What Is Polyquaternium-115?
Polyquaternium-115 is a positively charged polymer made from three building blocks: acrylamide, ethylhexyl acrylate and methacryloyloxyethyltrimonium chloride. Chemists combine these small units in a water-based reaction called free radical polymerization, creating long chains that stay dissolved in the final formula. The result is a clear to slightly hazy liquid that mixes well with water and most common cosmetic ingredients.
Quaternary ammonium polymers, often shortened to “quats,” first appeared in hair lotions in the 1950s for their softening effect. Over time, companies looked for quats that were gentler, more flexible and better at clinging to damaged hair and skin. Polyquaternium-115 is one of these newer options and has been on the market since the early 2000s.
You will usually find Polyquaternium-115 in rinse-off and leave-on hair products such as shampoos, daily conditioners, deep masks, detangling sprays and styling creams. Skin care lines also use it in light moisturizers, aftershave balms, body lotions and hand creams where a smooth, non-greasy feel is desired.
Polyquaternium-115’s Cosmetic Benefits/Uses
This ingredient offers two main benefits to both hair and skin formulas
- Hair conditioning – The positive charge in Polyquaternium-115 is attracted to the negative sites on damaged hair. It forms a thin film that smooths the cuticle, reduces static and makes hair easier to comb wet or dry. The film also helps lock in moisture so strands feel softer and look shinier.
- Skin conditioning – On the skin, the same light film improves slip during application and leaves a silky finish once the product is absorbed. It can lessen the tight feeling some people get after washing and adds a mild protective layer that helps skin stay hydrated throughout the day.
Who Can Use Polyquaternium-115
Polyquaternium-115 is gentle enough for all skin and hair types. Dry, rough or chemically treated hair will see the biggest boost in softness and shine while normal and oily scalps can still use it because the polymer rinses clean without leaving a greasy feel. On skin, its lightweight film works well for dry, normal and combination types and it does not clog pores so acne-prone users can typically enjoy it too.
The ingredient is made by reacting simple petrochemical-derived monomers in water, with no animal by-products involved, which means it is suitable for vegans and vegetarians.
No studies show that Polyquaternium-115 is harmful to people who are pregnant or breastfeeding when used in rinse-off or leave-on cosmetic levels. This is not medical advice and anyone who is expecting or nursing should show the full ingredient list of any personal care product to their doctor to be extra careful.
Polyquaternium-115 does not absorb UV light or make skin more sensitive to the sun, so there is no added risk of photosensitivity.
Potential Side Effects/Adverse Reactions
Reactions to any cosmetic ingredient can differ from person to person. The issues listed below are only potential side effects and are not expected for most users when the product is well formulated and used as directed.
- Mild scalp or skin irritation
- Transient redness in very sensitive skin
- Eye stinging if the product accidentally gets into the eyes
- Rare allergic contact dermatitis
If you notice burning, swelling or a persistent rash after using a product that contains Polyquaternium-115 stop using it and consult a healthcare professional.
Comedogenic Rating
Rating: 0–1 (very low)
Polyquaternium-115 is a large, water-soluble polymer that forms a thin breathable film rather than an oily layer. Because it does not sit heavy on the skin or block pores, it is considered non-comedogenic or at worst very low on the scale.
That means most people who are prone to acne or breakouts can use products containing Polyquaternium-115 without extra worry.
Keep in mind the final product formula matters too. Heavy oils, waxes or fragrances paired with the polymer could still trigger breakouts even if Polyquaternium-115 itself is not the culprit.
Summary
Polyquaternium-115 works mainly as a hair and skin conditioner. Its positive charge lets it cling to the negatively charged spots on damaged hair and dry skin, laying down a light film that smooths cuticles, cuts static, boosts slip and helps lock in moisture. The result is softer, shinier hair and skin that feels silky, not greasy.
While not as famous as some older quats like Polyquaternium-10, this ingredient shows up in a steady stream of modern shampoos, conditioners, leave-ins and lightweight lotions because formulators like its gentle feel and rinse-clean finish.
Safety reviews and years of use point to a very low risk of irritation or toxicity when used at normal cosmetic levels. Still, everyone’s skin is unique, so it is smart to patch test any new product that contains Polyquaternium-115 before full use.