PEG-6 Stearylguanidine is a cationic surfactant with a guanidine functional group attached to a stearyl chain via a PEG-6 spacer. The guanidine group is highly basic and provides strong substantivity to hair. It functions as a conditioning agent and antistatic agent, primarily in hair care products.
Key Skin Benefits
+ Strong conditioning — guanidine group provides excellent hair affinity
+ Antistatic — reduces static charge effectively
+ Wet combing — improves ease of combing wet hair
Pros
+ Stronger binding to hair than simple quaternary ammonium compounds
+ Effective at very low concentrations (0.2-1%)
+ Improves hair strength and reduces breakage
Cons
− Synthetic origin
− Rarely used — limited safety data compared to common quats
− Guanidine derivatives can be irritating at high levels
Specifications
Property
Value
Usage Areas
Hair
Product Type
Rinse-Off
Source
Synthetic
Natural Level
Synthetic
Safety Ratings
Metric
Rating
Skin Sensitivity
2/5
Comedogenic Rating
1/5
EWG Score
3/10
Regional Regulatory Limits
Region
Leave-on %
Rinse-off %
Status
EU (CosIng)
No limit
No limit
Allowed
US (CIR/FDA)
No limit
No limit
Allowed
Japan (MHLW)
No limit
No limit
Allowed
ASEAN
No limit
No limit
Allowed
China (NMPA)
No limit
No limit
Allowed
Typical Usage % by Product Type
Product Type
Typical %
Conditioners
0.2 - 1%
Shampoos
0.2 - 0.8%
Hair masks
0.5 - 1.5%
References
CIR (2010) — Safety Assessment of PEGs. https://www.cir-safety.org/
CosIng (2025) — European Commission Cosmetic Ingredient Database. https://ec.europa.eu/growth/tools-databases/cosing/