PG-Hydrolyzed Keratin

INCI: PG-Hydrolyzed Keratin | Function: Hair Conditioning, Film Former, Humectant | Type: Protein derivative (PG-modified hydrolyzed keratin)

What Is PG-Hydrolyzed Keratin?

Propylene glycol-modified hydrolyzed keratin — wool or feather keratin broken into peptides and esterified with PG. The PG modification improves water solubility and film flexibility. Used in hair care for its affinity to hair keratin — helps fill in damaged cuticle gaps and provides strengthening and smoothing effects.

Key Skin Benefits

+ Hair strengthening — keratin peptides bond to damaged hair structure
+ Smoothing — fills cuticle gaps for reduced frizz
+ Film-forming — provides heat protection and style hold
+ Improved solubility — PG modification prevents precipitation

Pros

+ Structurally similar to hair keratin — high affinity
+ PG modification improves formulation compatibility
+ Effective for chemically damaged/bleached hair repair
+ Good heat protection properties

Cons

− Animal-derived — not vegan (wool keratin) or may use feather keratin
− Keratin peptides are large — limited skin penetration
− Can build up on hair with excessive use
− May contain residual processing chemicals

Specifications

Property	Value
Usage Areas	Hair
Product Type	Leave-On, Rinse-Off
Source	Animal
Natural Level	Semi-synthetic

Safety Ratings

Metric	Rating
Skin Sensitivity	0-1/5 (very low)
Comedogenic Rating	0/5
EWG Score	2/10

Regional Regulatory Limits

Region	Leave-on %	Rinse-off %	Status
EU (CosIng)	No limit	No limit	Allowed
US (CIR/FDA)	No limit	No limit	Allowed — CIR safe as used
Japan (MHLW)	No limit	No limit	Allowed
ASEAN	No limit	No limit	Allowed — follows EU
China (NMPA)	No limit	No limit	Allowed — listed in IECIC

Typical Usage % by Product Type

Product Type	Typical %
Hair mask / treatment	0.5–5%
Leave-in conditioner	0.5–3%

References

CIR Safety Assessment. https://www.cir-safety.org/
EU CosIng Database. https://ec.europa.eu/growth/tools-databases/cosing/
EWG Skin Deep Database. https://www.ewg.org/skindeep/
SpecialChem Cosmetic Ingredients. https://cosmetics.specialchem.com/

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