Nootropic profile
L-Tryptophan
L-Tryptophan is an essential amino acid and the precursor to serotonin and melatonin. It supports mood balance, promotes healthy sleep, and helps regulate appetite - serving as the upstream building block for the brain's key calming and sleep-regulating neurotransmitters.
Best for
Educational only: this is not medical advice. Always check with a qualified healthcare professional before starting any supplement.
What is L-Tryptophan?
L-Tryptophan is one of nine essential amino acids that the body cannot synthesise on its own, meaning it must be obtained from diet or supplementation.
What it does for you
Community and editorial ratings, out of 5:
How to take it
- Typical dose: 500–2,000 mg per day
- For sleep: 1,000–2,000 mg taken 30–45 minutes before bed, preferably on an empty stomach or with a small carbohydrate snack (to facilitate brain uptake)
- For mood: 500–1,000 mg, 2–3 times daily between meals
- Carbohydrate co-ingestion: Taking tryptophan with carbohydrates (but without competing amino acids from protein) improves its transport across the...
- With cofactors: Vitamin B6, iron, and magnesium are required for the conversion of tryptophan to serotonin - ensure adequate status of these nutrients
Watch out for
- Side effects: Generally well-tolerated. Possible drowsiness, nausea, or dizziness at higher doses. Heartburn or stomach discomfort in some individuals.
- Serotonin syndrome: Do NOT combine with SSRIs, SNRIs, MAOIs, or 5-HTP without medical supervision. The combination can lead to dangerous serotonin syndrome...
- Eosinophilia-Myalgia Syndrome (EMS): A 1989 outbreak was linked to a contaminated batch from a single manufacturer. Modern pharmaceutical-grade L-Tryptophan...
- Pregnancy: Consult a healthcare provider before use during pregnancy or breastfeeding.
- Liver/kidney disease: Use with caution in individuals with liver or kidney impairment, as tryptophan metabolism may be affected.
The science, if you're curious.
- L-Tryptophan is hydroxylated to 5-HTP, then decarboxylated to serotonin. Supplementation increases central serotonin availability, supporting mood...
- Serotonin produced from tryptophan is acetylated and methylated in the pineal gland to form melatonin, supporting circadian rhythm regulation and sleep onset.
- The majority (~95%) of tryptophan is metabolised through the kynurenine pathway, producing NAD+ (essential for cellular energy) and neuroactive metabolites...
- Tryptophan serves as a precursor to vitamin B3 (niacin/NAD+), supporting cellular energy metabolism throughout the brain.
Where to find it
- Turkey and poultry: Rich dietary sources (though the "turkey makes you sleepy" effect is largely a myth due to competing amino acids)
- Dairy products: Milk, cheese, and yoghurt contain significant tryptophan
- Eggs: Excellent source, particularly the egg white
- Nuts and seeds: Pumpkin seeds, sesame seeds, cashews, and almonds
- Supplements: Available as capsules, tablets, and powder in pharmaceutical-grade (USP/GMP) formulations
Frequently asked
L-Tryptophan is an essential amino acid and the precursor to serotonin and melatonin. It supports mood balance, promotes healthy sleep, and helps regulate appetite - serving as the upstream building block for the brain's key calming and sleep-regulating neurotransmitters.
The main benefits people report from L-Tryptophan are: Anxiety & Calm, Cognitive Enhancement, Focus, Mood, Sleep, Stress Relief.
Typical dose: 500–2,000 mg per dayFor sleep: 1,000–2,000 mg taken 30–45 minutes before bed, preferably on an empty stomach or with a small carbohydrate snack (to facilitate brain uptake)For mood: 500–1,000 mg, 2–3 times daily between mealsCarbohydrate co-ingestion: Taking tryptophan with carbohydrat...
Side effects: Generally well-tolerated. Possible drowsiness, nausea, or dizziness at higher doses. Heartburn or stomach discomfort in some individuals.Serotonin syndrome: Do NOT combine with SSRIs, SNRIs, MAOIs, or 5-HTP without medical supervision. The combination can lead to dangerous serotonin sy...
L-Tryptophan is hydroxylated to 5-HTP, then decarboxylated to serotonin. Supplementation increases central serotonin availability, supporting mood...Serotonin produced from tryptophan is acetylated and methylated in the pineal gland to form melatonin, supporting circadian rhythm regulation and sleep...
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