Supplement To Increase Serotonin

Serotonin is a neurotransmitter that is manufactured by your nerve cells. When released into a synapse, it helps to propagate an electrical impulse from one neuron to the next. Serotonin is also produced by specialized cells that reside in your gut, where it helps to regulate intestinal movement. The platelets in your bloodstream release serotonin at sites of injury to help blood vessels constrict, thereby reducing blood loss. Serotonin is mostly known for its role in mood disorders, such as depression.

Serotonin Synthesis

Serotonin is produced in your brain and gastrointestinal system through a two-step process that first converts L-tryptophan, an amino acid, to a molecule called 5-hydroxy-L-tryptophan, or 5-HTP. 5-HTP is then converted to serotonin. Each of these steps requires the participation of a different enzyme, and vitamin B6 acts as a cofactor in the conversion of 5-HTP to serotonin. Elson Haas, M.D., author of "Staying Healthy with Nutrition," states that L-tryptophan is one of nine essential amino acids, meaning it cannot be manufactured in your body and must be acquired from your diet.

Serotonin Exerts Wide-Reaching Influence

Serotonin is intimately involved with the regulation of your moods, your sleep cycles and your responses to your environment. Abnormalities of serotonin production or function are believed to contribute to a variety of neurologic and psychiatric disorders, including depression. A 2010 review in "Dialogues in Clinical Neuroscience" reports that serotonin plays a regulatory role in nearly every region of your brain and practically every physiologic function in your body.

Serotonin is Compartmentalized

According to a 2010 study in "Endocrinology," serotonin that is produced outside of your brain cannot cross an anatomical boundary called the "blood-brain barrier." Thus, even if you could find dietary or supplemental sources of serotonin, they would not contribute significantly to serotonin levels in your brain. However, L-tryptophan and 5-HTP both readily cross the blood-brain barrier, so adding these precursors to your diet could theoretically increase serotonin levels in your central nervous system.

Considerations and Recommendations

There is no convincing evidence that taking extra L-tryptophan or 5-HTP can alleviate depression. In fact, according to a 2011 "Psychoneuroendocrinology" review, some studies suggest that genetic variations in the enzymes that synthesize serotonin in your brain could contribute to certain mood disorders, and these altered enzymes might not necessarily respond to increased levels of precursor molecules. Supplements containing L-tryptophan and 5-HTP in varying doses are commercially available. Some contain additional vitamin B6 to support the activity of converting enzymes. If you feel you need additional serotonin, speak with your physician to see if supplements are appropriate for you.