SAMe (S-adenosyl-methionine) is a natural metabolite of the amino acid methionine. SAMe is a “methyl-donor”, meaning it is a co-factor in a number of critical biochemical reactions in the body including the manufacture of important brain compounds like neurotransmitters.
SAMe supplements are available as tablets and capsules.
For pets (and humans), SAMe is used to treat for anxiety disorders and depression.
SAMe might also have pain reduction properties. A 2004 study compared the effectiveness of SAMe to the Nsaid drug celecoxib for pain control in people with osteoarthritis of the knee. The study concluded, "SAMe has a slower onset of action but is as effective as celecoxib in the management of symptoms of knee osteoarthritis."
In the body, L-methionine (methionine) converts to SAMe (S-adenosyl-methionine), which is a popular supplement for treating mood and anxiety disorders. However, the ability of SAMe to penetrate the blood-brain barrier is limited, and a 2005 study found that use of L-methionine (methionine) "caused larger increases in brain SAMe at lower doses."