What Is Polyquaternium-73?
Polyquaternium-73 is a man-made polymer that belongs to the family of quaternary ammonium compounds, often shortened to “quats.” It is built from three different monomers: propyltrimonium chloride acrylamide, ethyltrimonium chloride methacrylate and dimethylacrylamide. When these charged building blocks are linked together through a controlled water-based reaction called polymerization they form a flexible, clear film-forming ingredient that carries a positive charge. Because the molecule is synthetic it is not harvested from plants or animals, giving formulators a consistent raw material with predictable performance.
Quats have been popular in hair care since the 1970s for their ability to fight static and improve comb-through. Polyquaternium-73 is one of the newer members of this large group, gaining attention in the early 2000s when chemists wanted a version that could fix hair styles yet still rinse out easily. Its balanced charge density and medium molecular weight met those needs, so it started to show up first in salon styling sprays then in mass-market conditioners.
Production begins with three liquid monomers that are each quaternized, meaning they already carry a permanent positive charge. They are mixed in precise ratios then exposed to heat and a small amount of initiator that starts the polymer chain reaction. Once the desired chain length is reached the mixture is cooled, filtered and standardized into either a clear aqueous solution or a dry powder.
Today you can find Polyquaternium-73 in hair sprays, styling gels, mousses, curl creams, leave-in conditioners, rinse-off conditioners, hair masks and anti-frizz serums. It is also used in a few skin care formulas such as peel-off masks and long-wear primers where a light, flexible film is helpful.
Polyquaternium-73’s Cosmetic Benefits/Uses
Below are the main ways this ingredient works inside a formula
- Antistatic – The positive charge neutralizes the negative charge that builds up on hair strands during brushing or blow drying which cuts down on flyaways and static cling
- Film Forming – It creates an invisible, breathable layer on the hair or skin surface that locks in moisture and protects against humidity, pollution and light physical damage
- Hair Conditioning – The polymer smooths the cuticle, improves slip and makes wet and dry combing easier so hair feels softer and looks shinier
- Hair Fixing – By forming a flexible network it helps set styles, boost curl retention and provide light to medium hold without the stiffness some traditional resins cause
Who Can Use Polyquaternium-73
Polyquaternium-73 is generally considered suitable for all skin and scalp types, including dry, oily, combination and even sensitive conditions. Its mild, nonpenetrating film stays on the surface so it rarely disrupts the skin barrier or hair cuticle. People with very sensitive or compromised skin may still want to watch for any stinging or redness simply because any leave-on film can sometimes trap irritants underneath.
The ingredient is fully synthetic and is not sourced from animals, making it appropriate for vegans and vegetarians. It is also not inherently tied to animal testing, although final cruelty-free status depends on the end brand’s policies and regional regulations.
No published data links Polyquaternium-73 to problems during pregnancy or breastfeeding. It is not known to be absorbed into the bloodstream at meaningful levels, so normal topical use in hair or skin products is viewed as low risk. This is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of any product to their healthcare provider before use just to be safe.
Polyquaternium-73 does not make skin more sensitive to sunlight and it does not interfere with sunscreen efficacy, so there is no special need for extra sun protection beyond normal daily habits.
Because the polymer rinses away with shampoo and most face cleansers, it is also acceptable for people following low-build-up or “curly girl” hair routines when used in moderation.
Potential Side Effects/Adverse Reactions
Reactions to topical Polyquaternium-73 vary from person to person. The points below list potential side effects that could occur, but most users will never experience them when the ingredient is used correctly in a well-formulated product.
- Mild scalp or skin irritation such as itching or redness, usually linked to overuse or existing sensitivity to cationic polymers
- Allergic contact dermatitis in rare cases where an individual is allergic to quaternary ammonium compounds
- Product buildup leading to dull, heavy hair if cleansing is inadequate, especially on very fine or low porosity hair
- Eye irritation if the product accidentally gets into the eyes, causing stinging or watering
- Flaking or white residue when combined with high levels of anionic surfactants that can cause the polymer to precipitate on the hair shaft
If any adverse reaction occurs stop using the product immediately and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0 (non comedogenic)
Polyquaternium-73 is a large, positively charged polymer that stays on the surface of skin and hair then rinses away with water and mild cleansers. It is water soluble, does not sink into pores and shows no evidence of trapping sebum or dead cells, which is why it earns the lowest comedogenic score.
Suitable for acne-prone and breakout-prone skin.
Because it is often paired with heavier oils or waxes in styling products, any clogged pore issues are usually linked to those co-ingredients rather than Polyquaternium-73 itself.
Summary
Polyquaternium-73 works as an antistatic, film former, hair conditioner and light hold fixer. Its positive charge adheres to negatively charged hair fibers, smoothing the cuticle and cutting flyaways while the flexible film keeps styles in place and shields strands from humidity and pollution.
Although not as famous as silicone classics or newer plant proteins it has carved out a steady niche in salon sprays, mousses and leave-in conditioners thanks to its reliable performance and easy rinse-off.
Current safety data show low irritation potential, minimal absorption and no comedogenicity, making it generally safe for everyday use on skin and hair. As with any new product it is wise to do a quick patch test to confirm personal tolerance.