The synthetic formula of ademetionine was discovered in Italy in 1953 and was researched over the following decades. In the 1970s, Italian researchers investigating its properties as a treatment for schizophrenia discovered that it also had antidepressant properties.

Ademetionine became a useful treatment during the 1990s, when scientists found a way to stabilize it for research purposes. After that technological development, ademetionine could be sold as a medical supplement.

SAMe has been used to treat depression, osteoarthritis, schizophrenia, liver disease, peripheral neuropathy, and other illnesses. As of February 2008, considerable research had been conducted on the use of ademetionine for treating osteoarthritis.

Numerous studies indicated that people diagnosed with osteoarthritis experienced less pain while taking ademetionine. SAMe appeared as effective as non-steroidal anti-inflammatory drugs (NSAIDs) and produced fewer side effects, according to organizations, including the Mayo Clinic.

However, additional research was needed to verify the findings from those studies. In addition, long-term effects of SAMe use were not known in 2008. SAMe has been studied for decades, but research as of 2008 was rated as inconclusive because of factors such as the small number of participants in studies and the absence of a placebo group in some studies.

For example, BMC Psychiatry in 2004 described an eightweek American study of 20 people diagnosed with HIV/AIDS and major depressive disorder. The people took ademetionine and a ‘‘rapid effect’’ was observed after the first week. ‘‘Progressive decreases in depression symptom rating scores’’ were noted during the subsequent weeks of the study.

Ademetionine may be useful in treating fibromyalgia, which is characterized by persistent muscle pain and depression. However, some research involved injections of SAMe. While those studies indicated ademetionine was effective, the body reacts differently to injections than it does to remedies taken orally.

Ademetionine has been suggested for the treatment of conditions, including pain relief, migraine, Alzheimer’s disease, Parkinson’s disease, liver function, and peripheral neuropathy. The supplement had not been fully researched as of February 2008 in terms of safety and effectiveness for these and other conditions.

Scientifically accepted testing of a large human population should provide answers and clear up inconsistencies in earlier studies. For example, some studies indicated that SAMe would not interfere with the effectiveness of levodopa, the drug most often prescribed for Parkinson’s disease. There were no long-term studies on the possible interactions between levodopa and ademetionine.