C12-13 Pareth-7 Carboxylic Acid: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 24, 2025
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All information on this page is verified using publicly available nomenclature standards and reference materials from The Personal Care Products Council (PCPC) and the European Commission's CosIng database. Our analyses are based on technical data from these sources to ensure accuracy and reliability.

What Is C12-13 Pareth-7 Carboxylic Acid?

C12-13 Pareth-7 Carboxylic Acid is a synthetic ingredient made by linking fatty alcohols that come from coconut or palm oil (with 12 to 13 carbon atoms) to small units of ethylene oxide, then adding a mild acid group at one end. The result is a clear to slightly hazy liquid that mixes easily with water and oils. Chemists began exploring this type of molecule in the late twentieth century when they were looking for gentler cleansers than traditional soaps. Because the fatty part is plant based and the ethylene oxide part is made in the lab, the ingredient offers a balance of natural sourcing and controlled manufacturing.

Production starts with the fatty alcohols, which are reacted with ethylene oxide in a controlled setting to build an average of seven repeating units. The last step introduces a carboxylic acid group that improves water solubility and mildness. Every batch is filtered and purified to meet cosmetic grade standards.

You will most often see C12-13 Pareth-7 Carboxylic Acid in rinse off products such as shampoos, body washes, facial cleansers and hand soaps. It can also appear in micellar waters, makeup removers and scrub formulas where a gentle yet effective cleanser is needed. Leave on creams rarely use it, but some lightweight lotions include small amounts to help them rinse cleanly if layered or used in the shower.

C12-13 Pareth-7 Carboxylic Acid’s Cosmetic Benefits/Uses

This ingredient is valued for one key role in personal care formulas

Cleansing: C12-13 Pareth-7 Carboxylic Acid lowers the surface tension of water so oils, dirt and leftover makeup can lift away more easily. It creates a soft foam, rinses quickly and leaves little residue, which helps products feel fresh and non stripping on skin and hair.

Who Can Use C12-13 Pareth-7 Carboxylic Acid

C12-13 Pareth-7 Carboxylic Acid is generally well tolerated by most skin types, including normal, oily and combination skin, thanks to its mild cleansing action and quick rinse off. Dry or very sensitive skin can also use it in low to moderate amounts, though highly reactive complexions might prefer formulas that pair it with extra soothing agents because any surfactant has the potential to disturb an already fragile moisture barrier.

The ingredient is plant derived and produced without animal by products, making it suitable for both vegans and vegetarians. The fatty alcohols come from coconut or palm sources and the rest of the molecule is synthesized in a laboratory, so no animal testing is involved at the ingredient level according to standard supplier documentation.

No specific warnings exist for pregnant or breastfeeding women when it is used at the low percentages typical of rinse off or leave on cosmetics. That said, this is not medical advice and anyone who is pregnant or nursing should discuss all skincare choices with a qualified healthcare professional to be safe.

C12-13 Pareth-7 Carboxylic Acid does not make skin more sensitive to the sun and carries no known photosensitivity risk. It is also biodegradable and considered non persistent in the environment, which matters to eco-conscious users.

Potential Side Effects/Adverse Reactions

Responses to topical C12-13 Pareth-7 Carboxylic Acid vary from person to person. The effects listed below are possible but uncommon when the ingredient is used at cosmetic levels in properly formulated products.

  • Temporary dryness or tightness, especially on very dry skin if the formula is not followed by a moisturizer
  • Mild redness or stinging on highly sensitive or compromised skin
  • Eye irritation if the product accidentally gets into the eyes
  • Rare allergic contact dermatitis in individuals already sensitized to similar ethoxylated surfactants

If any irritation, redness or discomfort occurs, discontinue use and seek advice from a medical professional.

Comedogenic Rating

Rating: 1/5. C12-13 Pareth-7 Carboxylic Acid is a water-soluble cleansing agent that rinses off almost completely so it is unlikely to clog pores. Its fatty alcohol backbone is balanced by seven ethylene oxide units and a carboxylic acid head, which keep the molecule dispersed in water rather than depositing on skin. Because it is not oily or film-forming, the chance of it trapping dead cells or sebum inside pores is very low. It earns a 1 instead of 0 only because any ingredient derived from fatty chains can, in theory, leave minimal residue in leave-on formulas.

Suitable for acne-prone and breakout-prone skin in both rinse-off and low-level leave-on products.

As a rinse-off surfactant it may actually help reduce surface oil that could otherwise contribute to congestion, provided the formula is gentle enough not to trigger rebound oiliness.

Summary

C12-13 Pareth-7 Carboxylic Acid is a mild plant-derived surfactant that lowers surface tension so water can remove dirt oil and makeup. Its balanced structure produces light foam, quick rinsing and minimal residue which leaves skin and hair feeling clean but not stripped.

The ingredient sits in the middle lane of popularity: common enough to appear in modern shampoos body washes and micellar waters yet not as ubiquitous as classic sulfates or coco glucosides. Formulators reach for it when they want gentle cleansing without heavy cost or complex handling.

Overall safety is high with a low irritation profile, biodegradability and a very low comedogenic score. While adverse reactions are rare every skin type is unique so it is wise to perform a small patch test when trying any new product that contains C12-13 Pareth-7 Carboxylic Acid just to be sure.

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