What function does HYDROXYPROLINE serve in cosmetics?

According to the EU CosIng inventory, HYDROXYPROLINE carries the following function designation(s): ANTISTATIC, HAIR CONDITIONING, SKIN CONDITIONING, SURFACTANT - CLEANSING.

What other records share CAS 51-35-4?

CAS 51-35-4 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 HYDROXYPROLINE?

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 3452515/10/2010

HYDROXYPROLINE

L-4-hydroxyproline

HYDROXYPROLINE 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 51-35-4

CAS 51-35-4PubChem CID 5810

L-Hydroxyproline

Trans-4-hydroxy-L-proline is an optically active form of 4-hydroxyproline having L-trans-configuration. It has a role as a mouse metabolite, a plant metabolite and a human metabolite. It is a tautomer of a trans-4-hydroxy-L-proline zwitterion. — ChEBI

IUPAC name: (2S,4R)-4-hydroxypyrrolidine-2-carboxylic acid

Molecular formula: C5H9NO3
Molecular weight: 131.13 g/mol
Exact mass: 131.058243149 Da
XLogP3: -3.3
Topological polar surface area: 69.6 Å²
Hydrogen-bond donors: 3
Hydrogen-bond acceptors: 4
Covalent units: 1
Defined stereocentres: 2

Also known as

trans-4-Hydroxy-L-prolinehydroxyprolineHyprohydroxy-L-proline(4R)-4-hydroxy-L-prolinetrans-L-HydroxyprolineL-Proline, 4-hydroxy-, (4R)-trans-Hydroxyproline

16 more reported names

4-Hydroxy-2-pyrrolidinecarboxylic aciddelta-HydroxyprolineL-Proline, 4-hydroxy-, trans-(2S,4R)-4-hydroxyprolineRMB44WO89XLUMISTORL-threo-4-hydroxyprolineNSC-46704(2S,4R)-4-hydroxy-2-pyrrolidinecarboxylic acidCHEBI:18095[2S,4R]-4-HYDROXY-2-PYRROLIDINECARBOXYLIC ACIDCHEBI:18240oxyproline(2S,4R)-4-hydroxypyrrolidin-1-ium-2-carboxylateNMH-Procis 4 Hydroxyproline

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:18095
ChEMBL:CHEMBL352418
EPA DTXSID:DTXSID10883225
PubMed:29968805
PubMed:22998630
PubMed:22764742
PubMed:22168216
PubMed:22167201
PubMed:22148719
PubMed:21951102
PubMed:21501141
PubMed:21482820
PubMed:21247092
PubMed:21219648
PubMed:21210682

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 HYDROXYPROLINE

INCI name

HYDROXYPROLINE

Description

L-4-hydroxyproline

Record provenance

Inventory reference: 34525
Imported identity: HYDROXYPROLINE
Source update: 15/10/2010

European Commission CosIng source notes

Annex records for HYDROXYPROLINE

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Key data

CAS

51-35-4

200-091-9

Restriction

—

Function

ANTISTATIC: Preventing and/or reducing static electricity by neutralising electrical charge on surfaces.
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.
SKIN CONDITIONING: Maintaining the skin in good condition.
SURFACTANT - CLEANSING: Wetting body surfaces, emulsifying or solubilizing oils, and suspending soil (generally, such ingredients contribute to the foaming and lathering properties of cleansing products).

Official EU ingredient-name evidence

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

#13325 · HYDROXYPROLINE

Ingredients with overlapping formulation functions

HYDROXYETHYL OLEYL DIMONIUM CHLORIDEANTISTATIC, HAIR CONDITIONING

HYDROXYETHYL STEARAMIDE-MIPAANTISTATIC, OPACIFYING, VISCOSITY CONTROLLING

HYDROXYETHYL TALLOWDIMONIUM CHLORIDEANTISTATIC, HAIR CONDITIONING

HYDROXYLATED LANOLINANTISTATIC, BINDING, FILM FORMING, SKIN CONDITIONING, SKIN CONDITIONING - EMOLLIENT, SURFACTANT - E…

HYDROXYPROPYL ARGININE LAURYL/MYRISTYL ETHER HCLANTISTATIC, HAIR CONDITIONING, SKIN CONDITIONING, SURFACTANT - CLEANSING

HYDROXYPROPYL BISCETEARYLDIMONIUM CHLORIDEANTISTATIC, HAIR CONDITIONING

HYDROXYPROPYL BISISOSTEARAMIDOPROPYLDIMONIUM CHLORIDEANTISTATIC, HAIR CONDITIONING

HYDROXYPROPYL BISOLEYLDIMONIUM CHLORIDEANTISTATIC, HAIR CONDITIONING

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 HYDROXYPROLINE appears in the CosIng inventory

The CosIng inventory lists HYDROXYPROLINE 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.

HYDROXYPROLINE is also tagged with 4 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

HYDROXYPROLINE 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, HYDROXYPROLINE carries the following function designation(s):

CAS 51-35-4 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 HYDROXYPROLINE

This page reproduces the CosIng inventory entry for HYDROXYPROLINE 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 HYDROXYPROLINE 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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