L-Tryptophan

Essential aromatic amino acid crucial for serotonin synthesis, sleep regulation, and mood support

Scientific nameL-Tryptophan FormulaC11H12N2O2 Molecular weight204.23 g/mol CAS73-22-3

80 absorption score

6 safety / 10

30 USD per month

5 documented interactions

Check it against something

Evidence level A

L-Tryptophan with:

82 out of 100

Works better together Compatible. Timing differs, so follow each supplement's own window.

Check it against your whole stack →

What it does

mechanism and evidence for each claim

Improved sleep quality and duration

Supports natural sleep patterns and restful sleep

Converted to serotonin and then melatonin for sleep regulation Evidence A-grade 1-4 weeks

Enhanced mood and emotional well-being

Supports positive mood and emotional balance

Precursor to serotonin neurotransmitter for mood regulation Evidence B-grade 2-6 weeks

Reduced anxiety and stress

Promotes relaxation and stress reduction

Serotonin production supports calm and relaxed state Evidence B-grade 1-4 weeks

Appetite regulation support

Helps regulate appetite and food cravings

Serotonin influences satiety and appetite control Evidence B-grade 2-6 weeks

Pain management support

May help with pain perception and tolerance

Serotonin pathways involved in pain modulation Evidence C-grade 2-8 weeks

Others take these for the same thing

Same goal, different mechanism — check any of them against this one

Melatonin Sleep support & circadian rhythm 0.5-3mg A 50% Ashwagandha Stress management & energy 300-600mg A 75% Magnesium Glycinate Superior absorption sleep & muscle support 200-600 mg A 90% Vitamin B12 (Cyanocobalamin) Energy & nerve support 250-1000 mcg A 70% Fish Oil (EPA/DHA) Heart & brain health 1-2g EPA/DHA A 85% L-Theanine Calm focus & stress relief 100-400mg B 90%

Every pair we checked

12 combinations scored by the engine

L-Tryptophan + Caffeine No documented interaction either way No known interaction 70

L-Tryptophan + Creatine Monohydrate No documented interaction either way No known interaction 70

L-Tryptophan + Calcium Carbonate No documented interaction either way No known interaction 70

L-Tryptophan + Whey Protein No documented interaction either way No known interaction 70

L-Tryptophan + Lactase No documented interaction either way No known interaction 70

L-Tryptophan + Bovine Collagen No documented interaction either way No known interaction 70

L-Tryptophan + DHA No documented interaction either way No known interaction 70

L-Tryptophan + Turmeric No documented interaction either way No known interaction 70

L-Tryptophan + Fish Oil (EPA/DHA) No documented interaction either way No known interaction 70

L-Tryptophan + Marine Collagen No documented interaction either way No known interaction 70

L-Tryptophan + Magnesium Oxide Enhances relaxation and sleep quality Works better together 78

L-Tryptophan + Vitamin D3 Required for serotonin synthesis from tryptophan Works better together 82

Dosage

Bedtime empty stomach

Daily500-2000mg

Sleep support500-2000mg at bedtime

Mood enhancement500-1500mg daily

Anxiety reduction500-1000mg daily

Upper limit6g daily (divided doses)

Before you take it

VeganYes

When to expect it

First Effects30 minutes to 2 hours for sleep benefits

Peak Benefits2-6 weeks for sustained mood and sleep improvements

Deficiency DevelopmentWeeks to months with inadequate protein intake

Toxicity OnsetRare, mainly drug interaction concerns

How to measure it

$100-200

MarkerPlasma tryptophan, serotonin, or kynurenine pathway metabolites

OptimalTryptophan: 40-80 μmol/L

Deficient below<30 μmol/L

FrequencyOnly if monitoring mood disorders or sleep issues

What people actually reported to the FDA

CAERS, 16 reports naming it as the suspect

Most reported effects

Muscle spasms 5

Fatigue 4

Myalgia 3

Pain 3

Asthenia 2

Named as the suspect 16 reports of 19 that mention it at all

Serious outcome 71% hospitalisation, emergency room or worse

Other Serious or Important Medical Event7

Disability5

Hospitalization3

Reports are voluntary and unverified — they record what someone experienced while taking something, not what the compound caused. Counts skew towards products people take a lot of, and a serious outcome is more likely to be reported than a mild one, so these are not rates. How we filter them →

What actually reaches you

The label counts the carrier, your body does not

Absorption Very high 80 of 100 · best absorbed form of this compound

Delivered daily 1000 mg

Cost per 100 mg delivered $0.10 comparative — uses the absorption score, not a measured percentage

