C24-28 Alkyl Dimethicone: 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 C24-28 Alkyl Dimethicone?

C24-28 Alkyl Dimethicone is a silicone-based ingredient created by joining long chain waxy alcohols that range from 24 to 28 carbon atoms with dimethicone, a lightweight silicone oil. The result is a hybrid material that blends the silky feel of silicones with the cushioning richness of natural waxes. It was first explored in the late 1990s as chemists searched for ways to give silicone ingredients a softer, more velvety touch. Manufacturers make it through a controlled reaction that bonds the alkyl groups to the silicone backbone, then purify the mixture into a smooth, low odor fluid.

Because it bridges the gap between oil and silicone, C24-28 Alkyl Dimethicone slips easily into many cosmetic formulas. You will often see it in leave-on face creams, anti-aging serums, sunscreens, hair conditioners, makeup primers and rinse-off masks where it helps the product glide on, stay even and feel luxurious.

C24-28 Alkyl Dimethicone’s Cosmetic Benefits/Uses

This ingredient delivers several practical perks to modern beauty products.

  • Skin Conditioning: It forms a breathable layer on the skin that locks in moisture, smooths rough spots and leaves a soft, non-greasy finish which boosts overall comfort and slip
  • Viscosity Controlling: It thickens or thins a formula as needed, giving chemists precise control over texture so creams feel plush, lotions stay light and makeup spreads without streaks

Who Can Use C24-28 Alkyl Dimethicone

C24-28 Alkyl Dimethicone is gentle enough for most skin types. Dry and normal skin enjoy its moisture-sealing touch while oily and combination skin appreciate its light feel that does not leave a greasy film. Sensitive skin usually tolerates it because it is chemically stable and non-reactive, though anyone with a known silicone sensitivity should steer clear.

The ingredient is made from man-made silicones and plant-sourced or synthetic fatty alcohols, with no animal by-products. For that reason it is suitable for vegans and vegetarians.

Pregnant or breastfeeding women are not known to face special risks from topical use of this silicone. It stays on the surface and is not absorbed to a meaningful degree. Still, this is not medical advice and anyone expecting or nursing should check with a doctor before adding new skincare to their routine.

C24-28 Alkyl Dimethicone does not make skin more sensitive to sunlight so it is safe for daytime wear. It also plays well with most other cosmetic ingredients and does not affect SPF performance.

Potential Side Effects/Adverse Reactions

Responses to C24-28 Alkyl Dimethicone vary from person to person. The points below list uncommon but possible effects. When the ingredient is used correctly in a well-formulated product most people will not notice any of these issues.

  • Mild skin irritation such as redness or itching in those sensitive to silicones
  • Temporary clogged pores or breakouts in very acne-prone skin if layered with heavy occlusive products
  • Product buildup that may dull hair or skin if cleansers are not removing residue fully
  • Rare allergic contact dermatitis presenting as rash or swelling

If any unwanted reaction occurs stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1 / 5 – C24-28 Alkyl Dimethicone sits on the surface and has a breathable structure similar to dimethicone, so it rarely blocks pores. The added long-chain alkyl groups give a richer feel than straight silicones, yet the molecule is still too large and inert to sink into follicles and cause widespread congestion. For this reason it is generally suitable for people who break out easily, especially when used in lightweight formulas. Those extremely sensitive to any occlusive film may still prefer to limit heavy layering of silicone-rich products.

Because it is non-sticky and easy to cleanse with a standard face wash, residue that could trap impurities is unlikely to build up as long as regular cleansing habits are followed.

Summary

C24-28 Alkyl Dimethicone works as a skin conditioner and viscosity controller. It lays down a thin, silky veil that locks in water, smooths texture and boosts slip while also helping chemists fine-tune the thickness of creams, lotions and makeup. This dual role comes from its hybrid structure: the silicone backbone provides glide and breathability while the fatty alkyl side chains add soft cushion and gentle thickening power.

Although not as famous as plain dimethicone, it appears in a growing number of modern moisturizers, primers and sunscreens where a luxurious yet lightweight finish is desired. It enjoys a safe track record with very low irritation and comedogenic risk, making it a reliable pick for most skin types. As with any new cosmetic, give your skin a chance to adjust by patch testing a small area before full use.

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