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  • industrial
  • pharma

Methionine

CAS 63-68-3 · 60/100 · High conf.

Also registered as 33 other CAS numbers

3654-96-4 · 58576-49-1 · 7005-18-7 · 24425-78-3 · 1437749-32-0 · 1437749-60-4 · 1437749-65-9 · 1437749-75-1 · 1437749-80-8 · 1437769-00-0 · 1437870-94-4 · 1437870-95-5 · 1437870-97-7 · 1437870-98-8 · 1437871-20-9 · 1463481-01-7 · 1463481-06-2 · 1463481-15-3 · 1463481-19-7 · 1463481-23-3 · 1463481-27-7 · 1463481-31-3 · 1463481-37-9 · 1463481-41-5 · 1463481-46-0 · 1463481-51-7 · 1463481-58-4 · 1463481-73-3 · 1463481-80-2 · 1463481-89-1 · 1463610-75-4 · 1463610-76-5 · 1466415-57-5

Methionine chemical structure

Concern score

60/100High concern based on regulatory listings.
High confidence

Methionine in plain language

What it is

Also known as L-methionine · (2S)-2-amino-4-methylsulfanylbutanoic acid · (2S)-2-AMINO-4-(METHYLSULFANYL)BUTANOIC acid · (S)-2-Amino-4-(methylthio)butanoic acid · 2-Amino-4-(methylthio)butyric acid · 2-Amino-4-methylthiobutanoic acid

Show all 25 names

Acimethin · Butanoic acid, 2-amino-4-(methylthio)-, (S)- · Cymethion · L(-)-Amino-gamma-methylthiobutyric acid · L- Methionine · L-Homocysteine, S-methyl- · L-Met · L-Methionin · L-Methioninum · L-alpha-Amino-gamma-methylmercaptobutyric acid · L-alpha-Amino-gamma-methylthiobutyric acid · L-gamma-Methylthio-alpha-aminobutyric acid · Methionine, l- · Methilanin · Methioninum · Neo-methidin · S-Methionine · h-Met-oh · metionina

What it does

Used in consumer products as a flavouring and a conditioner.

  • Flavouring
  • Conditioner
Is it a concern?
High concern: no hazard classifications on record.

Why it's flagged

EPA CPDat observed this chemical in 3 composition records across product categories including Raw materials, Laboratory supplies, Food and drug.

The score describes this ingredient's chemical identity — its hazard profile from published classifications and regulatory status — not the safety of any product it appears in.

Regulation

No restrictions found. Methionine appears in these published regulatory listings.

  • In marketed US drugs
  • Inactive ingredient in US drugs

Recorded in these product areas

  • Found in consumer products
  • Pharma
  • Food
  • Industrial
  • USFDAinactive ingredient database7 entries — 4 administration routes
    • Route: ORAL; Dosage form: TABLET; Potency: NASource →
    • Route: SUBCUTANEOUS; Dosage form: INJECTION; Potency: 0.15 %w/vSource →
    • Route: SUBCUTANEOUS; Dosage form: INJECTION, SUSPENSION; Potency: 0.15 %w/vSource →
    • Route: SUBCUTANEOUS; Dosage form: SUSPENSION; Potency: 0.15 %w/vSource →
    • Route: INTRAVENOUS; Dosage form: INJECTION, SOLUTION; Potency: 0.16 %w/vSource →
    • Route: INTRAVENOUS; Dosage form: INJECTION; Maximum daily exposure: 16 mgSource →
    • Route: INTRATHECAL; Dosage form: INJECTION; Potency: 0.01 %w/vSource →
  • EUEFSAEFSA opinion3 entries
    • Scientific Opinion on the safety and efficacy of the use of amino acids (chemical group 34) when used as flavourings for all animal species (EFSA FEEDAP)Source →
    • Amino acids from chemical group 34. Flavouring Group Evaluation 26, Revision 1. Scientific opinion of the Panel on Food Additives, Flavourings, Processing Aids and Materials in contact with Food (AFC) (EFSA AFC)Source →
    • Scientific Opinion on the safety and efficacy of L-methionine produced by Escherichia coli (KCCM 11252P) and Escherichia coli (KCCM 11340P) for all animal species (EFSA FEEDAP)Source →
  • USEPAcommercial use observedEPA CPDat observed this chemical in 3 composition records across product categories including Raw materials, Laboratory supplies, Food and drug. EPA CPDat classifies this chemical for functional uses including Active ingredient, Flavouring and nutrient, Softener and conditioner.
    • EPA CPDat observed this chemical in 3 composition records across product categories including Raw materials, Laboratory supplies, Food and drug. EPA CPDat classifies this chemical for functional uses including Active ingredient, Flavouring and nutrient, Softener and conditioner.Source →
  • USFDAmarketed drug occurrenceFDA NDC lists this ingredient in 65 active drug products and 69 total products.
    • FDA NDC lists this ingredient in 65 active drug products and 69 total products.Source →
  • USFDAlisted in openFDA substanceopenFDA substance registry classifies this ingredient as chemical.
    • openFDA substance registry classifies this ingredient as chemical.Source →

