Bis-Benzyl Undecanoate 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 23, 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 Bis-Benzyl Undecanoate Dimethicone?

Bis-Benzyl Undecanoate Dimethicone is a specialty silicone created by attaching benzyl undecanoate groups to a dimethicone backbone. Dimethicone itself is a smooth, flexible polymer made of repeating siloxane units, well known in skincare for its silky feel and protective properties. Chemists tweak standard dimethicone by bonding it with natural-origin undecanoic acid and benzyl alcohol, giving the finished molecule extra conditioning power and a slightly richer touch.

The ingredient was developed in the early 2000s, when formulators looked for a silicone that could deliver the familiar glide of dimethicone while also improving skin softness without leaving a heavy film. By reacting dimethicone chains with the modified fatty acid under controlled heat and using a catalyst, manufacturers produce a fluid that blends effortlessly into oil or silicone phases of cosmetic mixtures.

You will spot Bis-Benzyl Undecanoate Dimethicone in face primers, lightweight moisturizers, anti-aging serums, sheet mask essences, sun care products and some cream foundations. Its ability to fine-tune texture makes it popular in products that need to feel elegant yet still cushion and smooth the skin.

Bis-Benzyl Undecanoate Dimethicone’s Cosmetic Benefits/Uses

This ingredient earns its place on an ingredient list thanks to the way it improves both the feel and performance of a formula.

  • Skin conditioning – forms a breathable layer that softens rough patches, enhances slip and leaves skin feeling velvety
  • Viscosity controlling – helps adjust thickness so creams spread evenly, prevents watery products from feeling runny and keeps thicker ones from feeling greasy

Who Can Use Bis-Benzyl Undecanoate Dimethicone

This silicone derivative is considered gentle and generally suits all major skin types including normal, dry, combination and oily. Its lightweight breathable film rarely feels heavy or occlusive so even acne-prone or sensitive skin tends to tolerate it well. Those with very reactive skin should still keep an eye on how their skin responds as with any new ingredient.

Bis-Benzyl Undecanoate Dimethicone is synthesized from silicone, benzyl alcohol and plant-derived undecanoic acid so it contains no animal parts or by-products. Manufacturing does not rely on animal processing which makes it acceptable for vegan and vegetarian lifestyles.

Current safety data show no specific risks for pregnant or breastfeeding women when the ingredient is used topically at levels seen in cosmetics. This is not medical advice and anyone who is expecting or nursing should confirm any skincare routine with a qualified health professional to be completely certain.

The molecule is not known to increase photosensitivity. Regular daytime sunscreen habits remain important, but you do not need extra sun precautions solely because a product contains this silicone.

Potential Side Effects/Adverse Reactions

Reactions to topical Bis-Benzyl Undecanoate Dimethicone can differ from person to person. The points below outline possible but uncommon issues. When formulated correctly most users will not notice any of these effects.

  • Mild transient redness
  • Itching or stinging on very sensitive skin
  • Contact dermatitis in individuals already allergic to benzyl groups or silicones
  • Follicular blockage leading to small breakouts in those extremely prone to congestion

If irritation or any unwanted reaction appears stop using the product and seek advice from a healthcare professional if symptoms persist or worsen.

Comedogenic Rating

Rating: 1/5 (very low)

Bis-Benzyl Undecanoate Dimethicone is a large surface-coating silicone that spreads in an ultrathin layer and allows normal moisture exchange, so it rarely traps oil or dead cells inside pores. Most people, even those prone to blackheads or whiteheads, find it non-clogging. Only extremely oily skin that reacts to any film-forming ingredient might notice occasional congestion.

Summary

Bis-Benzyl Undecanoate Dimethicone is a specialty silicone that conditions skin and calibrates viscosity, delivering a smooth cushioned feel while helping formulas stay stable and spreadable. It shows up most in primers, sunscreens and lightweight lotions, though it is still less common than standard dimethicone.

Current data place it in the low-risk category for irritation or pore blockage, so everyday use is generally safe. Still, trying a small patch first is always wise when you add any new ingredient to your routine.

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