What Is C11-15 Alketh-12 Stearate?
C11-15 Alketh-12 Stearate is an ester created by reacting C11-15 Alketh-12, a synthetic blend of fatty alcohols that have been ethoxylated, with stearic acid, a long-chain fatty acid commonly sourced from plant oils such as coconut or palm. The result is a creamy, wax-like material that is oil-loving yet dispersible in water-based formulas, making it valuable in modern skin care and hair care.
The ingredient first appeared in cosmetic labs in the late 1980s when formulators were searching for gentle alternatives to mineral oil and lanolin derivatives. By combining the cushioning feel of stearic acid with the light texture of mid-length alcohols, chemists achieved a softer, more spreadable emollient that suited a wide range of skin types.
Manufacturing involves two steps. First, C11-15 fatty alcohols are reacted with ethylene oxide to attach roughly 12 oxyethylene units, creating C11-15 Alketh-12. Second, this intermediate is esterified with stearic acid under controlled heat and vacuum. The process yields a stable ingredient with a consistent melting point, ensuring batch-to-batch uniformity for cosmetic use.
Thanks to its silky glide and non-greasy finish, C11-15 Alketh-12 Stearate shows up in moisturizers, face masks, body lotions, sunscreens, anti-aging serums and conditioning hair masks. It often partners with other emollients and emulsifiers to build a pleasant skin feel and reinforce the moisture barrier.
C11-15 Alketh-12 Stearate’s Cosmetic Benefits/Uses
Formulators reach for C11-15 Alketh-12 Stearate when they want to improve texture and boost skin comfort.
As an emollient it fills the tiny gaps between skin cells to smooth rough patches, soften the surface and reduce moisture loss. Its balanced molecular weight lets it spread easily without feeling heavy so products glide on effortlessly and leave a velvety after-feel that many users describe as “silky but breathable.”
Who Can Use C11-15 Alketh-12 Stearate
This silky emollient is generally well tolerated by all skin types. Dry, normal and combination skin tend to appreciate its cushioning feel while oily and acne-prone skin usually find it light enough not to cause greasiness. Extremely reactive or highly acne-prone users should still pay attention to the overall formula since heaviness often comes from companion ingredients rather than C11-15 Alketh-12 Stearate itself.
The ingredient can be suitable for vegans and vegetarians when the stearic acid portion is sourced from plants like coconut or palm. Some manufacturers may still use animal-derived stearic acid so label readers who avoid animal by-products should look for brands that specify “vegetable derived” or confirm sourcing with customer service.
No data suggest it poses problems for pregnant or breastfeeding women when used topically in cosmetics. That said this is not medical advice and expectant or nursing mothers should run any skincare product past a qualified healthcare provider to be on the safe side.
C11-15 Alketh-12 Stearate does not make skin more sensitive to sunlight and has no known interaction with UV exposure. It also plays nicely with most other common skincare ingredients making it versatile for layered routines.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient can vary from person to person. The following list covers potential side effects but these outcomes are uncommon when the finished product is formulated and used as directed.
- Mild skin irritation such as transient redness or itching on very sensitive skin
- Allergic contact dermatitis in individuals who develop a rare sensitivity to fatty alcohol derivatives
- Clogged pores on skin that is extremely prone to comedones especially if layered with other heavy oils or waxes
- Eye irritation if the ingredient contacts the eyes in high concentrations before being rinsed away
If you notice any persistent discomfort or reaction stop using the product and consult a healthcare professional
Comedogenic Rating
Rating: 1 / 5
C11-15 Alketh-12 Stearate sits low on the scale because its molecular structure is larger and more water-dispersible than heavier butters and waxes, so it does not lodge easily inside pores. Most lab and consumer reports show minimal pore clogging even at higher use levels in lotions and creams.
Suitable for acne-prone skin in the majority of formulas, though the overall product’s oil load and the presence of other rich emollients matter more than this single ingredient.
Like many fatty alcohol esters it may feel richer in high-oil balms or sunscreens, so very oily complexions might still prefer lighter textures.
Summary
C11-15 Alketh-12 Stearate is a mid-weight emollient that smooths rough skin, fills micro-gaps in the surface and leaves a soft breathable finish. It achieves this by combining a water-friendly ethoxylated backbone with the cushiony slip of stearic acid, giving formulas an elegant glide without greasy residue.
While not as famous as shea butter or squalane it shows up quietly in many moisturizers, masks, sunscreens and hair treatments because it delivers reliable texture improvement at an affordable cost.
Current safety data rate it as low risk for irritation or toxicity when used as directed. Still, everyone’s skin is unique so it is smart to patch test any new product that lists C11-15 Alketh-12 Stearate to ensure personal compatibility.