Ingredient review
C12-13 Pareth-5 Carboxylic Acid
INCI: C12-13 PARETH-5 CARBOXYLIC ACID
A gentle, non-stripping surfactant that effectively cleanses while being kind to sensitive skin.
In plain English
This ingredient is a mild soap-like molecule that helps water mix with oil and dirt so they can be rinsed away. It's made from natural fatty alcohols (from coconut or palm oil) and modified to be less harsh than traditional soaps. Because it's a carboxylic acid form, it works well at a skin-friendly pH and leaves the skin feeling clean but not tight or dry.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- semi synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
C12-13 Pareth-5 Carboxylic Acid is generally a lower-concern ingredient when the full formula suits your skin.
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 C12-13 Pareth-5 Carboxylic Acid.
- 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
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
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
C12-13 Pareth-5 Carboxylic Acid is a semi-synthetic surfactant created by reacting a fatty alcohol (C12-13, derived from plant oils) with ethylene oxide and then converting it to a carboxylic acid. This structure gives it both water-loving and oil-loving properties, making it an effective cleanser and emulsifier.
How it works
In a product, this molecule surrounds oil and dirt particles, breaking them into tiny droplets that can be rinsed away with water. Its mildness comes from its large, gentle head group that doesn't disrupt the skin's natural barrier as much as stronger surfactants like sodium lauryl sulfate.
Pros
Mild on skin
Its large molecular structure makes it less likely to irritate or strip the skin, ideal for daily use on sensitive or dry skin.
pH-friendly
Works effectively at a slightly acidic pH (around 5.5–6.5), which matches the skin's natural pH and helps maintain a healthy barrier.
Cons and cautions
Limited foaming
Produces a lower, creamier lather compared to traditional sulfates, which some users may perceive as less effective.
Processing concerns
Made via ethoxylation, a chemical process that can create trace impurities (1,4-dioxane) if not properly purified, though reputable manufacturers control this.
Best for
- People with dry or sensitive skin looking for a gentle cleanser
- Anyone wanting to avoid harsh sulfates in their skincare routine
Use caution if
- Those seeking a very deep cleanse for heavy oil or waterproof makeup (may need a double-cleanse step)
Usage tips
Safety summary
Considered safe for cosmetic use at typical concentrations. The main concern is potential trace contamination from the manufacturing process, which is tightly regulated. For most users, it is a very low-irritation option.
Research notes
Studies on similar alkyl ether carboxylic acids show they are significantly milder than traditional anionic surfactants like SLS, with less protein denaturation and skin barrier disruption. Human patch tests confirm low irritation potential.
Common label clues
- Typical concentration
- 1–10% in rinse-off products; lower in leave-on formulas
- Regulatory status
- Approved for use in cosmetics in the EU, US, and other major markets. The Cosmetic Ingredient Review (CIR) panel has evaluated similar ethoxylated surfactants and found them safe when formulated within concentration limits.
- Common uses
- Cleansers, Facial washes, Body washes, Shampoos, Makeup removers
- Environmental note
- Derived from plant-based fatty alcohols (often coconut or palm oil), but the ethoxylation process is energy-intensive. Biodegradability is generally good, but sourcing of palm oil should be certified sustainable.
Good to know
- Often listed in 'sulfate-free' formulas as a primary surfactant.
- The 'C12-13' refers to the carbon chain length of the fatty alcohol source, which influences its mildness and cleansing power.
Common questions
What is C12-13 Pareth-5 Carboxylic Acid in beauty products?
This ingredient is a mild soap-like molecule that helps water mix with oil and dirt so they can be rinsed away. It's made from natural fatty alcohols (from coconut or palm oil) and modified to be less harsh than traditional soaps. Because it's a carboxylic acid form, it works well at a skin-friendly pH and leaves the skin feeling clean but not tight or dry.
What does C12-13 Pareth-5 Carboxylic Acid do in a beauty product?
In a product, this molecule surrounds oil and dirt particles, breaking them into tiny droplets that can be rinsed away with water. Its mildness comes from its large, gentle head group that doesn't disrupt the skin's natural barrier as much as stronger surfactants like sodium lauryl sulfate.
Is C12-13 Pareth-5 Carboxylic Acid safe for most people?
Considered safe for cosmetic use at typical concentrations. The main concern is potential trace contamination from the manufacturing process, which is tightly regulated. For most users, it is a very low-irritation option.
Who should be careful with C12-13 Pareth-5 Carboxylic Acid?
Those seeking a very deep cleanse for heavy oil or waterproof makeup (may need a double-cleanse step)
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.