Your serotonin brain cells produce serotonin when an amino acid called 5-Hydroxy-Tryptophan (5-htp) enters the cell and comes into contact with an enzyme called decarboxylese. The 5-htp enters the cell directly through the cell's membrane. It does not have to go through the reuptake transporters, the way previously-released serotonin must. Once in the axon, decarboxylase turns the 5-htp into serotonin, where it enters the vesicles (the vesicles are not shown in this diagram). In other words, after the serotonin is made inside the cell, it moves to the terminal where it is stored in the vesicles ready to be released into the synapse when the time comes.

There's usually plenty of decarboxylase in your cells, but the amount of 5-htp you have can vary depending on your diet. 5-htp is synthesized in your body from another amino acid called tryptophan, which is contained in many foods. A diet high in tryptophan-containing proteins can increase the amount of 5-htp in your brain, and thus help your brain build serotonin more quickly.

Normally it takes a long time for your brain to build serotonin. Why? One reason is that tryptophan must go through a number of metabolic changes before it is turned into 5-htp. Another reason is simply that your brain was not made to make serotonin very quickly. Normally, it doesn't need to, because serotonin is not usually released in very large quantities. As a comparison, dopamine is released in larger quantities under normal circumstances, and your brain is thus built to replenish dopamine much more quickly. Researchers say that the dopamine system is "robust" in this sense, while the serotonin system is "delicate."

Some ecstasy users take 5-htp supplements to restore their depleted serotonin levels more quickly. For information on using 5-htp in this way, see our page on general health and safety.)