Cysteine
A cosmetic ingredient used as antioxidant, antistatic, fragrance in skincare, haircare, and personal-care products sold in the European Union.
What is it?
L-Cysteine
What does it do?
Cysteine is listed in the EU cosmetic ingredient inventory with the following declared functions:
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Antioxidant
neutralises free radicals to slow oxidative damage to the formulation or skin
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Antistatic
reduces static electricity, mostly in hair products to keep strands smooth and manageable
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Fragrance
provides scent or masks the natural odour of other ingredients
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Hair conditioning
improves the appearance, feel, and manageability of hair
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Hair waving or straightening
permanently changes the shape of hair through chemical reduction and re-oxidation of the hair's disulfide bonds
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Reducing
a reducing agent — donates electrons to break chemical bonds, used in perms and depilatories
EU regulatory status
Cysteine is allowed for use in cosmetic products in the European Union under Regulation 1223/2009. It is not subject to a specific Annex restriction at the time of writing.
Frequently asked questions
What is Cysteine?
Cysteine is a cosmetic ingredient catalogued in the EU CosIng database. L-Cysteine
Is Cysteine allowed in cosmetics in the EU?
Yes. Cysteine is allowed for use in cosmetic products in the EU under Regulation 1223/2009.
What does Cysteine do in cosmetic products?
Cysteine is declared in the EU cosmetic ingredient inventory with these functions: antioxidant, antistatic, fragrance, hair conditioning, hair waving or straightening, reducing.
What is the CAS number of Cysteine?
The CAS (Chemical Abstracts Service) number for Cysteine is 52-90-4 / 3374-22-9.
Related ingredients
Source: EU CosIng database (European Commission). This page is derived from public-sector information published by the European Commission. · Last updated: 15/10/2010