Expert safety opinions

Independent scientific assessments cited by the records we hold, with the year and link where the record gives one.

  • JECFA

    Joint FAO/WHO Expert Committee on Food Additives

    No JECFA evaluation on file.

  • EFSA

    European Food Safety Authority

    • Scientific Opinion on the safety and efficacy of the use of amino acids (chemical group 34) when used as flavourings for all animal species (EFSA FEEDAP)

      2014 · EU EFSA listing · Read the source →

    • Amino acids from chemical group 34. Flavouring Group Evaluation 26, Revision 1. Scientific opinion of the Panel on Food Additives, Flavourings, Processing Aids and Materials in contact with Food (AFC) (EFSA AFC)

      2008 · EU EFSA listing · Read the source →

    • Scientific Opinion on the safety and efficacy of L-methionine produced by Escherichia coli (KCCM 11252P) and Escherichia coli (KCCM 11340P) for all animal species (EFSA FEEDAP)

      2013 · EU EFSA listing · Read the source →

Evidence & sources

No graded research studies for Methionine yet. This record is compiled from the published data sources below — registries and regulatory listings, not study findings.

8 data sources

Where this comes from

  • EFSA OpenFoodTox

    regulatory · updated 2026-10-04

    Open →

  • EPA Chemical and Products Database

    exposure · updated January 7, 2008

    Open →

  • EPA DSSTox Identifiers

    chemistry · updated 2025-12-29

    Open →

  • FDA Inactive Ingredient Database

    regulatory · updated 2026-01-09

    Open →

  • FDA National Drug Code Directory

    regulatory · updated 2029-06-13

    Open →

  • FDA GSRS UNII

    registry · updated 2026-02-26

    Open →

  • openFDA Substance

    registry · updated 2026-05-24

    Open →

  • PubChem Live Enrichment

    chemistry · updated 2026-05-17

    Open →

Suitability

Context-specific fit derived from published classifications and the current ingredient evidence profile.

Food use

Food-use source coverage is present in the current record.

Good fit

The ingredient appears in food-oriented source coverage or allowed-use references, which makes food use easier to support than a context with no domain signal at all.

Fragrance avoidance

No fragrance-linked caution surfaced in the current profile.

Good fit

This ingredient does not currently read as a fragrance-linked driver in the published evidence and hazard profile.

Where it has been recorded

How often FDA National Drug Code directory has listed Methionine in a product composition. These are source records, not Greenveil catalog products.

Source records

69

Typical roles

FlavouringConditioner
See products using Methionine →

Catalog

Found in these products

Their ingredient lists include Methionine; each product's own rating depends on its whole formula, so it is shown on the product page, not here.

See all 147 →Find products without it →

Co-occurrence

Often appears with

Ingredients that frequently appear alongside Methionine in the catalog.