PG-Hydrolyzed Silk

INCI: PG-Hydrolyzed Silk | Function: Skin Conditioning, Film Former, Humectant | Type: Protein derivative (PG-modified hydrolyzed silk fibroin)

What Is PG-Hydrolyzed Silk?

PG-modified hydrolyzed silk fibroin — silk protein (from Bombyx mori cocoons) broken into peptides and esterified with propylene glycol. Silk fibroin is rich in glycine, alanine, and serine, providing a uniquely smooth, silky feel. The PG modification enhances water solubility and prevents the gelling issues common with unmodified silk proteins.

Key Skin Benefits

+ Luxurious silky feel — signature sensory profile of silk proteins
+ Film-forming — creates a smooth, breathable protective film
+ Moisture retention — silk peptides help maintain skin hydration
+ Hair conditioning — adds shine and smoothness to hair

Pros

+ Premium sensory experience — distinctive silky after-feel
+ Rich in glycine and alanine — amino acids that support skin
+ PG modification prevents the stickiness of plain silk protein
+ Good for luxury/high-end product positioning

Cons

− Animal-derived — not vegan (silk from silkworms)
− Higher cost than plant protein alternatives
− Some consumers avoid insect-derived ingredients
− Limited sustainability — silk production has environmental impacts

Specifications

Property	Value
Usage Areas	Face, Body, 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	1/10

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 %
Luxury serum	0.5–3%
Premium 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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