What Is Polyquaternium-64?
Polyquaternium-64 is a man-made polymer built from quaternary ammonium units. Chemically it combines 2-methyl-2-propenoyloxyethyl N,N,N-trimethylammonioethyl phosphate inner salt with 2-hydroxy-3-(2-methyl-2-propenoyl)oxypropyltrimethylammonium chloride, creating a long chain that holds a positive charge. That charge is what makes the ingredient so useful in hair care. It is derived through controlled laboratory reactions rather than from a natural plant or animal source. Developers first explored these charged polymers in the late 1970s while searching for milder alternatives to traditional hair fixatives. Over time formulators noticed that Polyquaternium-64 could smooth the hair surface without leaving a heavy buildup, leading to its wider adoption in shampoos and conditioners during the 1990s.
The production process starts with acrylic or methacrylic monomers that carry quaternary ammonium groups. These monomers are mixed in water, then polymerized under heat and gentle stirring until they link into a clear, viscous solution. After purification and pH adjustment the ingredient is ready for cosmetic use. Because it is water soluble it blends easily into both rinse-off and leave-on formulas.
You will most often spot Polyquaternium-64 in shampoos, rinse-out and leave-in conditioners, hair masks, styling creams and color-protecting treatments. A few skin care serums also include it for a light conditioning feel, though its main stage remains hair care.
Polyquaternium-64’s Cosmetic Benefits/Uses
Formulators reach for Polyquaternium-64 when they want soft, manageable hair without a greasy after-feel.
As a hair conditioning agent Polyquaternium-64 clings to the negatively charged surface of hair fibers, forming an even film that smooths cuticles, reduces static flyaways and improves combing on both wet and dry strands. This film helps lock in moisture so hair feels softer and looks shinier. Because the polymer is water soluble it rinses cleanly, so it conditions without weighing fine hair down or causing noticeable buildup over time.
Who Can Use Polyquaternium-64
Polyquaternium-64 is considered suitable for all hair and skin types, including oily, dry, and sensitive scalps. Because it is water soluble and rinses cleanly it rarely weighs down fine hair or leaves residue on oily scalps. Those with extremely sensitive skin can still benefit, though it is wise to monitor for any personal sensitivities, as with any new ingredient.
The polymer is synthesized entirely from laboratory chemicals rather than animal sources so it aligns with vegan and vegetarian lifestyles. No animal by-products are used during manufacture or purification.
Current safety data show no special restrictions for use during pregnancy or while breastfeeding. That said this information is not medical advice and anyone who is pregnant or nursing should run any new personal care product past a qualified health professional to be on the safe side.
Polyquaternium-64 does not increase photosensitivity. Users do not need extra sun protection beyond normal daily sunscreen recommendations.
Potential Side Effects/Adverse Reactions
Reactions to topical Polyquaternium-64 vary from person to person. The issues listed below are only potential effects and are not likely to occur for most people when the ingredient is formulated and used as intended.
- Mild scalp or skin irritation such as redness or itching
- Allergic contact dermatitis in individuals sensitive to quaternary ammonium compounds
- Eye irritation if the product accidentally gets into the eyes
- Temporary limp or weighed-down feel on very fine hair when over applied
If any adverse reaction develops stop using the product immediately and seek guidance from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0–1 (essentially non-comedogenic)
Polyquaternium-64 is a large, water-soluble polymer that sits on the hair or skin surface and rinses away easily. It does not contain heavy oils or waxes that can block pores, so it is very unlikely to trigger blackheads or pimples. Because it carries a positive charge it is attracted to hair rather than skin’s oil ducts, further lowering clogging risk.
For people prone to acne or frequent breakouts this ingredient is generally considered safe to use.
No studies link Polyquaternium-64 to fungal acne flare-ups either, making it a low-risk choice across most skin concerns.
Summary
Polyquaternium-64 is a synthetic, water-loving polymer that conditions hair by forming a light film, smoothing cuticles, cutting static and helping strands hold moisture. Its positive charge lets it bind to negatively charged hair surfaces, then rinse away without leaving a greasy feel. You will spot it in shampoos, conditioners, masks and a few lightweight skin products.
The ingredient enjoys steady use in mainstream hair care but is not as famous as silicone or protein treatments. Formulators like it because it is easy to add to water-based products and delivers softness without weighing hair down.
Overall safety data are strong, with irritation or allergy being rare. While it is generally gentle, it is smart to patch test any new product to confirm personal compatibility.