Ask An Expert: Supplement for Serotonin

Content provided by the Faculty of the Harvard Medical School

Ask An Expert: Supplement for Serotonin

Question:

Is 5-HTP safe? I've been reading a book that discusses how low levels of serotonin can affect mood. The book suggests trying 5-HTP. I'd like to know more about this from a medical perspective before I try it.

Answer:

Mood researchers have been interested in 5-HTP (5-hydroxy-L-tryptophan) for more than 40 years.

5-HTP is converted to serotonin in the body. Serotonin, like other "neurotransmitters," carries signals between nerve cells in the brain.

So-called serotonin circuits participate in regulating mood. Many well-known antidepressant medicines work by boosting the serotonin concentrations in the gaps between nerve cells.

So it's not surprising that people think of depression as a "chemical imbalance," or that low serotonin concentrations cause depression. It's tempting to imagine topping off our serotonin to improve our mood, like putting oil in a car engine.

But the reality is much more complicated. No one really knows how the brain produces mood. In fact, the more we learn about the brain, the more tangled (and interesting) the science becomes: numerous chemicals, cells, circuits and even brain regions working together, reacting to the environment.

Still, serotonin-specific antidepressants work, so why not 5-HTP?

Most of research on 5-HTP as an antidepressant was done in the 1970s and 1980s, before drugs like Prozac were available. The studies were not of very high quality. Some showed that 5-HTP was better than a placebo at improving mood, but the information was not conclusive.

Side effects of 5-HTP are nausea, vomiting, diarrhea, headache, sleeplessness, and palpitations. Theoretically, any drug that affects serotonin can cause a "serotonin syndrome," a serious condition that includes fever, high blood pressure, dizziness and disorientation.

It is hard to recommend 5-HTP as a treatment for depression.

Other standard treatments for depression (medications as well as psychotherapy) have been much more carefully studied. The specific benefits and risks for these are well known. The doses are well-worked out and, for your safety, the treatments are carefully regulated. So if you are having problems with your mood, one of these better-known treatments may be a better bet.

Michael Craig Miller, M.D., is editor-in-chief of the Harvard Mental Health Letter and an assistant professor of psychiatry at Harvard Medical School. Dr. Miller has an active clinical practice and has been on staff at Beth Israel Deaconess Medical Center for more than 25 years.

Last updated:	July 23, 2007