Supplements are often touted as a miracle cure-all for everything from your skin to your sex drive, but a new study has found that, rather than helping your health, the supplement ‘SAMe’ could actually be harming it.

An international group of biologists has warned against the use of SAMe, calling it toxic and unsafe. The team – from Manchester and Kyoto universities – reported last week that they had discovered the supplement can break down inside the body, creating “toxic” substances which cause a wide range of medical problems, including kidney and liver damage. 

“This discovery came out of the blue,” Jean-Michel Fustin, of Manchester University, said last week. “When we gave the supplement to mice we expected they would become healthier. But instead we found the opposite. We found that when SAMe breaks down in the body, it produces very toxic molecules, including adenine which causes gout, kidney disease and liver disease.”

SAMe, which is short for S-adenosylmethionine, is not sold at pharmacies in the UK but is promoted online as a supplement to aid a range of health conditions including liver disease, osteoarthritis and depression. S-adenosylmethionine is a naturally-occurring compound found in almost every tissue and fluid in the body, and it plays a role in the immune system, maintains cell membranes, and helps produce and break down brain chemicals, such as serotonin, melatonin, and dopamine.

Although it is sold as a prescription drug in countries including Italy, Germany, Russia and India, previous studies on SAMe supplements reported potential promise but the need for further investigation. Evidence on whether SAMe could mitigate the pain of osteoarthritis was deemed inconclusive due to clinical trials being too small. Meanwhile, a 2016 review concluded that there was an absence of high-quality evidence for its use as a treatment for depression.

“The health benefits that manufacturers claim are questionable to say the very least. And because it’s unclear what dose is safe, there is a good chance that a safe dose will be exceeded – if one exists at all,” Fustin said of the supplement. “We should trust the amount of SAM our own body produces unless there are clear clinical signs of deficiencies.”

The study was funded by the Medical Research Council and the Japanese Society for the Promotion of Science. Although carried out on mice, Fustin and his colleagues have said the results were relevant for humans. “We have not yet tested the supplement on men and women but we have added it to human cells in laboratory cultures and have found it had the same effect as it had on mice,” Fustin explained.

The team has warned people to stop using the supplement until more research is done. “I would advise the public to steer clear of SAMe, at the very least  until we understand more about its effect on human health.”