Ingredient review
Hydrolyzed Silk Crosspolymer
INCI: Hydrolyzed Silk PG-Propyl Methylsilanediol Crosspolymer
A gentle film-forming ingredient derived from silk that helps smooth and protect skin and hair without heavy residue.
In plain English
This ingredient is a modified version of silk protein that has been chemically linked to a silicone-like molecule. It spreads easily over skin or hair and dries down into an invisible, flexible film. That film helps lock in moisture, smooth rough texture, and add a soft, silky feel without being sticky or greasy. It is often used in leave-on products like serums and conditioners.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Hydrolyzed Silk Crosspolymer is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Hydrolyzed Silk Crosspolymer.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A semi-synthetic polymer created by combining hydrolyzed silk protein with a silicone-based crosslinker (PG-propyl methylsilanediol). This gives it both the amino-acid benefits of silk and the film-forming, smooth feel of silicones.
How it works
When applied, the crosspolymer forms a thin, breathable film on the surface of the skin or hair. This film reduces water loss, smooths the cuticle, and provides a soft, silky slip. Unlike pure silicones, it is more water-friendly and less likely to build up over time.
Pros
Lightweight silky feel
Unlike many silicones, this crosspolymer leaves a soft, non-greasy finish that doesn't weigh down hair or clog pores.
Breathable film
The film it forms allows moisture to escape while still protecting the surface, reducing the risk of buildup or irritation.
Cons and cautions
Semi-synthetic origin
Because it is chemically modified, it may not appeal to consumers seeking fully natural or 'clean' ingredients.
Potential buildup on fine hair
In high concentrations or with frequent use, it could cause slight buildup on very fine or low-porosity hair, leading to limpness.
Best for
- Anyone wanting a smooth, silky finish without heavy silicones
- People with dry or damaged hair looking for frizz control
- Those who enjoy lightweight, breathable skin protection
Use caution if
- Those strictly avoiding any silicone-derived ingredients
- Individuals with very fine hair who prefer zero film-forming ingredients
Usage tips
Safety summary
Considered safe for topical use in cosmetics. Low irritation and comedogenic potential. No known significant safety concerns from regulatory bodies.
Research notes
Limited peer-reviewed studies specifically on this crosspolymer, but its components (hydrolyzed silk and silicone derivatives) have a long history of safe use. Evidence is based on formulation experience and ingredient safety assessments.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and most major markets. No specific restrictions.
- Common uses
- Serums, Moisturizers, Hair conditioners, Leave-in treatments, Styling products
- Environmental note
- As a semi-synthetic polymer, its biodegradability is not fully established. It is not known to be a major environmental concern at typical usage levels.
Good to know
- This ingredient is often listed near the end of an ingredient list because it is used at low concentrations.
- It is water-soluble and rinses out more easily than many traditional silicones.
Common questions
What is Hydrolyzed Silk Crosspolymer in beauty products?
This ingredient is a modified version of silk protein that has been chemically linked to a silicone-like molecule. It spreads easily over skin or hair and dries down into an invisible, flexible film. That film helps lock in moisture, smooth rough texture, and add a soft, silky feel without being sticky or greasy. It is often used in leave-on products like serums and conditioners.
What does Hydrolyzed Silk Crosspolymer do in a beauty product?
When applied, the crosspolymer forms a thin, breathable film on the surface of the skin or hair. This film reduces water loss, smooths the cuticle, and provides a soft, silky slip. Unlike pure silicones, it is more water-friendly and less likely to build up over time.
Is Hydrolyzed Silk Crosspolymer safe for most people?
Considered safe for topical use in cosmetics. Low irritation and comedogenic potential. No known significant safety concerns from regulatory bodies.
Who should be careful with Hydrolyzed Silk Crosspolymer?
Those strictly avoiding any silicone-derived ingredients Individuals with very fine hair who prefer zero film-forming ingredients
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.