What Is C11-15 Pareth-7?
C11-15 Pareth-7 is a group of fatty alcohols that have been reacted with about seven units of ethylene oxide. The alcohol part comes from medium-length carbon chains that sit between C11 and C15, which can be sourced from plant oils or petroleum. The ethoxylation step turns these otherwise oily alcohols into water-friendly molecules, giving them the useful qualities of a non-ionic surfactant.
The idea of blending fatty alcohols with ethylene oxide has been around since the mid-20th century when chemists looked for gentle alternatives to the harsh soaps used at the time. Over the years C11-15 Pareth-7 proved reliable, cost-effective and mild, so it found a home in mainstream beauty formulas.
Making the ingredient is straightforward on an industrial scale. First, the chosen C11-15 alcohols are purified. Next, under controlled heat, pressure and in the presence of a catalyst, ethylene oxide gas is added. The reaction stops once the average of seven ethylene oxide units per alcohol molecule is reached. The final liquid is then filtered and quality-checked before shipping to cosmetic manufacturers.
You will spot C11-15 Pareth-7 in a wide range of products such as facial cleansers, micellar waters, body washes, shampoos, makeup removers, light lotions, serums and sheet mask essences. Brands value it for its mildness and its ability to blend oil and water into smooth, stable emulsions.
C11-15 Pareth-7’s Cosmetic Benefits/Uses
This multitasking ingredient pulls its weight in formulas through two main roles
- Cleansing: As a non-ionic surfactant it loosens and lifts away dirt, excess oil and makeup without stripping the skin or hair. This makes washes and shampoos feel gentle yet effective
- Emulsifying: It helps oil and water stay mixed, giving creams, lotions and serums a uniform texture that feels light and absorbs evenly
Who Can Use C11-15 Pareth-7
Thanks to its gentle, non ionic nature C11-15 Pareth-7 suits most skin types, including dry, oily, combination and acne prone. Its mildness also makes it a good match for sensitive skin though anyone with an already damaged or highly reactive barrier should still approach any new formula carefully.
The fatty alcohol portion can be sourced from plants or petroleum, not animals, so the ingredient itself is typically considered vegan and vegetarian friendly. Those who follow a strict lifestyle may want to confirm that the finished product is certified cruelty free and that plant derived feedstocks were used.
No published data links topical use of C11-15 Pareth-7 to problems during pregnancy or while breastfeeding. Absorption through intact skin is minimal, yet this is not medical advice and anyone who is pregnant or nursing should run their skincare choices past a qualified doctor to be safe.
The ingredient does not make skin more sensitive to sunlight and there are no known issues regarding interaction with UV exposure.
Potential Side Effects/Adverse Reactions
Reactions to C11-15 Pareth-7 vary between individuals. The points below show what could happen although most people will not notice any problems when the ingredient is used at the levels found in finished cosmetics.
- Mild skin irritation
- Redness or stinging on very compromised skin
- Rare allergic contact dermatitis
- Eye irritation if the product accidentally gets into the eyes
- Dry or tight feeling when used in overly high concentrations
If you experience discomfort or any of the listed effects stop using the product and seek advice from a healthcare professional or dermatologist.
Comedogenic Rating
Rating: 1 / 5
C11-15 Pareth-7 is mostly water-soluble thanks to the seven ethylene oxide units attached to each fatty alcohol. This makes the molecule rinse away easily rather than sitting in pores, so its clogging potential is very low. The base alcohol chains are medium length, which on their own could be pore-clogging, but the ethoxylation process greatly reduces that risk.
Because of this low score, products that use C11-15 Pareth-7 are generally fine for acne-prone or breakout-prone skin.
Note that finished formulas may also contain heavier oils or waxes that raise the overall comedogenicity, so always look at the full ingredient list.
Summary
C11-15 Pareth-7 acts as a gentle cleanser and as an emulsifier. The surfactant part grabs oil and grime while its water-loving side lets everything rinse away cleanly. In creams and lotions it positions itself at the boundary of oil and water phases, holding them together so the texture stays smooth and light.
It is a workhorse ingredient found in many everyday cleansers, shampoos and lightweight leave-on products. While not as famous as trendy actives like niacinamide or hyaluronic acid, formulators reach for it often because it does its job quietly, reliably and at a reasonable cost.
Studies and decades of use show C11-15 Pareth-7 to be low in irritation and low in comedogenicity when used at typical cosmetic levels. Still, every skin is unique, so it is wise to patch test a new product that contains this ingredient before applying it more widely.