This dietary supplement, which is short for S-adenosylmethionine, helps regulate some hormones and the neurochemicals that are important to mood: serotonin, melatonin, dopamine, and adrenaline, Dr. Weil says. In Europe, where it is a prescription drug, SAM-e (pronounced "Sammy") is widely used to treat depression. Compared to antidepressant drugs, SAM-e works quickly, and patients often feel the effects within a week. But it's pricey and doesn't work for everyone, he notes. If you want to try SAM-e, take 1,600 milligrams of the butanedisulfonate form daily on an empty stomach. Because SAM-e may increase blood levels of homocysteine, a significant risk factor for cardiovascular disease, this supplement should be taken with folic acid and vitamins B6 and B12 to keep homocysteine levels down.