What Is Polyquaternium-70?
Polyquaternium-70 is a synthetic conditioning agent made by linking together fatty amines derived from stearyl alcohol, adding small units of ethylene oxide and propylene oxide, then joining the chain to adipic acid and dilinoleic acid before giving it a positive charge with dimethyl sulfate. This positive charge helps it cling to negatively charged hair strands. The ingredient first appeared in the late 1990s when formulators were looking for gentler alternatives to traditional conditioning quats that could work in water based products without weighing hair down. Today manufacturers create Polyquaternium-70 in a controlled, closed system reactor where temperature and pH are carefully monitored, followed by purification and spray-drying to form a fine powder or aqueous solution ready for use in cosmetics. You will most often see it in rinse-off and leave-in conditioners, masks, anti-frizz creams, styling gels, 2-in-1 shampoos and color protection treatments.
Polyquaternium-70’s Cosmetic Benefits/Uses
In formulas Polyquaternium-70 serves one main purpose that delivers several perks for hair care products.
Hair conditioning: Its positive charge attracts it to the damaged, negatively charged spots along the hair cuticle, forming a thin, even film that smooths the surface, reduces static, boosts softness, makes detangling easier and helps hair look shinier and healthier.
Who Can Use Polyquaternium-70
Polyquaternium-70 is considered suitable for all scalp and hair types, including dry, oily, color treated and chemically processed hair. Its film forming action is lightweight, so it rarely weighs down fine strands and the cationic charge helps smooth coarse or damaged hair without leaving a greasy feel. People with very sensitive scalps can usually tolerate it because it is non reactive and does not penetrate skin, though anyone with a known quaternary ammonium allergy should avoid it.
The ingredient is produced synthetically and the stearyl alcohol used today is typically sourced from coconut or palm oils, not animal fat, making most commercial grades acceptable for vegans and vegetarians. Those who follow a strict lifestyle should still verify the raw material origin with the brand.
Current safety data indicate no reproductive or developmental concerns, so products containing Polyquaternium-70 are generally viewed as safe for women who are pregnant or breastfeeding. That said, this is not medical advice and pregnant or nursing consumers should run any new hair care product past their doctor just to be on the safe side.
Polyquaternium-70 does not cause photosensitivity and it has no known interactions with common hair dyes, relaxers or keratin treatments.
Potential Side Effects/Adverse Reactions
Reactions to topical Polyquaternium-70 vary from person to person. The effects listed below are possible but uncommon when the ingredient is used at normal cosmetic levels and formulated correctly.
- Mild scalp irritation – a temporary tingling or redness that usually subsides after rinsing
- Allergic contact dermatitis – rare itchiness or rash in individuals sensitive to quaternary ammonium compounds
- Product build-up – repeated use without clarifying shampoo may leave a thin film that makes hair feel limp or coated
- Eye irritation – stinging and watering if the product accidentally drips into the eyes during use
If any of these effects occur discontinue use and consult a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 0 / 5
Polyquaternium-70 is a large, water-soluble polymer that stays on the surface of hair and rinses away easily. Because it does not penetrate pores or mix with skin oils, it has virtually no potential to clog follicles, earning it a solid zero on the comedogenic scale. This makes it suitable for people who are prone to acne or breakouts. As a non-oily conditioning agent it is also unlikely to aggravate conditions like fungal acne. The only exception would be if the finished product contains other pore-clogging ingredients.
Summary
Polyquaternium-70 is a positively charged conditioning polymer that smooths the hair cuticle, cuts static, adds slip and leaves strands looking shinier and softer. It does this by forming an even, lightweight film that binds to damaged negatively charged spots on the hair surface, improving manageability without a heavy feel.
While effective, the ingredient is still a niche choice compared with well-known quats like Polyquaternium-10 or cationic guar, so you will find it in fewer products on the market. Brands that do use it often highlight its light feel and good detangling power.
Current safety data show a very low risk of irritation, no sensitization issues and no links to long-term health concerns, so it is considered safe for regular cosmetic use. As with any new hair care product it is wise to perform a quick patch test before full use, especially for those with sensitive skin or a history of allergies.