Ingredient review
Polyquaternium-78
INCI: Polyquaternium-78
A gentle, modern conditioning polymer that smooths hair and reduces static without the heavy feel of older polyquaterniums.
In plain English
Polyquaternium-78 is a synthetic polymer designed to coat the hair shaft, making it feel softer, smoother, and less prone to frizz or static. Unlike some older conditioning agents, it doesn't build up easily, so hair stays bouncy and clean-looking even after repeated use. It works by forming a thin, flexible film that helps detangle and adds shine.
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
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Polyquaternium-78 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 Polyquaternium-78.
- 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
Polyquaternium-78 is a cationic (positively charged) polymer created through chemical synthesis. It belongs to the polyquaternium family, which are widely used in hair care for their ability to adhere to negatively charged hair fibers and provide conditioning benefits.
How it works
When applied in a rinse-off product like shampoo or conditioner, the positive charge of Polyquaternium-78 binds to the negatively charged surface of damaged or clean hair. This creates an even, thin film that smooths the cuticle, reduces friction between strands, and neutralizes static electricity. The result is easier detangling, less frizz, and a soft, silky feel.
Pros
Lightweight conditioning
Provides smoothness and detangling without the heavy, coated feeling that some older conditioning polymers can leave behind.
Low buildup
Designed to rinse clean more easily than some polyquaterniums, so hair stays fresh and voluminous even with regular use.
Cons and cautions
Limited hold
This polymer is a conditioner, not a styler. It won't provide the hold or structure needed for curls or updos.
Water hardness sensitivity
In very hard water, the polymer may not deposit as evenly, potentially reducing its smoothing benefits.
Best for
- People with frizz-prone or dry hair
- Those who want lightweight conditioning without heavy buildup
Use caution if
- People with very fine or limp hair who prefer zero conditioning agents
- Those with known sensitivity to synthetic polymers (rare)
Usage tips
Safety summary
Polyquaternium-78 is considered safe for use in rinse-off hair products at typical concentrations. It has a low irritation and sensitization potential. As with any ingredient, patch test if you have sensitive skin or a history of reactions to hair products.
Research notes
Published studies and safety reviews indicate that Polyquaternium-78 is a well-tolerated conditioning polymer with low toxicity and irritation potential. Its biodegradability profile is an improvement over some earlier polyquaterniums, though long-term environmental data are still emerging.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and other major markets. No specific concentration restrictions are common at typical use levels.
- Common uses
- Shampoos, Conditioners, Leave-in treatments, Styling products
- Environmental note
- Polyquaternium-78 is designed to be more biodegradable than some older polyquaterniums, though as a synthetic polymer it still requires proper wastewater treatment.
Good to know
- Polyquaternium-78 is often used in sulfate-free shampoos to compensate for the lack of harsh cleansing agents that can strip hair.
- It is considered a more eco-friendly option than some older polyquaterniums because it is designed to be more biodegradable.
Common questions
What is Polyquaternium-78 in beauty products?
Polyquaternium-78 is a synthetic polymer designed to coat the hair shaft, making it feel softer, smoother, and less prone to frizz or static. Unlike some older conditioning agents, it doesn't build up easily, so hair stays bouncy and clean-looking even after repeated use. It works by forming a thin, flexible film that helps detangle and adds shine.
What does Polyquaternium-78 do in a beauty product?
When applied in a rinse-off product like shampoo or conditioner, the positive charge of Polyquaternium-78 binds to the negatively charged surface of damaged or clean hair. This creates an even, thin film that smooths the cuticle, reduces friction between strands, and neutralizes static electricity. The result is easier detangling, less frizz, and a soft, silky feel.
Is Polyquaternium-78 safe for most people?
Polyquaternium-78 is considered safe for use in rinse-off hair products at typical concentrations. It has a low irritation and sensitization potential. As with any ingredient, patch test if you have sensitive skin or a history of reactions to hair products.
Who should be careful with Polyquaternium-78?
People with very fine or limp hair who prefer zero conditioning agents Those with known sensitivity to synthetic polymers (rare)
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.