C26-28 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 C26-28 Alkyl Dimethicone?

C26-28 Alkyl Dimethicone is part of the silicone family, a group of ingredients built on a chain of silicon and oxygen atoms. In this case the backbone is linked to long waxy chains made of 26 to 28 carbon atoms, which gives it a soft buttery feel that sets it apart from lighter silicones like dimethicone. These long chains help it spread smoothly while leaving a light, non-greasy film on skin and hair.

Most cosmetic grade C26-28 Alkyl Dimethicone starts with quartz-derived silica that is turned into siloxane fluid. Chemists then attach the C26-C28 alkyl groups through a controlled reaction called alkylation. The resulting material is purified, checked for consistency then blended into finished formulas.

Silicones began showing up in beauty products in the 1950s for their silky touch. The need for richer textures without heaviness led to the development of alkyl-modified versions in the 1990s. C26-28 Alkyl Dimethicone quickly found favor because it delivers cushion and softness yet still feels breathable.

You will most often spot it in leave-on hair masks, anti-frizz creams, deep conditioners, facial moisturizers, night creams, hand lotions, lip balms and protective balms for rough spots. It is also used in color cosmetics like foundations and lipsticks to improve glide and wear.

C26-28 Alkyl Dimethicone’s Cosmetic Benefits/Uses

Formulators choose this ingredient for two main reasons that both center on feel and conditioning performance.

  • Hair Conditioning: It coats strands with a thin flexible layer that smooths cuticles, boosts shine and makes detangling easier. Because it is heavier than standard dimethicone it helps calm frizz and flyaways in thick or textured hair without making hair look oily.
  • Skin Conditioning: On skin it forms a breathable shield that traps moisture, leaving a soft velvety finish. This helps reduce rough patches and gives creams a luxurious slip that makes them pleasant to apply.

Who Can Use C26-28 Alkyl Dimethicone

This silicone suits most skin types. Dry and mature skin tends to love the cushioning film it leaves, while normal or combination skin usually enjoys the silky slip without feeling greasy. Those with very oily or acne-prone skin might find the richer texture too occlusive if layered heavily, so lighter application or rinse-off products may feel more comfortable.

C26-28 Alkyl Dimethicone is synthesized in a lab from mineral-based raw materials so it contains no animal derivatives. Because of that it is generally acceptable for both vegans and vegetarians, though final product cruelty policies depend on the brand.

The molecule is large and stays on the surface of skin rather than being absorbed, so it is considered low risk for pregnant or breastfeeding women. This information is not medical advice and anyone who is expecting or nursing should clear all skincare choices with a doctor first.

The ingredient does not heighten photosensitivity and it plays nicely with sunscreen filters. It is also compatible with common actives like vitamin C, retinoids and niacinamide.

Potential Side Effects/Adverse Reactions

Reactions to topical C26-28 Alkyl Dimethicone differ from person to person. The effects listed below are possible but uncommon when products are formulated and used as intended.

  • Buildup on hair that leads to limp or dull strands if shampooed infrequently
  • Temporary clogged pores or milia in individuals prone to congestion when layered thickly
  • Mild skin or scalp irritation in rare cases of sensitivity to silicones
  • Contact dermatitis triggered by impurities or other formula components rather than the silicone itself

If any irritation or unwanted reaction develops stop using the product and seek guidance from a healthcare professional.

Comedogenic Rating

Rating: 1/5 — C26-28 Alkyl Dimethicone sits on top of skin rather than sinking into pores, and its molecules are too large to plug follicle openings easily. While the longer alkyl chains make it richer than classic dimethicone, it is still classed as low clogging because it forms a breathable film that can be washed away with routine cleansing.

Most people prone to acne can use it without problems, though very heavy layering or infrequent cleansing could add to surface buildup in some cases.

If used in hair products, residue that drifts onto facial skin may contribute to congestion for a tiny minority, so washing the hairline well can help.

Summary

C26-28 Alkyl Dimethicone conditions hair by coating strands with a silky shield that smooths cuticles, tames frizz and adds shine. On skin it locks in moisture and leaves a soft velvet feel that makes creams glide on easily. It delivers these perks thanks to its silicone backbone combined with long waxy carbon chains that create a flexible, non-greasy film.

It is not as famous as everyday dimethicone yet has carved out a niche in richer leave-on creams, styling balms and lip products where extra cushion is prized.

The ingredient is considered low risk, free of major safety flags and suitable for most skin types including sensitive. As with any new cosmetic it is wise to perform a quick patch test to rule out personal irritation before full use.

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