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Amino acids and derivatives

L-Tryptophan

Also known as tryptophan, L-Tryptophane, Tryptophane

CAS 73-22-3Formula C11H12N2O2Molar mass 204.23 g/molEC 200-795-6
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L-Tryptophan chemical structure, C11H12N2O2, CAS 73-22-3
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Leaflets or plates from dilute alcohol
Melting point
282 °C
Solubility
Solubility in water: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L a…
HS code
293399
Category
Amino acids and derivatives
Illustrative photo, closed white HDPE bottles and amber jars on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is L-Tryptophan?

Plain description, key identifiers and synonyms

L-tryptophan is the L-enantiomer of tryptophan. It has a role as a micronutrient, an antidepressant, a nutraceutical, a mouse metabolite, a Saccharomyces cerevisiae metabolite, a plant metabolite, an Escherichia coli metabolite and a human metabolite. It is a L-alpha-amino acid, a tryptophan, an erythrose 4-phosphate/phosphoenolpyruvate family amino acid and a proteinogenic amino acid. It is a conjugate base of a L-tryptophanium. It is a conjugate acid of a L-tryptophanate. It is an enantiomer of a D-tryptophan. It is a tautomer of a L-tryptophan zwitterion.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
(2S)-2-amino-3-(1H-indol-3-yl)propanoic acid
CAS number
73-22-3 CAS number cross-checkedOther or deprecated CAS: 202406-50-6, 54-12-6, 80206-30-0
EC number
200-795-6
Molecular formula
C11H12N2O2
UNII
8DUH1N11BX
MDL number
MFCD00064340
InChIKey
QIVBCDIJIAJPQS-VIFPVBQESA-N
InChI
InChI=1S/C11H12N2O2/c12-9(11(14)15)5-7-6-13-10-4-2-1-3-8(7)10/h1-4,6,9,13H,5,12H2,(H,14,15)/t9-/m0/s1
Canonical SMILES
NC(Cc1c[nH]c2ccccc12)C(=O)O
Isomeric SMILES
C1=CC=C2C(=C1)C(=CN2)C[C@@H](C(=O)O)N

Synonyms

  • tryptophan
  • L-Tryptophane
  • Tryptophane
  • (S)-Tryptophan
  • trofan
  • tryptacin
  • (2S)-2-amino-3-(1H-indol-3-yl)propanoic acid
  • Ardeytropin
  • Pacitron
  • Indole-3-alanine
  • L-Tryptofan
  • L-Trp
  • L-(-)-Tryptophan
  • L-beta-3-Indolylalanine
  • 3-Indol-3-ylalanine
  • triptofano
  • (-)-Tryptophan
  • 1-beta-3-Indolylalanine
  • Tryptophan, L-
  • 1H-Indole-3-alanine
  • Tryptophanum
  • 1beta-3-Indolylalanine
  • 2-Amino-3-indolylpropanoic acid
  • (l)-Tryptophan
  • (S)-alpha-Amino-1H-indole-3-propanoic acid
Show all 38 synonyms
  • alpha'-Amino-3-indolepropionic acid
  • L-alpha-Aminoindole-3-propionic acid
  • (S)-alpha-Aminoindole-3-propionic acid
  • L-alpha-amino-3-indolepropionic acid
  • EH 121
  • Alanine, 3-indol-3-yl-
  • Trytophan-
  • L-Alanine, 3-(1H-indol-3-yl)-
  • 1H-Indole-3-alanine, (S)-
  • Indole-3-propionic acid, alpha-amino-
  • Propionic acid, 2-amino-3-indol-3-yl-
  • (S)-alpha-amino-beta-(3-indolyl)-propionic acid
  • 1H-Indole-3-propanoic acid, alpha-amino-, (S)-

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Leaflets or plates from dilute alcoholexp.
Odour
Odorlessexp.
Taste
FLAT TASTEexp.
Melting point
282 °Cexp.
Solubility
Solubility in water: 0.23 g/L at 0 °C, 11.4 g/L at 25 °C, 17.1 g/L at 50 °C, 27.95 g/L at 75 °C, 49.9 g/L at 100 °Cexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
204.23 g/molcalc.
Exact mass
204.0899 Dacalc.
LogP (octanol/water)
1.12calc.
Topological polar surface area
79.11 Ųcalc.
Hydrogen bond donors
3calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
3calc.
Heavy atoms
15calc.
Rings
2calc.
Aromatic rings
2calc.
Fraction sp3 carbons
0.18calc.
Formal charge
0calc.
Stereocentres
1calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, c1ccc2[nH]ccc2c1

c1ccc2[nH]ccc2c1

2 rings, 9 atoms, the Indole ring system.

