C12-15 Pareth-12 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 The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is C12-15 Pareth-12 Carboxylic Acid?

C12-15 Pareth-12 Carboxylic Acid is a synthetic ingredient created by linking natural-origin fatty alcohols that contain 12 to 15 carbon atoms with an average of 12 units of ethylene oxide, then converting one end of the chain into a carboxylic acid group. The resulting molecule is part oil loving, part water loving, so it easily mixes the two phases together.

Surfactants built on this fatty-alcohol-plus-polyethylene-glycol structure began appearing in personal care during the late twentieth century when formulators were looking for milder alternatives to traditional soaps and sulfates. The carboxylic acid variation offered extra flexibility because it could perform well over a broad pH range and pair with other cleansing agents for balanced formulas.

Manufacturing starts with plant-derived or petroleum-based C12-C15 fatty alcohols. These alcohols are reacted with ethylene oxide to attach the polyethylene glycol section. A controlled oxidation step then adds the carboxylic acid group, followed by purification to remove residual reactants.

You will most often find C12-15 Pareth-12 Carboxylic Acid in face cleansers, body washes, micellar waters, foaming masks, shampoo bases, makeup-removing wipes and gentle exfoliating scrubs. Its ability to cleanse without stripping makes it popular in products aimed at sensitive or dryness-prone skin.

C12-15 Pareth-12 Carboxylic Acid’s Cosmetic Benefits/Uses

This ingredient serves a single but important purpose in cosmetic formulas.

As a cleansing agent it lowers surface tension so water can spread across the skin or hair, loosens dirt, oil and product buildup, then helps rinse them away. Because the molecule is only moderately foaming it produces a soft creamy lather that feels mild yet still leaves skin fresh and comfortable.

Who Can Use C12-15 Pareth-12 Carboxylic Acid

Because it cleanses gently while keeping the skin’s natural moisture barrier intact, C12-15 Pareth-12 Carboxylic Acid works for nearly every skin type: normal, dry, oily, combination and even sensitive or redness-prone complexions. It is unlikely to clog pores so acne-prone users can generally tolerate it as well. There are no specific skin types that need to avoid the ingredient unless they have a known sensitivity to polyethylene glycol-based surfactants.

The material is produced from plant-derived or petroleum-derived fatty alcohols and manufactured without animal by-products, making it suitable for both vegans and vegetarians.

Current safety assessments show no reproductive or developmental risks at the trace levels left on skin after rinsing, so products containing this surfactant are considered acceptable for pregnant or breastfeeding consumers. This is not medical advice; anyone who is pregnant or nursing should review their personal care routine with a qualified healthcare provider.

The ingredient does not absorb UV light and is not known to cause photosensitivity, so it will not make skin more prone to sunburn. It is also fragrance-free and dye-free in its raw form which can be helpful for users trying to avoid common irritants.

Potential Side Effects/Adverse Reactions

Individual responses to topical C12-15 Pareth-12 Carboxylic Acid can vary. The points below describe potential reactions only; when used at the concentrations typically found in finished products most people will not experience any issues.

  • Mild skin irritation such as temporary redness or stinging, more likely in very sensitive skin
  • Dryness or tightness if used in a formula that is left on the skin too long or if the overall routine is overly stripping
  • Eye irritation if the product is accidentally rubbed into the eyes before rinsing
  • Allergic contact dermatitis in individuals already sensitized to polyethylene glycol derivatives, though this is uncommon

If any discomfort, rash or unexpected reaction occurs stop using the product and consult a healthcare professional.

Comedogenic Rating

Rating: 0 – C12-15 Pareth-12 Carboxylic Acid is a water soluble surfactant that does not leave an oily or waxy film on skin, so it has virtually no pore-clogging potential. Its molecules are rinsed off easily and are too large and polar to lodge inside follicles.

Suitable for acne-prone and breakout-prone skin.

Because it is usually found in wash-off products the contact time is short, further lowering any risk of buildup that could contribute to congestion.

Summary

C12-15 Pareth-12 Carboxylic Acid is a mild cleansing agent that loosens dirt and oil then helps water whisk them away without stripping the skin barrier. Its balanced oil-loving and water-loving structure lets it create a creamy low-foam lather that feels gentle yet effective.

While not as famous as sulfates or trendy plant surfactants it shows up quietly in many facial cleansers body washes and micellar formulas aimed at sensitive or dry skin because formulators value its flexibility across pH ranges and its mildness.

Safety reviews and decades of use show a low risk of irritation or systemic harm when the ingredient is used as directed in rinse-off products. Still it is smart to patch test any new product just to be sure it agrees with your individual skin.

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