Good health depends on a complex interplay between chemicals that is precise and sometimes very subtle. Your body makes neurotransmitters using ingredients it manufactures or takes from your diet. Dietary supplements may promote or upset this complex process. For example, melatonin and 5-HTP, or 5-hydroxytryptophan, work differently, but are linked closely together through a common chemical production process. Taking these two substances together may produce unintended consequences. Always consult your physician before you combine any dietary supplements to treat a medical condition.
Melatonin is a naturally occurring substance that helps regulate your body's sleep-wake cycle. Most melatonin is produced and released by the pineal gland, located in the brain. Melatonin synthesis begins with the amino acid L-tryptophan. First, L-tryptophan is converted into 5-HTP. Next, 5-HTP is converted to serotonin, which is then metabolized further to create melatonin. Melatonin does not function like the neurotransmitter serotonin; instead, it triggers the sleep cycle by interacting with its own receptors in the brain.
Your body does not use the amino acid 5-HTP directly. Its benefits come instead from the substances your body produces with it. Serotonin is a neurotransmitter essential for gastrointestinal, nervous system, cardiovascular, skeletal and psychological health. 5-HTP supplements are sometimes used as sleep aids, but it is serotonin that has the antidepressant, mood elevating and anti-anxiety effects that make sleep possible. Very little 5-HTP comes from the foods you eat. Instead, your body produces 5-HTP from the tryptophan found in protein-rich foods like eggs, meat, fish and dairy products.
Melatonin Drug Interactions
The National Institutes of Health website MedlinePlus lists many possible melatonin drug interactions. Melatonin may cause health problems when taken with birth control pills, caffeine, fluvoxamine, anti-diabetes drugs, immuno-suppressants, anticoagulant or anti-platelet drugs, nifedipine, verapamil or flumazenil. In addition, melatonin's sedative effects will compound those of other medicines or supplements which cause drowsiness such as valerian, catnip, hops, kava, over-the-counter sleep aids, sedating antihistamines and prescription drugs with nervous system-depressing effects.
Melatonin and 5-HTP
There are no direct harmful interactions between melatonin and 5-HTP. The safety of combining the two depends upon the interaction of melatonin with serotonin. While serotonin is needed for melatonin production, supplemental 5-HTP does not directly increase melatonin levels. The conversion of serotonin to melatonin can be reversed. Increased serotonin from supplemental 5-HTP and melatonin may lead to serotonin syndrome, a potentially life threating condition caused by high serotonin levels. Symptoms of serotonin syndrome include agitation, diarrhea, fast heart beat, hallucinations, loss of coordination and changes in blood pressure.
- Systematic Reviews in Pharmacy: Melatonin, Receptors, Mechanism, and Uses
- MedlinePlus: Melatonin
- Natural Medicine Journal: An Evidence-Based Systematic Review of Melatonin Interactions by The Natural Standard Research Collaboration
- MedlinePlus: Serotonin Syndrome
- University of Maryland Medical Center: Melatonin
- University of Maryland Medical Center: Possible Interactions with: 5-Hydroxytryptophan (5-HTP)
- Utox Update: Serotonin Syndrome
- Imperial College London: Chemical Synthesis of Melatonin
- Pharmacorama Drug Knowledge: Serotonin - Metabolism