A precursor is a substance that serves as a building block for other chemicals in the body. Through a complex chemical transformation requiring several different steps, our bodies use precursors to produce neurotransmitters (chemical messengers), which allow neurons (nerve cells) to communicate with each other.
5-hydorxytryptophan (5-HTP) is a compound made from the amino acid (protein) tryptophan, and is primarily found in the brain. 5-HTP is one of the basic building blocks or precursors for serotonin, a neurotransmitter thought to be responsible for mood regulation. Individuals who experience anxiety (and depression) have reduced levels of serotonin in their brains.
Antidepressant medications such as the selective serotonin reuptake inhibitors (SSRI) and monoamine oxidase inhibitors (MAOI) are commonly used to treat anxiety. These medications work by increasing the total amount of serotonin in the brain or by allowing the serotonin that is already there to work longer before being broken down. Serotonin itself can be manufactured, but when taken as a supplement, it cannot reach the brain (it does not have the ability to cross from general blood circulation into brain circulation, because of a selective membrane that only allows certain chemicals to cross). 5-HTP came into use in an effort to find a natural way to increase brain serotonin levels. Multiple research studies have confirmed this effect and demonstrated 5-HTP's ability to increase serotonin levels when taken as a supplement. Interestingly, while research supporting the use of 5-HTP for depression is strong, the research supporting its use in anxiety is less convincing.
Safety and Dosing
A typical dose of 5-HTP is between 100-300 mg a day. 5-HTP must not be combined with any other antidepressant medication because of the risk of a rare condition called serotonin syndrome (or serotonin toxicity) that produces mental confusion, agitation, headache, shivering, sweating, hypertension, tachycardia (fast heart rate), and other symptoms.
Side Effects of 5-HTP
- Mild stomach upset
- Tachycardia (fast heart rate)
There is a small risk of developing liver toxicity when using 5-HTP. L-tryptophan, a closely related chemical, was pulled from shelves in 1989 when it was associated with liver failure in a few people. While it appears that 5-HTP does not have this problem, it is best to check with your health practitioner before starting any new medication, especially if your medical history includes previous or current liver problems.