What Is C40-60 Alkyl Stearate?
C40-60 Alkyl Stearate, also written as C40-60-alkyl octadecanoate, is an ester made by combining long chain fatty alcohols that have 40 to 60 carbon atoms with stearic acid, a fatty acid found in plants and animals. Chemists began using fatty acid esters in personal care products in the 1960s when they were looking for plant based alternatives to mineral oils. Today most suppliers create C40-60 Alkyl Stearate through esterification, a process that joins the fatty alcohols and stearic acid under heat with a small amount of catalyst, then purifies the mix until it meets cosmetic grade standards.
The ingredient has a wax like feel and a high melting point, which makes it useful as a thickening and skin softening agent. You will usually spot it in moisturizers, sunscreens, lip balms, foundations, solid cleansers, and anti aging creams where it helps improve texture and glide.
C40-60 Alkyl Stearate’s Cosmetic Benefits/Uses
C40-60 Alkyl Stearate is valued mainly for one key job in skin care products.
As a skin conditioning agent it forms a light, breathable layer on the surface that reduces moisture loss and leaves skin feeling smooth and supple. Its waxy nature also adds body to creams and sticks, giving formulas a rich yet non greasy finish and helping pigments or UV filters spread evenly.
Who Can Use C40-60 Alkyl Stearate
Most skin types tolerate C40-60 Alkyl Stearate well. Dry and mature skin often benefit the most from its moisture sealing film while normal and combination skin usually find it comfortable in the low to moderate amounts found in lotions and makeup. Those with very oily or acne prone skin might find heavy formulas containing high levels of this waxy ester a bit too rich, which could leave the surface feeling greasy.
The ingredient itself can be made from either plant or animal sources. Many cosmetic suppliers rely on coconut or palm derived fatty alcohols and plant based stearic acid so vegetarian and vegan users can often find clearly labeled products that meet their needs. Anyone following a strict plant only routine should still double check the brand’s sourcing statement to be sure.
C40-60 Alkyl Stearate is not known to enter the bloodstream in meaningful amounts when applied to intact skin so it is generally considered safe for use during pregnancy and breastfeeding. This information is not medical advice and pregnant or nursing individuals should show any skincare product to their doctor just to be on the safe side.
The ester does not make skin more sensitive to sunlight and it plays well with common active ingredients like retinol, vitamin C and sunscreens.
Potential Side Effects/Adverse Reactions
Reactions to topical C40-60 Alkyl Stearate differ from person to person. The points below outline potential side effects, but most users will not experience them when the ingredient is used correctly in a well formulated product.
- Mild skin irritation – a small number of people may notice redness, stinging or itching
- Contact allergy – very rare cases of allergic dermatitis can occur in individuals sensitive to fatty alcohols or stearic acid derivatives
- Clogged pores – heavy or occlusive formulas containing large amounts of the ester could contribute to breakouts in highly acne prone skin
- Greasy feel or shine – some users with oily skin may dislike the richer texture it adds
If you experience any negative reaction stop using the product and consult a healthcare professional or dermatologist for guidance.
Comedogenic Rating
Rating: 2 out of 5
C40-60 Alkyl Stearate is a large waxy ester that mostly stays on the surface of the skin. Its size makes it less likely to slip into pores compared with smaller oils, but the occlusive film it forms can still trap debris if used in high amounts or in very heavy formulas. Because of this balanced profile it earns a 2, meaning it is low to moderate on the pore-clogging scale.
Most people, including those with the occasional breakout, tolerate it fine in well-balanced products. Very acne-prone users should keep an eye on how their skin reacts, especially with rich balms or solid makeup sticks that list the ester near the top of the ingredient list.
Comedogenicity also depends on the full recipe of the product. When paired with light emollients or used at low levels the risk of clogged pores drops even further.
Summary
C40-60 Alkyl Stearate is mainly a skin-conditioning and thickening agent. It creates a soft, breathable film that locks in moisture, smooths texture and gives creams, sticks and balms a richer feel without leaving a heavy oily residue.
The ester sits in the middle ground of popularity. It is not a headline ingredient like hyaluronic acid yet formulators reach for it often when they need a plant-based wax to add body and glide, so it quietly appears in many moisturizers, sunscreens and makeup products.
Safety data show it is well tolerated by most skin types, including during pregnancy and breastfeeding, with only rare reports of irritation or allergy. As with any new product it is wise to patch test first to make sure your skin gets along with the full formula.