Many different nutritional supplements are sometimes suggested to help with depression or bipolar disorder. Three of them have been studied enough that we can say something about their effectiveness and safety: s-adenosyl methionine (also called SAMe), omega-3 fatty acids (often found in fish oil), and hypericum (also called St. John’s Wort).
SAMe has been studied as a treatment for depression since the 1980s, including blinded studies comparing it to a placebo. There is reasonable evidence that SAMe is effective either alone or in combination with prescribed antidepressants. No specific risks have been identified, and it appears to have fewer side effects than most prescribed antidepressants. While the evidence for SAMe is not as extensive as for prescribed antidepressants (fewer studies involving fewer patients), it is certainly reasonable to consider. SAMe has not been well studied as a treatment for depression in bipolar disorder. It may be effective, but (as with prescribed antidepressants) it could bring on mania or more rapid mood swings.
