C12-15 Alketh-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 Alketh-12 Carboxylic Acid?

C12-15 Alketh-12 Carboxylic Acid is a man-made ingredient created from a blend of medium-chain fatty alcohols that come from natural sources such as coconut or palm oil. Chemists attach about 12 units of ethylene oxide to these alcohols, then convert one end of the molecule into a gentle acid group. The result is a mild surfactant that loves both oil and water, which makes it ideal for lifting grime from the skin and letting it rinse away easily.

Surfactants based on fatty alcohols first appeared in personal care lines in the 1960s as a softer option than traditional soap. Over time formulators fine-tuned them for better foam, less irritation and easier manufacturing. C12-15 Alketh-12 Carboxylic Acid is one of those later improvements, offering a good balance of cleaning power and skin friendliness.

The ingredient is produced in large reactors where the fatty alcohol blend is ethoxylated, then carefully oxidized. Quality checks make sure the average of 12 ethoxy units is on target because that number controls how well the molecule performs in water.

You will most often spot this acid in facial cleansers, body washes, shampoos, micellar waters, makeup removers, exfoliating masks and cleansing wipes. A small amount may also appear in rinse-off lotions or lightweight serums to help them wash away without leaving a film.

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

This ingredient is prized for one key job in skin and hair care formulas

Cleansing: As a surfactant it loosens dirt, excess oil, sunscreen and makeup then suspends them in water so they rinse off cleanly. It creates a soft, low-irritation lather, helps products spread evenly and leaves skin feeling fresh rather than tight or squeaky.

Who Can Use C12-15 Alketh-12 Carboxylic Acid

This gentle surfactant is generally suitable for all skin types including oily, combination, normal and dry. Sensitive skin usually tolerates it well thanks to its mild nature though people with very reactive skin should still keep an eye on how their skin feels after use. There are no known issues for darker skin tones or acne-prone skin

C12-15 Alketh-12 Carboxylic Acid is synthesized from plant-derived fatty alcohols and contains no animal-sourced material so it aligns with vegan and vegetarian preferences

No data suggest that topical use poses specific risks for pregnant or breastfeeding women. Still this is not medical advice and anyone who is expecting or nursing should confirm product choices with a healthcare professional to be safe

The ingredient does not make skin more sensitive to sunlight so it is not considered photosensitizing. It also plays well with common actives like retinoids, vitamin C and exfoliating acids because it rinses off rather than lingers on the skin

Potential Side Effects/Adverse Reactions

Responses to C12-15 Alketh-12 Carboxylic Acid differ from person to person. The points below outline potential side effects that could occur even though most users will not notice any problems when the ingredient is properly formulated and used as directed

  • Mild temporary dryness very rare but can happen if the cleanser is left on the skin for an extended time or used too frequently
  • Light irritation or stinging usually linked to over-cleansing or pre-existing skin barrier damage
  • Eye discomfort if the product accidentally gets into the eyes while washing
  • Allergic contact dermatitis an uncommon immune response leading to redness itching or small bumps

If any of these issues occur stop using the product and consult a healthcare provider if symptoms persist or worsen

Comedogenic Rating

Rating: 1 / 5

C12-15 Alketh-12 Carboxylic Acid is highly water soluble and designed to rinse off cleanly so it does not linger on the skin or mix with sebum in a way that could block pores. Its large hydrophilic portion keeps it moving with water rather than settling into follicle openings which is why formulators consider it very low on the clogging scale.

Because of this low rating most people who are prone to acne or breakouts should find it suitable in rinse-off products.

The only situation where residue might build up is if a formula contains heavy oils or waxes alongside this surfactant and is not rinsed thoroughly though that scenario is more about the rest of the formula than the ingredient itself.

Summary

C12-15 Alketh-12 Carboxylic Acid is a plant-derived surfactant whose main job is cleansing. Its oil-loving tail grabs on to dirt makeup and excess sebum while the water-loving head lets everything wash away, leaving skin or hair fresh and comfortable.

You will not see its name splashed across marketing campaigns but it quietly shows up in a wide range of face washes body cleansers and shampoos because it offers the sweet spot of gentle feel and reliable cleaning power that formulators need.

Current research and decades of use suggest it is safe for all skin types, with only rare reports of irritation or allergy when used as directed. As with any new skincare product a small patch test is a smart step before regular use just to make sure your skin likes what you are giving it.

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