What it is
In the register’s words: “Keratin Amino Acids is the mixture of amino acids resulting from the complete hydrolysis of Keratin.”
- EU register name (INCI)
- KERATIN AMINO ACIDS
- CAS number
- 65072-01-7 (generic)
What the register lists it for
These are the uses the European Commission’s CosIng register lists for Keratin Amino Acids in any cosmetic, hair roles first. They say why a maker might add it, not what it does in one formula, and they aren’t a safety rating.
- Hair conditioning
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The register’s hair role for ingredients that make hair feel softer, smoother or easier to comb. Most conditioners, masks and leave-ins list several.
Register definition: “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
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A register role for ingredients that help dry or rough skin feel supple again.
Register definition: “Enhancing the appearance of dry and/or damaged skin by reducing flaking and restoring suppleness.”
Where it sits on each label
US labels list ingredients from most to least, except that those at 1% or less may follow in any order. A name near the top is a large part of the formula. A label doesn’t mark where the 1% point falls, so further down, the order says little about how much is in it.
- Rinse-out conditioners 1 label First five names: 0 of 1 Rinse-out conditioners without it
- Protein treatments 1 label First five names: 0 of 1 Protein treatments without it
Every label, product by product (2)
- Ouidad Curl Quencher Moisturizing Conditioner Rinse-out conditioner 16th of 24 names
- Curl Junkie Repair Me! Reconstructive Hair Treatment Protein treatment 7th of 22 names
Each line runs from the first name on a label to the last; a dot is where this ingredient sits. Makers change formulas now and then; if the list on your bottle differs, go by your bottle.
Your next step
Other hair conditioning ingredients on these labels
- Glycerin 131 labels
- Panthenol 72 labels
- Cocos Nucifera (Coconut) Oil 69 labels
- Behentrimonium Methosulfate 38 labels
- Caprylyl Glycol 37 labels
- Behentrimonium Chloride 34 labels
- Cocamidopropyl Betaine 34 labels
- Simmondsia Chinensis (Jojoba) Seed Oil 34 labels
Updated · The name, numbers and uses come from the European Commission’s CosIng entry (CC BY 4.0); we write the uses in US spelling and put the hair ones first. The labels are each maker’s own. The order rule is the FDA’s Cosmetics Labeling Guide. All our sources are on the Sources page.