What Is C9-11 Pareth-6?
C9-11 Pareth-6 is a non ionic surfactant made by attaching an average of six units of ethylene oxide to fatty alcohols that contain nine to eleven carbon atoms. These fatty alcohols can come from natural oils such as coconut or palm or they can be produced synthetically. The result is a clear to pale liquid that mixes well with both water and oil, a trait that makes it valuable in many personal care formulas.
The cosmetic industry began using ethoxylated fatty alcohols in the 1950s when formulators looked for milder alternatives to soap based cleansers. Over time C9-11 Pareth-6 found a place in modern products because it is gentle, versatile and easy to blend with other ingredients.
Manufacturing starts with the fatty alcohol feedstock. Under controlled heat and pressure ethylene oxide gas is introduced, binding to the alcohol and forming repeating “EO” units. When the average reaches six the reaction is stopped, the mixture is purified and the surfactant is ready for use.
You will most often see C9-11 Pareth-6 in foaming facial cleansers, body washes, shampoos, micellar waters, makeup removers, lotions and lightweight serums that need a bit of emulsifying power without a heavy feel.
C9-11 Pareth-6’s Cosmetic Benefits/Uses
This ingredient offers two main functions that improve both the performance and feel of a product
- Cleansing C9-11 Pareth-6 lowers the surface tension of water so it can surround oil, dirt and makeup, lifting them away from skin or hair. Because it is non ionic it is generally less irritating than many traditional detergents, making formulas feel mild while still producing a satisfying lather.
- Emulsifying Acting as a bridge between oil and water, it keeps creams, lotions and serums from separating. This stable emulsion spreads evenly and feels smooth, enhancing texture and shelf life without the need for heavy waxes.
Who Can Use C9-11 Pareth-6
C9-11 Pareth-6 is generally considered suitable for all skin types including oily, combination, normal and even sensitive skin because its non ionic nature tends to be milder than many other surfactants. People with very dry or compromised skin may want to monitor how their skin feels after use since any surfactant can lead to extra dryness if overused.
The ingredient itself is synthetic and can be sourced from plant derived fatty alcohols, so products that use plant based feedstocks are usually acceptable for vegans and vegetarians. If the label states the fatty alcohols come from coconut or palm rather than animal fat the formula should align with vegan preferences.
Most regulatory bodies rate C9-11 Pareth-6 as safe for use during pregnancy and breastfeeding at the low percentages found in cosmetics. Still, this is not medical advice and anyone who is pregnant or nursing should discuss any skincare products with a healthcare professional to be extra sure.
C9-11 Pareth-6 does not cause photosensitivity so it will not make skin more prone to sunburn. It also has no known impact on hair color longevity or styling treatments when used in shampoos or cleansers.
Potential Side Effects/Adverse Reactions
Reactions to C9-11 Pareth-6 can vary from person to person. The points below outline potential side effects but these are uncommon when the ingredient is used at the levels typically found in cosmetics.
- Mild skin irritation, stinging or redness
- Temporary dryness or tightness of the skin
- Eye irritation if the product accidentally gets into the eyes
- Allergic contact dermatitis in individuals sensitive to ethoxylated compounds
If any irritation or discomfort develops stop using the product and consult a dermatologist or healthcare professional for guidance.
Comedogenic Rating
Rating: 0–1. C9-11 Pareth-6 is a lightweight water-soluble surfactant that rinses away easily and does not leave an oily or occlusive film on the skin, which means it is very unlikely to clog pores. Because of this low residue profile most formulators consider it non-comedogenic.
Given its minimal pore-clogging risk, the ingredient is generally suitable for people prone to acne or breakouts.
While irritation is possible at high concentrations, irritation alone does not equal comedogenicity, so the low rating remains valid.
Summary
C9-11 Pareth-6 is valued for two core jobs: it cleanses by lowering water’s surface tension so grime can be lifted away, and it emulsifies by keeping oil and water blended for smooth stable textures. Its balanced structure—fatty alcohol base plus an average of six ethylene oxide units—lets it perform these roles without feeling heavy.
The ingredient is fairly common in modern cleansers, micellar waters and lightweight lotions though it is not as famous as powerhouse surfactants like SLS or polysorbates. Formulators keep choosing it because it offers mildness, good foam and easy compatibility with other ingredients.
Safety reviews show low toxicity and low irritation potential at the small percentages used in cosmetics. Still, skin is personal so it is wise to patch test any new product that contains C9-11 Pareth-6.