L-Tryptophan

Amino Acidoral · inferred

Essential large neutral amino acid used for protein synthesis and as the precursor of kynurenine-pathway metabolites, serotonin, and melatonin. Supplemental tryptophan raises plasma tryptophan, but brain entry depends on competition with other large neutral amino acids. Sleep and mood findings are heterogeneous and do not establish treatment of a disorder.

Projected serum levels — 1k mg, once daily

L-Tryptophan
L-Tryptophan modeled serum levels, 1k mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 125 250 375 500 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 1k mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 424 mg, trough ≈ 0.34 mg body load. Population-based estimate over 15 days for a 1k mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Amino Acid
Route modeled
Oral
Model confidence
inferred
Half-life
2 h
Common dose
1k mg
Suggested maximum
5k mg/day
Reference dose range
500–5k mg (single dose)
Suggested cadence
once daily

Research behind this entry

  1. Pharmacokinetics of tryptophan, renal handling of kynurenine and the effect of nicotinamide on its appearance in plasma and urine following L-tryptophan loading of healthy subjects Møller SE · European Journal of Clinical Pharmacology, 1981 DOI

    In six healthy participants given oral L-tryptophan 100 mg/kg, plasma tryptophan peaked at 1-2 hours, declined approximately linearly through hour 5, and then showed an exponential terminal phase through hour 8. This…

  2. The impact of tryptophan supplementation on sleep quality Sutanto CN, Loh WW, Kim JE · Nutrition Reviews, 2022 DOI

    Systematic review, meta-analysis, and meta-regression of 18 articles found a dose-related reduction in wake after sleep onset, with the clearer signal in studies using at least 1 g. The evidence did not show uniform…

  3. Supplementing healthy women with up to 5.0 g/d of L-tryptophan has no adverse effects Hiratsuka C et al. · The Journal of Nutrition, 2013 DOI

    In a randomized double-blind crossover study, 17 healthy young women received 0-5 g/day for 21 days per condition. General biomarkers, body weight, food intake, and mood-profile measures were not adversely changed,…

  4. Tryptophan supplementation and postoperative delirium--a randomized controlled trial. Robinson TN, Dunn CL, Adams JC, Hawkins CL, Tran ZV, Raeburn CD, Moss M · Journal of the American Geriatrics Society, 2014 DOI

    This citation reports a human clinical study involving L-Tryptophan. It does not by itself establish a qualified dose, safety profile, efficacy claim, or pharmacokinetic route for this record.

4 published studies referenced in the app, each with a plain-language summary.