The brain makes several chemicals that relay signals between different nerve cells. One of these chemicals is serotonin, which is derived from an amino acid called tryptophan. Serotonin affects your mood, appetite, sleep and digestion. Low serotonin levels may contribute to depression, obsessive-compulsive disorder, anxiety and poor anger management. While brain serotonin levels can be altered by prescription medications, there are several ways you may be able to increase the serotonin in your brain without drugs. These include exercise, exposure to sunlight and eating certain foods.

Getting Physical

Exercise is one way to increase your body's production of serotonin. Not only does exercise increase the amount of serotonin released into your brain, but it also increases the amount of tryptophan in your brain, the amino acid that is the precursor of serotonin. As more tryptophan becomes available to your brain, more serotonin will be produced. Exercise also increases the release of other chemicals in your brain such as dopamine, which further contributes to improving your mood.

Bright Lights

Your outlook is generally more positive on a bright, sunny day than on a rainy, overcast day. One explanation may be that exposure to bright light increases serotonin in your brain. In fact, bright light, whether natural or artificial, is an effective treatment for individuals with seasonal affective disorder, a type of depression that occurs during the winter months as the days become shorter and exposure to sunlight decreases. In healthy individuals, sunlight has positive effects on brain serotonin levels and mood.

High-Tryptophan Foods

While you would expect that eating foods containing high levels of serotonin would increase the level of serotonin in your brain, serotonin is unable to travel from the bloodstream into the brain. Tryptophan can get into the brain, however. Thus, eating foods high in tryptophan -- such as meats, bananas, nuts, seeds, tofu, eggs, dark chocolate and lentils -- indirectly increases the amount of serotonin in the brain. A high-carbohydrate diet may improve the transportation of tryptophan into the brain, although this effect may be only short-lived.

Massage Therapy

Massage therapy may be another way to increase your serotonin levels. According to an article published in the October 2005 issue of the “International Journal of Neuroscience,” regular massages in women with prenatal depression improved their mood and increased the amount of serotonin and dopamine found in their urine. While the actual levels of these substances in the brain were not measured, these results suggest that they were increased. Regular massage therapy can also reduce the levels of cortisol -- a stress hormone.

Natural Supplements

Several natural remedies may increase serotonin levels and improve mood. These include St. John's wort, which is derived from a natural herb, and L-tryptophan. Both are available without a prescription. Prior to taking these supplements, however, talk to your doctor, especially if you're taking any other supplements or medications. St. John’s wort, in particular, may cause problems when used with several medications, including contraceptives, anticoagulants and heart medications. Furthermore, excessive intake of any supplement that increases serotonin levels may result in serotonin syndrome, which is a condition characterized by such symptoms as confusion, diarrhea, agitation and hallucinations.