Ingredient review
Quaternium-79 Hydrolyzed Silk
INCI: Quaternium-79 Hydrolyzed Silk
A gentle conditioning ingredient that helps hair feel soft and smooth while reducing static and flyaways.
In plain English
This ingredient is a modified version of silk protein that has been given a positive electrical charge. In a shampoo or conditioner, that positive charge helps it stick to the negatively charged surface of your hair, forming a thin, smooth film. This film reduces friction, makes hair easier to comb, and helps control frizz and static. On skin, it can leave a silky, non-greasy feel. Because it's derived from natural silk but chemically altered, it's considered semi-synthetic.
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
Quaternium-79 Hydrolyzed Silk 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 Quaternium-79 Hydrolyzed Silk.
- 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 quaternized (positively charged) derivative of hydrolyzed silk protein. The 'quaternium' part means it has a permanent positive charge, which is key for its ability to bind to hair and skin.
How it works
The positive charge on the molecule is attracted to the negative charge on damaged hair and skin. It deposits a thin, protective layer that smooths the cuticle, reduces static electricity, and improves the feeling of softness and slip.
Pros
Excellent detangling
The positive charge helps it bind to hair, reducing friction and making wet combing much easier, which can help prevent breakage.
Low irritation potential
Unlike some harsh quaternary compounds, this silk-derived version is considered very gentle on skin and scalp, making it suitable for sensitive skin.
Cons and cautions
Potential buildup on fine hair
Because it binds strongly, using it too often or in high concentrations can leave a coating that weighs down fine or straight hair over time.
Not vegan-friendly
Silk is produced by silkworms, so this ingredient is not suitable for those following a vegan lifestyle.
Best for
- People with dry, damaged, or frizz-prone hair
- Anyone looking for a gentle, low-irritation conditioner for daily use
Use caution if
- Vegans or those avoiding animal-derived ingredients
Usage tips
Safety summary
Considered safe for use in rinse-off and leave-on products at typical concentrations. It has a low irritation and comedogenic rating, making it suitable for most skin and hair types.
Research notes
While specific studies on Quaternium-79 Hydrolyzed Silk are limited, the safety of quaternized proteins in cosmetics is well-established. The ingredient's function is supported by the general chemistry of cationic surfactants and proteins.
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 beyond general cosmetic safety requirements.
- Common uses
- Shampoos, Conditioners, Leave-in treatments, Serums, Moisturizers
- Environmental note
- Silk production involves silkworm farming, which has a moderate environmental footprint. The quaternization process is a chemical modification that may affect biodegradability.
Good to know
- The 'hydrolyzed' part means the silk protein has been broken down into smaller pieces so it can penetrate the hair shaft slightly and not just sit on the surface.
- This ingredient is often found in 'smoothing' or 'anti-frizz' products.
Common questions
What is Quaternium-79 Hydrolyzed Silk in beauty products?
This ingredient is a modified version of silk protein that has been given a positive electrical charge. In a shampoo or conditioner, that positive charge helps it stick to the negatively charged surface of your hair, forming a thin, smooth film. This film reduces friction, makes hair easier to comb, and helps control frizz and static. On skin, it can leave a silky, non-greasy feel. Because it's derived from natural silk but chemically altered, it's considered semi-synthetic.
What does Quaternium-79 Hydrolyzed Silk do in a beauty product?
The positive charge on the molecule is attracted to the negative charge on damaged hair and skin. It deposits a thin, protective layer that smooths the cuticle, reduces static electricity, and improves the feeling of softness and slip.
Is Quaternium-79 Hydrolyzed Silk safe for most people?
Considered safe for use in rinse-off and leave-on products at typical concentrations. It has a low irritation and comedogenic rating, making it suitable for most skin and hair types.
Who should be careful with Quaternium-79 Hydrolyzed Silk?
Vegans or those avoiding animal-derived 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.