Works better with

3 documented

Vitamin B6

Required for serotonin synthesis from tryptophan

Cofactor for aromatic amino acid decarboxylase · level A

Magnesium

Enhances relaxation and sleep quality

Complementary effects on nervous system relaxation · level B

Carbohydrates

Improve tryptophan brain uptake

Insulin release reduces competing amino acids · level A

What not to take with L-Tryptophan

2 documented

Other Large Amino Acids

Compete with tryptophan for brain uptake

Shared large amino acid transporter · major significance

Protein Meals

Protein reduces tryptophan brain uptake

Competition with other amino acids · major significance

Medication interactions

Discuss these with a pharmacist before combining

ssri-antidepressants Major

Risk of serotonin syndrome

What to do: Avoid combination or use under medical supervision

mao-inhibitors Major

Severe risk of serotonin syndrome

What to do: Contraindicated

sedatives-sleep-aids Moderate

Additive sedative effects

What to do: Reduce doses, monitor for excessive sedation

Available forms

bioavailability compared

L-Tryptophan (Free Form) 80

L-Tryptophan (Free Form): Natural sleep support, Mood enhancement, Well-researched, Effective for insomnia

Food sources

before you supplement

Turkey and poultry 0.2-0.3g per 100g · 70

Fish and seafood 0.2-0.3g per 100g · 70

Dairy products 0.1-0.2g per 100g · 65

Nuts and seeds 0.1-0.2g per 100g · 60

Too little

deficiency signs

Insomnia and poor sleep quality
Depression and mood disorders
Anxiety and irritability
Increased appetite and cravings
Poor stress tolerance
Pellagra symptoms (niacin deficiency)
Impaired immune function

Too much

toxicity signs

Rare with pure L-tryptophan:
Serotonin syndrome (with drugs)
Excessive drowsiness
Nausea and digestive upset
Generally good safety profile

Who benefits most

sleep-disorders-insomnia

Supports natural sleep regulation and quality

500-2000mg 30-60 minutes before bed

mood-support-depression

Supports serotonin production for mood enhancement

500-1500mg daily (away from protein)

anxiety-stress-management

Promotes relaxation and stress reduction

500-1500mg daily

appetite-weight-control

Helps regulate appetite and reduce cravings

500-1000mg before meals

chronic-pain-management

May help with pain perception through serotonin pathways

500-1500mg daily

Where to buy it

compare forms first

Look for L-Tryptophan at 500-2000mg per serving. The form that matters here is L-Tryptophan (Free Form).

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What else affects it

Beyond other supplements

Carbohydrates

Improve tryptophan brain uptake

Insulin release reduces competing amino acids

Protein meals

Protein reduces tryptophan brain uptake

Competition with other amino acids

How it works

Converted to 5-HTP and then serotonin neurotransmitter
Serotonin converted to melatonin for sleep regulation
Influences mood through serotonin pathways in brain
Affects appetite and satiety through serotonin signaling
Involved in pain modulation through serotonin receptors
Can be converted to niacin (vitamin B3) when needed

Key findings

what the evidence supports

Effective for improving sleep quality and reducing sleep latency
Essential precursor to serotonin neurotransmitter
May support mood enhancement and depression treatment
Requires careful timing and drug interaction monitoring

Sources: NIH Examine.com · data reviewed 2026-08-02

Compiled by Denis, who maintains this database and holds no medical qualification — every figure here is sourced or derived, never asserted. How we calculate it →

Common questions

What are the benefits of L-Tryptophan?

Documented effects: Improved sleep quality and duration; Enhanced mood and emotional well-being; Reduced anxiety and stress; Appetite regulation support. Supports natural sleep patterns and restful sleep

How much L-Tryptophan should you take per day?

The common daily range is 500-2000mg. By goal — sleep support: 500-2000mg at bedtime; mood enhancement: 500-1500mg daily; anxiety reduction: 500-1000mg daily; upper limit: 6g daily (divided doses).

When is the best time to take L-Tryptophan?

Bedtime empty stomach. First effects are typically reported within 30 minutes to 2 hours for sleep benefits.

What are the side effects of L-Tryptophan?

At excessive doses: Rare with pure L-tryptophan:, Serotonin syndrome (with drugs), Excessive drowsiness, Nausea and digestive upset, Generally good safety profile. Safety rating at normal doses is 6 out of 10.

What should you not take with L-Tryptophan?

Separate it from Other Large Amino Acids, Protein Meals by two to four hours. Compete with tryptophan for brain uptake

Does L-Tryptophan interact with medications?

Documented interactions with ssri-antidepressants, mao-inhibitors, sedatives-sleep-aids. Discuss these with a pharmacist before combining.

How do you know if you need L-Tryptophan?

The marker is Plasma tryptophan, serotonin, or kynurenine pathway metabolites, optimal range Tryptophan: 40-80 μmol/L. Common deficiency signs: Insomnia and poor sleep quality, Depression and mood disorders, Anxiety and irritability, Increased appetite and cravings.

Taken for

52 Brain & Focus

Caffeine · DHA · Fish Oil (EPA/DHA)

28 Sleep & Stress

Melatonin · Magnesium Glycinate · Ashwagandha