Citable fact
«Tryptophan» — evidence level C. Dosage: Dietary doses of 0.5–2 g to affect sleep and mood; sports studies used 1.2–3 g before exercise. Single doses above 5 g are not recommended. Source: PMID 3246461, permanent link to the source in the list below.
How it works
Tryptophan is an essential amino acid and a precursor of serotonin and melatonin. When taken without other large neutral amino acids, it crosses the blood-brain barrier more easily and increases serotonin synthesis in the brain. Serotonin is involved in the regulation of sleep, mood and the perception of fatigue. Theoretically, a rise in serotonin during prolonged exercise is linked to central fatigue — that is, the effect may be rather unfavorable for endurance.
Dosage and intake
Dietary doses of 0.5–2 g to affect sleep and mood; sports studies used 1.2–3 g before exercise. Single doses above 5 g are not recommended
For sleep — 30–60 minutes before going to bed, separately from protein food. Intake before training is not recommended
Forms
Free L-tryptophan, powder or capsules. Tryptophan is present in proteins but competes with other amino acids for transport
What is confirmed
- May slightly shorten the time to fall asleep and improve subjective sleep quality
- Serves as a precursor of serotonin and melatonin
- Part of the normal diet as a component of complete protein
Adverse effects and limitations
- Does not improve physical performance and is not an ergogenic aid
- Sports data come from a few old small studies and have not been reproduced
- Drowsiness, dizziness and nausea are possible; before exercise — reduced concentration
- Serotonin syndrome when combined with serotonergic drugs
Interactions
- With antidepressants (SSRIs, MAOIs, triptans) — risk of serotonin syndrome
- With sedatives and hypnotics — increased drowsiness
- With other sources of tryptophan and 5-hydroxytryptophan — additive effect
Who must not use it
- Under 18 years: There are no data on supplement use by children and adolescents; not recommended
- Pregnancy and lactation: Intake at doses above dietary levels during pregnancy and lactation has not been studied
- Antidepressant and other serotonergic drug use — contraindicated without a doctor
- Liver failure — impaired tryptophan metabolism
- Excessive daytime sleepiness, driving — a limitation
Sources
See also
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