25,097 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS classification
Hazard pictograms

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

L-Tryptophan suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 256 suppliers
30 of 30 offers

Suppliers marked Unclaimed profile have not claimed their profile yet. They are not verified by CompoundList, their offers are price on request and details may have changed, so please confirm them with the supplier. Company representatives can claim a profile with a business email on the company's own website domain. Our team verifies each claim and sends the result by email.

Where suppliers are based

256 suppliers in 37 countries

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L-Tryptophan price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Nutrition and research, medicine, dietary supplement, cereal enrichment (Tryptophan).

Probe for studying protein structure and dynamics.

Nutritional supplement (amino acid) in drugs and foods.

Biological activities: Analgesic, Antidementia, Antidepressant, Antidyskinetic, Antihypertensive, Antiinsomniac, Antimanic, Antimenopausal, Antimigraine, Antioxidant, Antiparkinsonian, Antiphenylketonuric, Antiprostaglandin, Antipsychotic, Antirheumatic, Antiscolioticn,, Carcinogenic, Essential, Hypnotic, Hypoglycemic, Hypotensive, Insulinase-Inhibitor, Insulinotonic, Monoamine-Precursor, Prolactinogenic, Sedative, Serotoninergic, Tumor-Promoter (Tryptophan).

Use classes: Cosmetics.

Pharmacological actions

  • Antidepressive Agents, Second-Generation

Roles

  • Escherichia coli metabolite
  • Saccharomyces cerevisiae metabolite
  • animal metabolite
  • antidepressant
  • bacterial metabolite
  • central nervous system drug
  • eukaryotic metabolite
  • food component
  • fungal metabolite
  • human metabolite
  • mammalian metabolite
  • metabolite
  • micronutrient
  • mouse metabolite
  • nutraceutical
  • nutrient
  • pharmaceutical
  • physiological role
  • plant metabolite
  • prokaryotic metabolite
  • psychotropic drug

Functional uses

  • Flavouring and nutrient

Pharmacology

Tryptophan is the least plentiful of all 22 amino acids and an essential amino acid in humans (provided by food), Tryptophan is found in most proteins and a precursor of serotonin. Tryptophan is converted to 5-hydroxy-tryptophan (5-HTP), converted in turn to serotonin, a neurotransmitter essential in regulating appetite, sleep, mood, and pain. Tryptophan is a natural sedative and present in dairy products, meats, brown rice, fish, and soybeans. (NCI04)

How it is made

Fermentation of natural or biologically available substances with Corynebacterium glutamicum, enzymatically from indole, pyruvic acid, and ammonia using microbial tryptophanase

Synthesis starting with beta-indolylaldehyde and hippuric acid, ... from hydantoin, alternate route starting with 3-indoleacetonitrile.

Regulatory status

Inventories, regulations and trade controls that list this substance

Health and food

  • Active ingredient in FDA approved drug labels

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code L-Tryptophan is traded under.

HS 2933.99Indicative HS code

Heterocyclic compounds with nitrogen hetero-atom(s) only, other

World exports in 2024
$12.1B
−31.0% vs 2023, imports $28.8B
2019 to 2024
Top exporters
  1. China30.5%
  2. India * partner reported16.3%
  3. Ireland9.0%
Top importers
  1. Slovenia31.7%
  2. Italy24.2%
  3. United States5.0%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for L-Tryptophan is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about L-Tryptophan, based on the data on this page

What is L-Tryptophan?

L-tryptophan is the L-enantiomer of tryptophan. It has a role as a micronutrient, an antidepressant, a nutraceutical, a mouse metabolite, a Saccharomyces cerevisiae metabolite, a plant metabolite, an Escherichia coli metabolite and a human metabolite.

What is the CAS number of L-Tryptophan?

The CAS registry number of L-Tryptophan is 73-22-3. Other or deprecated CAS numbers: 202406-50-6, 54-12-6, 80206-30-0.

What is the molecular formula and weight of L-Tryptophan?

The molecular formula of L-Tryptophan is C11H12N2O2 and its molar mass is 204.23 g/mol.

What is L-Tryptophan used for?

Nutrition and research, medicine, dietary supplement, cereal enrichment (Tryptophan). Probe for studying protein structure and dynamics. Nutritional supplement (amino acid) in drugs and foods.

Is L-Tryptophan hazardous?

No GHS hazard classification for L-Tryptophan is recorded on CompoundList yet. That does not prove it is safe. Always read the supplier safety data sheet.

What is the HS code of L-Tryptophan?

L-Tryptophan is usually classified under HS code 293399 (Heterocyclic compounds with nitrogen hetero-atom(s) only, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy L-Tryptophan?

CompoundList lists 256 suppliers of L-Tryptophan in China, United States, India, Germany and 33 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy L-Tryptophan in India?

20 suppliers in India list L-Tryptophan on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of L-Tryptophan?

Suppliers quote L-Tryptophan on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle L-Tryptophan

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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