Products
In many countries, tryptophan is commercially available as a dietary supplement, for example, in the form of capsules.
Structure and properties
L-tryptophan (C11H12N2O2, Mr = 204.2 g/mol) is an essential aromatic amino acid derived from indole. It exists as a white, crystalline or amorphous powder that is sparingly soluble in water.
Effects
Tryptophan (ATC N06AX02) has sleep-promoting and serotonergic properties and may affect mood. It is a precursor of the neurotransmitters serotonin and melatonin, among others. Tryptophan crosses the blood–brain barrier and is metabolized via 5-hydroxytryptophan to serotonin.
Indications
Tryptophan is approved in Germany for the treatment of sleep disorders. In addition, other uses exist, such as depression and other psychiatric disorders.
Dosage
According to the professional information. Adults take 1000 mg to 2000 mg half an hour before bedtime. For dietary supplements, the recommended dose may be lower.
Contraindications
- Hypersensitivity
- Severe hepatic insufficiency (severe liver dysfunction).
- Hepatic encephalopathy
- Severe renal disease, renal insufficiency.
- Small bowel carcinoid with cardiac damage (Hedinger syndrome).
- Concurrent treatment with MAO inhibitors, SSRIs, or amphetamines.
- Children and adolescents (insufficient data)
For complete precautions, see the drug label.
Interactions
Drug-drug interactions have been described with antiepileptic drugs, antihypertensives, levodopa, opioids, dextromethorphan, and psychotropic drugs such as SSRIs, SSNRIs, MAO inhibitors, benzodiazepines, lithium, tricyclic antidepressants, and phenothiazines. Concurrent use of other serotonergic drugs may result in serotonin syndrome.
Adverse effects
Possible adverse effects include dizziness, headache, sensitivity to light, dullness, lingering fatigue, and low blood pressure.