Ingredient review
Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone
INCI: BIS-C16-18 ALKYL GLYCERYL UNDECYL DIMETHICONE
A gentle silicone emollient that improves product texture and leaves skin feeling smooth without clogging pores.
In plain English
This is a type of silicone that's been modified with fatty alcohols and glycerin to make it more compatible with skin. It sits on the surface of your skin, filling in tiny gaps to create a smooth, soft feel. It doesn't absorb deeply, so it's mainly used to improve how a product spreads and how it feels when you apply it.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone is generally a lower-concern ingredient when the full formula suits your skin.
Plain-English read
Treat this as a practical screening step before you compare products that contain this ingredient.
- Step 1Start with the score, then check the irritation and clogging risk before judging Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.
Score terms in plain English
Irritation risk
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A synthetic silicone polymer combined with cetyl/stearyl alcohol and glycerin-derived groups, designed to act as a lightweight emollient and skin conditioner.
How it works
It forms a thin, breathable film on the skin's surface that reduces friction, helps other ingredients spread evenly, and leaves a silky, non-greasy finish. It also helps stabilize emulsions and can improve the water-resistance of sunscreens.
Pros
Silky texture without grease
Creates a smooth, velvety feel on skin that helps makeup and sunscreen apply evenly, without leaving a heavy or oily residue.
Low irritation potential
Rated low for both irritation and comedogenicity, making it suitable for sensitive and acne-prone skin types.
Cons and cautions
Possible buildup over time
Like many silicones, it can accumulate on skin or hair if not thoroughly cleansed, potentially leading to dullness or clogged pores for some users.
Not biodegradable
As a synthetic silicone, it does not break down easily in the environment, which may be a concern for eco-conscious consumers.
Best for
- People with normal to dry skin who want a smooth, non-greasy finish
- Anyone using makeup primers or sunscreens that need even application
Use caution if
- Those who strictly avoid all silicones in their routine
Usage tips
Safety summary
Generally recognized as safe for topical use in cosmetics. Low irritation and comedogenic scores. No significant safety concerns at typical concentrations.
Research notes
Limited independent studies on this specific molecule, but it is structurally similar to other well-studied dimethicone derivatives that are considered safe and non-irritating.
Common label clues
- Typical concentration
- 0.5% to 5%
- Regulatory status
- Approved for use in cosmetics in the US (FDA), EU, and many other regions. No specific restrictions at typical use levels.
- Common uses
- Moisturizers, Serums, Sunscreens, Makeup primers
- Environmental note
- Silicones like this one are not biodegradable and can persist in water systems. Some brands are moving toward biodegradable alternatives.
Good to know
- This ingredient is often found in 'silicone blend' primers and long-wear foundations for its film-forming ability.
- It is considered safe by major regulatory bodies when used in typical cosmetic concentrations.
Common questions
What is Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone in beauty products?
This is a type of silicone that's been modified with fatty alcohols and glycerin to make it more compatible with skin. It sits on the surface of your skin, filling in tiny gaps to create a smooth, soft feel. It doesn't absorb deeply, so it's mainly used to improve how a product spreads and how it feels when you apply it.
What does Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone do in a beauty product?
It forms a thin, breathable film on the skin's surface that reduces friction, helps other ingredients spread evenly, and leaves a silky, non-greasy finish. It also helps stabilize emulsions and can improve the water-resistance of sunscreens.
Is Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone safe for most people?
Generally recognized as safe for topical use in cosmetics. Low irritation and comedogenic scores. No significant safety concerns at typical concentrations.
Who should be careful with Bis-C16-18 Alkyl Glyceryl Undecyl Dimethicone?
Those who strictly avoid all silicones in their routine
Research sources
Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.