C12-15 Alketh-2: 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 C12-15 Alketh-2?

C12-15 Alketh-2 is a man-made ingredient created by reacting a blend of medium-chain fatty alcohols (those with 12 to 15 carbon atoms) with about two units of ethylene oxide. The result is a mild, water-loving substance that belongs to the large family of polyethylene glycol ethers. Chemists first explored this type of material in the mid-20th century while looking for safer and more stable alternatives to soap in liquid cleansers. Over time it proved useful in many personal care formulas because it can mix oil and water without causing skin irritation.

Production starts with plant-derived or petroleum-based fatty alcohols that are purified, then combined with ethylene oxide in a controlled setting. The process links the molecules together, forming a clear or slightly cloudy liquid that dissolves easily in both water and oil. Thanks to this dual nature, C12-15 Alketh-2 soon found its way into everyday products like facial cleansers, body washes, moisturizers, sunscreens, hair conditioners and makeup removers. It is especially valued in lotions and serums where a smooth, non-greasy feel is important.

C12-15 Alketh-2’s Cosmetic Benefits/Uses

Formulators prize C12-15 Alketh-2 for its single but essential role in keeping products stable and pleasant to use.

As an emulsifying agent it binds oil and water into a uniform mixture so creams do not separate on the shelf or leave oily streaks on the skin. This stability allows brands to load formulas with skin-loving oils while still delivering a light texture that rinses clean and absorbs quickly.

Who Can Use C12-15 Alketh-2

C12-15 Alketh-2 is considered gentle enough for most skin types including normal, dry, oily and combination. Because it has a low irritation profile and a lightweight feel, even sensitive skin usually tolerates it, though people with a known allergy to polyethylene glycol derivatives should approach with caution.

The fatty alcohols used to make C12-15 Alketh-2 are typically sourced from plants or petroleum, not animals, so the ingredient is generally suitable for vegans and vegetarians. Those who follow a strict cruelty-free lifestyle may still want to confirm that the finished product or brand aligns with their ethical standards.

No specific safety flags have been raised for pregnant or breastfeeding women when this ingredient is used in rinse-off or leave-on cosmetics. That said this is not medical advice and anyone who is expecting or nursing should show the full ingredient list of any skincare product to a qualified healthcare provider before use.

C12-15 Alketh-2 does not make skin more sensitive to sunlight and it has no known interactions with common active ingredients like retinoids, vitamin C or alpha hydroxy acids. It is also fragrance-free and non-volatile so it will not contribute to scent or evaporation issues in formulas.

Potential Side Effects/Adverse Reactions

Responses to topical ingredients vary from person to person. The effects listed below are possible yet uncommon for C12-15 Alketh-2 when formulated correctly in cosmetic products.

  • Mild skin irritation
  • Temporary redness or stinging on very sensitive skin
  • Allergic contact dermatitis in individuals already sensitized to polyethylene glycol compounds
  • Eye irritation if a product accidentally gets into the eyes

If you notice any of these reactions stop using the product and consult a healthcare professional if symptoms persist.

Comedogenic Rating

Rating: 1 / 5

C12-15 Alketh-2 carries a very low risk of clogging pores because its PEG portion makes the molecule water soluble and easily rinsed away. While the starting fatty alcohols can be pore clogging on their own, attaching just two ethylene oxide units greatly reduces their tendency to linger on skin or form heavy films.

Suitable for acne-prone and breakout-prone skin

Because the ingredient is almost always used at modest levels and typically appears in light lotions or cleansers, it rarely builds up on the skin. Products that combine it with heavier oils could still pose a clogging risk, but the emulsifier itself is not the culprit.

Summary

C12-15 Alketh-2 is an emulsifier that helps oil and water stay perfectly blended, giving creams, lotions and cleansers a smooth uniform texture. It works by surrounding tiny oil droplets with a water-friendly shell so they stay suspended instead of separating.

The ingredient is moderately popular: you will see it in many mainstream formulas but it is not as ubiquitous as some longer chain PEG emulsifiers because newer multifunctional agents sometimes take its place.

Safety profiles from cosmetic regulators and industry testing show it to be low risk for irritation or sensitization when used at the levels found in personal care products. As with any new skincare item it is smart to patch test first to make sure your individual skin tolerates the full formula.

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