Ingredient review
Polyquaternium-37
INCI: Polyquaternium-37
A gentle synthetic polymer that smooths hair and skin without heavy buildup, ideal for sensitive scalps.
In plain English
Polyquaternium-37 is a man-made ingredient that forms a thin, flexible film on hair or skin. This film helps reduce frizz, adds slip, and makes hair easier to comb. It also helps other ingredients spread evenly and stay put. Because it's water-soluble, it rinses off easily and doesn't leave a sticky or greasy feeling.
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-37 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-37.
- 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 positively charged synthetic polymer (a type of plastic-like molecule) designed to cling to negatively charged surfaces like hair and skin.
How it works
Its positive charge attracts it to the negative charge of damaged hair or skin, forming a smooth, protective layer. This layer reduces friction, prevents static, and locks in moisture.
Pros
Gentle on sensitive skin
Polyquaternium-37 is considered low-irritation and safe for most skin types, including sensitive scalps.
Lightweight conditioning
It provides smoothness and slip without the heavy, greasy feel of some oils or silicones.
Cons and cautions
Potential buildup
With daily use on fine hair, it can accumulate slightly, requiring a clarifying shampoo every few weeks.
Synthetic origin
It is not natural or biodegradable, which may be a concern for eco-conscious consumers.
Best for
- Anyone with frizzy or dry hair
- People with sensitive scalps who want a gentle conditioner
Use caution if
- Those who prefer completely natural or biodegradable ingredients
- Individuals with very fine hair who may experience slight buildup
Usage tips
Safety summary
Polyquaternium-37 has a strong safety profile with low irritation and sensitization potential. It is well-tolerated even on sensitive skin and scalps.
Research notes
Studies confirm its low toxicity and skin compatibility. It is widely used in personal care with no significant safety concerns reported in peer-reviewed literature.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. No known restrictions at typical use levels.
- Common uses
- Conditioners, Styling products, Leave-in treatments
- Environmental note
- As a synthetic polymer, it is not readily biodegradable. However, it is used in low concentrations and is generally considered safe for aquatic life at those levels.
Good to know
- Polyquaternium-37 is often used in combination with other polymers to fine-tune texture and hold.
- It is approved for use in cosmetics globally, including by the EU and FDA.
Common questions
What is Polyquaternium-37 in beauty products?
Polyquaternium-37 is a man-made ingredient that forms a thin, flexible film on hair or skin. This film helps reduce frizz, adds slip, and makes hair easier to comb. It also helps other ingredients spread evenly and stay put. Because it's water-soluble, it rinses off easily and doesn't leave a sticky or greasy feeling.
What does Polyquaternium-37 do in a beauty product?
Its positive charge attracts it to the negative charge of damaged hair or skin, forming a smooth, protective layer. This layer reduces friction, prevents static, and locks in moisture.
Is Polyquaternium-37 safe for most people?
Polyquaternium-37 has a strong safety profile with low irritation and sensitization potential. It is well-tolerated even on sensitive skin and scalps.
Who should be careful with Polyquaternium-37?
Those who prefer completely natural or biodegradable ingredients Individuals with very fine hair who may experience slight buildup
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.