Ingredient review
C11-13 Pareth-9
INCI: C11-13 Pareth-9
A gentle synthetic cleanser that helps remove dirt and oil without stripping the skin, but may cause mild irritation for very sensitive types.
In plain English
C11-13 Pareth-9 is a man-made ingredient that helps cleansers foam and lift dirt and oil from your skin so they can be rinsed away. It belongs to a family of ingredients called ethoxylated alcohols, which are made by reacting fatty alcohols with ethylene oxide. In skincare, it acts as a gentle surfactant—think of it as a mild soap that doesn't dry out your skin as much as traditional soaps. It also helps blend water and oil in creams and lotions, keeping them smooth and stable.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
C11-13 Pareth-9 can be useful, but watch for some irritation potential.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging C11-13 Pareth-9.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic surfactant derived from a blend of C11-13 fatty alcohols (from coconut or palm oil) that have been reacted with an average of 9 units of ethylene oxide. This process creates a water-loving molecule that can trap oil and dirt.
How it works
Its molecule has one end that attracts water and another that attracts oil. When you wash your face, the oil-loving end grabs onto sebum, makeup, and impurities, while the water-loving end lets everything rinse away with water. This dual action makes it effective at cleansing without needing harsh scrubbing.
Pros
Gentle cleansing
Removes dirt and oil effectively without stripping the skin's natural moisture barrier, making it suitable for daily use.
Good foam quality
Produces a rich, creamy lather that feels pleasant on the skin and helps spread the product evenly.
Cons and cautions
Potential irritation
Can cause mild stinging or redness in people with very sensitive or damaged skin, especially in leave-on products.
Processing concerns
As an ethoxylated ingredient, it may contain trace levels of 1,4-dioxane if not rigorously purified, though reputable brands ensure low levels.
Best for
- People with normal to oily skin looking for a gentle daily cleanser
- Those who prefer synthetic cleansers over soap-based ones
Use caution if
- Individuals with severely compromised skin barriers or active eczema should patch-test first
Usage tips
Safety summary
C11-13 Pareth-9 is considered safe for use in cosmetics at typical concentrations. The main safety concern is the potential presence of 1,4-dioxane, a byproduct of ethoxylation, but reputable manufacturers purify to very low levels. It is generally well-tolerated but may cause mild irritation in sensitive individuals.
Research notes
Studies on ethoxylated alcohols indicate they are effective surfactants with low acute toxicity. The Cosmetic Ingredient Review (CIR) panel has reviewed similar ethoxylated alcohols and found them safe for use in rinse-off products. Research on 1,4-dioxane contamination has led to strict purification standards in the industry.
Common label clues
- Typical concentration
- 0.5% to 5% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the EU, US, and many other regions. The EU restricts 1,4-dioxane levels to 10 ppm in finished products.
- Common uses
- Cleansers, Shampoos, Body washes, Emulsions
- Environmental note
- Derived from plant-based fatty alcohols (coconut or palm oil), but the ethoxylation process is energy-intensive. Biodegradability is moderate; check for eco-certifications.
Good to know
- This ingredient is often used in 'sulfate-free' cleansers as a milder alternative to sodium lauryl sulfate.
- The number '9' refers to the average number of ethylene oxide units, which influences its water solubility and mildness.
Common questions
What is C11-13 Pareth-9 in beauty products?
C11-13 Pareth-9 is a man-made ingredient that helps cleansers foam and lift dirt and oil from your skin so they can be rinsed away. It belongs to a family of ingredients called ethoxylated alcohols, which are made by reacting fatty alcohols with ethylene oxide. In skincare, it acts as a gentle surfactant—think of it as a mild soap that doesn't dry out your skin as much as traditional soaps. It also helps blend water and oil in creams and lotions, keeping them smooth and stable.
What does C11-13 Pareth-9 do in a beauty product?
Its molecule has one end that attracts water and another that attracts oil. When you wash your face, the oil-loving end grabs onto sebum, makeup, and impurities, while the water-loving end lets everything rinse away with water. This dual action makes it effective at cleansing without needing harsh scrubbing.
Is C11-13 Pareth-9 safe for most people?
C11-13 Pareth-9 is considered safe for use in cosmetics at typical concentrations. The main safety concern is the potential presence of 1,4-dioxane, a byproduct of ethoxylation, but reputable manufacturers purify to very low levels. It is generally well-tolerated but may cause mild irritation in sensitive individuals.
Who should be careful with C11-13 Pareth-9?
Individuals with severely compromised skin barriers or active eczema should patch-test first
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.