C18-38 Alkyl C24-54 Acid Ester: 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 C18-38 Alkyl C24-54 Acid Ester?

C18-38 Alkyl C24-54 Acid Ester is a group of long chain fatty alcohols (with 18 to 38 carbon atoms) joined to very long chain fatty acids (with 24 to 54 carbon atoms) to form smooth waxy esters. These building blocks are usually sourced from renewable plant oils such as coconut, rapeseed or sunflower, though they can also be produced synthetically for consistent quality. The ingredient first found its way into cosmetics in the late twentieth century when formulators looked for plant based alternatives that could give creams and lotions a richer feel without using heavy mineral oils.

Making the ester is straightforward: the fatty alcohols and fatty acids are heated together with a food grade catalyst until they bond, then the mixture is purified and cooled. The result is a neutral, odorless material that melts easily on skin yet stays solid at room temperature. Because of these traits it shows up in moisturizers, anti aging creams, balms, masks, stick sunscreens, lipsticks and hair conditioners where a soft velvety texture is desired.

C18-38 Alkyl C24-54 Acid Ester’s Cosmetic Benefits/Uses

In everyday skin and hair products this ingredient serves mainly one job that delivers several practical advantages.

Viscosity controlling: By thickening the oil phase of a formula it helps create stable creams and lotions that do not separate, gives serums a cushy feel, allows balms and sticks to hold their shape and lets light emulsions feel richer without feeling greasy.

Who Can Use C18-38 Alkyl C24-54 Acid Ester

This silky wax suits most skin types including dry, normal and mature because it locks in moisture without feeling heavy. Oily or very acne prone users usually tolerate it too since the ester is lighter than many traditional plant oils though extremely congested skin might prefer to keep usage minimal.

The raw material is typically sourced from plant oils and no animal byproducts are involved so it aligns well with vegetarian and vegan lifestyles. If you follow a strict cruelty free routine just check that the finished brand also avoids animal testing.

Current data shows no hormonal activity so products containing this ester are generally considered safe for pregnant or breastfeeding women. That said this is not medical advice and anyone expecting or nursing should run the full ingredient list of a product past a healthcare professional to be sure it fits their personal situation.

The molecule does not absorb UV light and is not known to cause photosensitivity so it will not make skin more prone to sunburn.

Potential Side Effects/Adverse Reactions

Reactions to topical C18-38 Alkyl C24-54 Acid Ester vary from person to person. The points below cover potential side effects yet most users will never encounter them when the ingredient is used correctly in a finished cosmetic.

  • Mild skin irritation or redness in very sensitive individuals
  • Rare allergic contact dermatitis for those with a specific fatty alcohol or fatty acid allergy
  • Temporary pore clogging or breakouts on extremely oily or acne prone skin when used in high concentrations
  • Eye irritation if a product containing the ester accidentally gets into the eyes

If any discomfort or adverse reaction occurs discontinue use and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1 / 5 (low)

C18-38 Alkyl C24-54 Acid Ester consists of very large waxy molecules that tend to stay on the skin surface instead of sinking into pores. Because it is less greasy than many plant oils it has a lower chance of trapping dead cells or triggering breakouts. That said products using very high levels of the ester may feel heavier on already oily skin which could contribute to congestion in rare cases.

Overall this ingredient is considered acceptable for most people who are prone to acne although extremely reactive or cystic skin types may still prefer lighter formulas.

Its non volatile waxy nature can slightly slow down the evaporation of sweat, so pairing it with good cleansing habits helps keep pores clear.

Summary

C18-38 Alkyl C24-54 Acid Ester is mainly added to cosmetics as a viscosity controller. By thickening the oil phase it keeps emulsions stable, gives creams a plush cushiony glide and lets sticks or balms stay solid yet melt smoothly on contact with skin. These perks come from its long chain fatty alcohol and fatty acid structure which forms a soft wax that spreads easily while sealing in moisture.

The ester is not as famous as ingredients like shea butter or jojoba oil but it appears in a steady range of moisturizers, sunscreens, lip care and hair products because formulators value its dependable texture boost and plant based origin.

Safety data shows a very low risk of irritation or allergy for most users. Still everyone’s skin is unique so it is smart to patch test any new product that features this ingredient before applying it all over.

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