying this was our opportunity to knock complementary medicines.
"The message is not 'don't take them'. The message is 'if you are going to take them, be aware of what the level of evidence is'."
Dr Peter Fisher, clinical director of the Royal London Homeopathic Hospital, said the report focused on tablets and preparations applied to the skin, missing out therapies such as acupuncture and osteopathy.
"I think what really comes across in this report is how sorely under-researched this area is," he said.
Jane Gray, president, of the National Institute of Medical Herbalists added: "This report is a commendable attempt to provide information on self help products for osteo and rheumatoid arthritis."