C24-28 Alkyl Methicone: 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 C24-28 Alkyl Methicone?

C24-28 Alkyl Methicone is a type of silicone made by attaching long waxy chains of 24 to 28 carbon atoms to a siloxane backbone. These added chains give the molecule a soft slip and richer feel than classic lightweight silicones like dimethicone. The raw materials usually begin with silica, which is converted into siloxane units, then reacted with high-purity fatty alcohols derived from vegetable oils or synthetic sources. The result is a semi-fluid silicone that spreads easily yet leaves a cushioned, non-greasy finish.

Silicones entered cosmetics in the 1950s for their silky touch and water-resistant properties. As formulators looked for new textures, chemists developed alkyl-modified versions in the 1990s to blend the best of silicones and natural oils. C24-28 Alkyl Methicone became popular because its longer carbon chain offers a richer feel without heavy residue.

You will most often find this ingredient in leave-on skin care such as moisturizers, night creams, anti-aging serums, sunscreens and BB creams. It is also used in solid or balm textures, stick foundations, hair-smoothing creams and creamy face masks where a velvety finish and improved spreadability are desired.

C24-28 Alkyl Methicone’s Cosmetic Benefits/Uses

This versatile silicone supports both product texture and skin feel in several ways

  • Skin conditioning: Forms a breathable layer that smooths rough spots and leaves skin feeling soft and supple which can enhance overall comfort and radiance
  • Emollient: Provides quick slip during application then settles into a lightweight cushion that helps reduce transepidermal water loss so skin feels moisturized longer without an oily film
  • Viscosity controlling: Adjusts thickness and improves spreadability allowing creams or lotions to glide on evenly and stay stable over time

Who Can Use C24-28 Alkyl Methicone

C24-28 Alkyl Methicone is generally well tolerated by all skin types. Its silky yet breathable film suits dry and mature skin that needs extra cushioning while the dry-touch finish makes it comfortable for normal, combination and even oily skin that dislikes greasy residue. Highly sensitive or reactive complexions usually accept this silicone because it is non-penetrating and free of fragrance and preservatives, but anyone with a known silicone sensitivity should proceed with caution.

The ingredient is synthesized from silica and long-chain fatty alcohols that are most often sourced from plants or produced in a laboratory. No animal-derived components are required, so products formulated with C24-28 Alkyl Methicone are typically compatible with vegan and vegetarian lifestyles. As always, certification or a direct statement from the brand provides the final confirmation.

C24-28 Alkyl Methicone is considered chemically inert and does not cross the skin barrier, so it is not expected to pose a risk during pregnancy or while breastfeeding. This is not medical advice and anyone who is pregnant or nursing should review their entire skin care routine with a qualified health professional before use.

The molecule does not absorb UV light and therefore does not cause photosensitivity. It can actually improve the spread of sunscreens by helping them glide evenly.

Potential Side Effects/Adverse Reactions

Reactions to topical C24-28 Alkyl Methicone differ from person to person. The effects listed below are possible yet unlikely when the ingredient is used at cosmetic levels in a well-formulated product.

  • Mild skin congestion very acne-prone users may notice clogged pores if the product is not removed thoroughly
  • Rare contact irritation a small number of individuals can experience redness itching or discomfort due to personal sensitivity to silicones
  • Product buildup heavy layering without proper cleansing can leave a film that dulls skin or weighs down hair
  • Reduced penetration of actives the breathable barrier may slightly slow the absorption of water-based serums applied afterward

If you notice persistent irritation or breakouts stop using the product and consult a dermatologist or healthcare professional for guidance.

Comedogenic Rating

Rating: 1 out of 5

The large silicone backbone keeps C24-28 Alkyl Methicone sitting on the skin surface while its long alkyl chains provide slip without sinking into pores. This configuration makes it far less likely to trap debris compared with heavier natural oils or waxes. That said ultra acne-prone users who react to almost any occlusive film might still prefer lighter textures.

Overall it is considered suitable for breakout-prone skin when used in well-balanced formulas.

Cleansing thoroughly at the end of the day helps prevent any potential buildup that could contribute to congestion over time.

Summary

C24-28 Alkyl Methicone acts as a skin-conditioning emollient that smooths rough patches cushions the complexion and locks in moisture with a weightless feel. It also fine-tunes viscosity so creams spread evenly and stay stable during shelf life. Thanks to this mix of performance and sensory appeal the ingredient shows up frequently in modern moisturizers primers hybrid sunscreens and hair styling products though it is still less ubiquitous than classic dimethicone.

Safety data and decades of silicone use point to a low risk of irritation sensitization or toxicity when applied topically. Still every skin is unique so it is smart to patch test any new product containing this or other silicones before full use.

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