The hydrochloride of the amino acid cysteine, listed as a reducing and hair waving or straightening ingredient.
What it is
Cysteine HCl is cysteine hydrochloride, the hydrochloride salt of cysteine, a sulfur-containing amino acid with a thiol group. CosIng lists it as an antioxidant, hair-conditioning, hair waving or straightening and reducing ingredient.
Where it is used
Appears on the ingredient lists of a small number of products.
Limits of interpretation
The INCI list shows which ingredients are present, not how much of each. Above 1%, ingredients are listed in descending order of weight; below 1% the order is free.
The label does not show the concentration used.
Functions
- Antioxidant
- Inhibiting reactions promoted by oxygen, thus avoiding oxidation and rancidity.
- 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.
- Hair waving or straightening
- Modifying the chemical structure of the hair, allowing it to be set in the style required (permanent waves or hair straightening).
- Reducing
- Changing the chemical nature of another ingredient by adding hydrogen (or removing oxygen).
EU regulation
This ingredient is not listed in the annexes of Regulation (EC) No 1223/2009 in the CosIng data.