Is CYSTINE safe to use in EU cosmetics?

CYSTINE is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Always verify against the current official CosIng database before formulating.

What other records share CAS 56-89-3?

CAS 56-89-3 may appear across multiple EU annex records. The CAS lookup page shows all Annex II–VI entries sharing this identifier, useful for identifying cross-annex regulatory status of the same chemical substance.

How do I check if my formula contains CYSTINE?

Use the INCI Checker to screen a full ingredient list across selected markets, or use the substance market comparison to review this identity across all supported market datasets.

InventoryRef 7542415/10/2010

CYSTINE

Cystine

CYSTINE is listed in the EU CosIng inventory, but no direct annex records are linked on this page yet.

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Regulatory evidence by market

No rule for this ingredient has been imported for any of the 13 markets tracked here.

That describes this inventory, not the law. No imported rule is not evidence that an ingredient is permitted: a rule may exist under another name or identifier, or in a dataset not yet imported here.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 56-89-3

CAS 56-89-3PubChem CID 67678

(-)-Cystine

L-cystine is the L-enantiomer of the sulfur-containing amino acid cystine. It has a role as an EC 1.2.1.11 (aspartate-semialdehyde dehydrogenase) inhibitor, a flour treatment agent, a mouse metabolite, a Saccharomyces cerevisiae metabolite and a human metabolite. It is a cystine, a non-proteinogenic L-alpha-amino acid and a L-cysteine derivative. It is a conjugate acid of a L-cystine anion. It is an enantiomer of a D-cystine. It is a tautomer of a L-cystine zwitterion. — ChEBI

IUPAC name: (2R)-2-amino-3-[[(2R)-2-amino-2-carboxyethyl]disulfanyl]propanoic acid

Molecular formula: C6H12N2O4S2
Molecular weight: 240.3 g/mol
Exact mass: 240.02384922 Da
XLogP3: -6.3
Topological polar surface area: 177.0 Å²
Hydrogen-bond donors: 4
Hydrogen-bond acceptors: 8
Covalent units: 1
Defined stereocentres: 2

Also known as

L-cystinecystineL-Dicysteinebeta,beta'-DithiodialanineL-Cysteine disulfide1-CystineCystine, L-Dicysteine

16 more reported names

Cystine (L)-Cystine acidCysteine disulfideCystinAlanine, 3,3'-dithiodi-Alanine, 3,3'-dithiobis-beta,beta'-Dithioalanine, L-L-Alanine, 3,3'-dithiobis-L-alpha-Diamino-beta-dithiolactic acid3,3'-Dithiobis(2-aminopropanoic acid)3,3'-DithiodialaninecistinaBis(beta-amino-beta-carboxyethyl)disulfide(R-(R*,R*))-3,3'-Dithiobis(2-aminopropanoic acid)48TCX9A1VTbeta,beta'-Diamino-beta,beta'-dicarboxydiethyl disulfide

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:16283
ChEMBL:CHEMBL590540
EPA DTXSID:DTXSID2046418
PubMed:35204234
PubMed:22675475
PubMed:22561356
PubMed:22548128
PubMed:22291693
PubMed:22230336
PubMed:22216172
PubMed:22145046
PubMed:22093698
PubMed:21801426
PubMed:21714924
PubMed:21699715

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Inventory details for CYSTINE

INCI name

CYSTINE

INN name

cystine

Description

Cystine

Record provenance

Inventory reference: 75424
Imported identity: CYSTINE
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for CYSTINE

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Key data

CAS

56-89-3

200-296-3

Restriction

—

Function

ANTISTATIC: Preventing and/or reducing static electricity by neutralising electrical charge on surfaces.
FRAGRANCE: Imparting an odour or taste. Creating a perceivable pleasant smell and/or masking a bad smell.
HAIR CONDITIONING: Enhancing the appearance and feel of hair. Leaving the hair easy to comb, supple, soft and shiny and/or imparting volume, lightness, gloss, texture, etc.

Official EU ingredient-name evidence

The ingredient name exactly matches the official 2025 EU glossary of common ingredient names.

#7984 · CYSTINE

Ingredients with overlapping formulation functions

COCOYL HYDROXYETHYLIMIDAZOLINIUM PG-CHLORIDE PHOSPHATEANTISTATIC, HAIR CONDITIONING

COCOYL POLYGLYCERYL-4 HYDROXYPROPYL DIHYDROXYETHYLAMINEANTISTATIC

CORN STARCH/ACRYLAMIDE/SODIUM ACRYLATE COPOLYMERANTISTATIC, FILM FORMING, HAIR CONDITIONING, HAIR FIXING, LIGHT STABILIZER

CYSTEINEANTIOXIDANT, ANTISTATIC, FRAGRANCE, HAIR CONDITIONING, HAIR WAVING OR STRAIGHTENING, REDUCING

DEA-LAURAMINOPROPIONATEANTISTATIC, HAIR CONDITIONING

DEA-LINOLEATEANTISTATIC, SURFACTANT - EMULSIFYING, VISCOSITY CONTROLLING

DECARBOXY CARNOSINE HCLANTISTATIC, HAIR CONDITIONING, SKIN CONDITIONING

DECYL BETAINEANTISTATIC, CLEANSING, HAIR CONDITIONING, SKIN CONDITIONING, SURFACTANT - CLEANSING, SURFACTANT - F…

Additional official and scientific sources

11 external databases to check this identity in

Each link searches that source for this identity. What each source is, and its legal weight

ECHA CHEM / Information on chemicals PubChem PUG REST EU Safety Gate cosmetic product alerts ECHA CHEM US EPA CompTox Cosmetic Ingredient Review safety assessments FDA Global Substance Registration System ILO/WHO International Chemical Safety Cards Japan NITE-CHRIP NIOSH Pocket Guide to Chemical Hazards OECD eChemPortal

How CYSTINE appears in the CosIng inventory

The CosIng inventory lists CYSTINE as a cosmetic ingredient and this page links it to 0 annex records. The inventory entry captures names and identifiers, while the annex records show where the substance is prohibited, restricted or positively listed in EU cosmetics law.

CYSTINE is also tagged with 3 cosmetic functions in the official data. Function labels describe intended use, but they do not replace regulatory review of linked annex records before formulation or labelling work.

Frequently asked questions

CYSTINE is listed in the EU CosIng ingredient inventory with no direct annex restriction records linked at this time. Absence of an annex link does not guarantee unrestricted use — always verify against the current official CosIng database before formulating.

According to the EU CosIng inventory, CYSTINE carries the following function designation(s):

CAS 56-89-3 may appear across multiple EU annex records. Viewing the CAS lookup page shows all Annex II–VI entries sharing this identifier, which is useful for identifying cross-annex regulatory status of the same chemical substance.

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Source note for CYSTINE

This page reproduces the CosIng inventory entry for CYSTINE from public European Commission cosmetic ingredient materials and shows linked identifiers even when no direct annex match is currently attached.

Use this inventory page to research CYSTINE and compare linked records, but verify restrictions and legal status against the current official source text and law before making regulatory decisions.

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