Isododecane: Comedogenic Rating & Ingredient Analysis
Isododecane is a lightweight, fast-evaporating emollient that gives modern makeup and skincare their weightless, long-wearing feel. It is a volatile hydrocarbon, meaning it spreads a product effortlessly over the skin and then evaporates, leaving behind the pigments, film-formers or actives it carried without any greasy residue. This is why it is a backbone of long-wear liquid lipsticks, transfer-resistant foundations and quick-absorbing primers. It is a plant- or petroleum-derived alternative to volatile silicones like cyclopentasiloxane, and brands increasingly choose it for a similar silky slip with a different environmental profile.
Quick facts
- Comedogenic rating
- our estimate — not measured
- Irritation risk
- Low
- Effective pH
- —
- Typical strength
- 5–40%
- Pregnancy
- Considered safe
- Suits skin types
- oilycombinationnormalacne-pronesensitive
Where this number comes from
No one has published a comedogenic rating for this ingredient. Fulton's 1989 table tested about 250 raw materials and this was not among them, and we found no later study measuring it. The figure shown is our own reasoning from the ingredient's chemistry and how it is used — treat it as an estimate, not a measurement.
Fulton read his own scale as 0-1 not significant, 2-3 borderline, 4-5 positive. The assay is the rabbit ear at 10% dilution, which the paper itself calls extremely sensitive and not fully predictive of human skin. Ratings describe the raw ingredient; concentration and formulation change real-world behaviour.
Caution profile
The four published fields on this page, on one 0–5 scale. Further from the centre means more care is needed — never that the ingredient is worse.
Derived, not measured: pore-clogging is the published comedogenic rating; irritation maps low/moderate/high to 1/3/5; pregnancy maps safe/caution/avoid to 0/3/5; skin-type limits is how many of the seven skin types this entry does NOT list. Every input is printed in words in the quick-facts card above.
Show the numbers
| Metric | 0–5 | Published field |
|---|---|---|
| Pore-clogging | 0 | 0/5 |
| Irritation | 1 | Low |
| Skin-type limits | 1.4 | 5/7 |
| Pregnancy | 0 | Considered safe |
Working pH and typical strength
Where this ingredient is formulated to sit, and at what concentration.
Both bars come from the fields above: the pH window and the typical strength range published for this ingredient. The tinted column is healthy skin's surface pH (about 4.7–5.75).
Show the numbers
| Metric | 0–5 |
|---|---|
| Typical strength | 5–40% |
What is it?
Isododecane is a branched-chain saturated hydrocarbon with twelve carbon atoms, engineered to be volatile so that it flashes off the skin after application. Its job is mechanical rather than active: it thins and spreads a formula, improves how evenly pigments deposit, and then evaporates to leave a dry, comfortable finish. Because it is non-polar and volatile, it is prized in waterproof and long-wear products, where the residue left after evaporation clings well and resists smudging. It is chemically inert, does not penetrate meaningfully, and is a common substitute for cyclopentasiloxane in silicone-free formulas, often paired with dimethicone or polybutene for the desired feel.
Benefits
Lightweight, non-greasy feel
Isododecane evaporates after spreading, so products glide on easily and dry to a weightless finish that suits oily and acne-prone skin.
Enables long wear
By flashing off and leaving pigments and film-formers behind, it underpins transfer-resistant lipsticks and foundations that last through the day.
Excellent spreadability
It thins formulas and helps them apply evenly, improving how pigments deposit and how primers and sunscreens layer under makeup.
Silicone-free option
It gives a silky slip similar to cyclopentasiloxane, letting brands build silicone-free formulas alongside emollients like squalane.
How to use
You will meet isododecane inside finished products rather than on its own: long-wear foundations, liquid lipsticks, primers, mascaras and some sunscreens. Use these as directed; the light, quick-drying feel is the point. Because volatile emollients can feel drying on very dry skin once they evaporate, follow makeup with a moisturizer if needed, and choose products that also contain lasting emollients like squalane or dimethicone. Isododecane sits on the surface and removes best with an oil-based cleanser, especially in waterproof formulas.
Side effects
Isododecane is inert and very well tolerated, with a low irritation profile and a comedogenic rating around zero, so it rarely contributes to breakouts. Its main practical trait is that, as a volatile solvent, it can feel slightly drying on already dry or compromised skin once it evaporates. It does not carry the systemic or hormonal concerns of some other ingredient classes. Waterproof formulas built on it need thorough removal to avoid buildup.
Who should avoid it
There is no group that needs to avoid isododecane on safety grounds; it is considered acceptable in pregnancy and suits sensitive and acne-prone skin. People with very dry skin may find volatile-heavy formulas feel tight and prefer richer textures. Anyone who struggles to remove long-wear makeup should use a dedicated oil cleanser.
Pairs well with
Frequently asked questions
What does isododecane do in makeup?
It spreads the product smoothly and then evaporates, leaving pigments and film-formers behind. This gives a lightweight feel and long, transfer-resistant wear.
Is isododecane the same as silicone?
No. It is a volatile hydrocarbon used as a silicone-free alternative to cyclopentasiloxane, giving a similar light, silky slip through different chemistry.
Does isododecane clog pores?
No. It has a comedogenic rating near zero and evaporates off the skin, so it rarely contributes to congestion even in acne-prone skin.
Can isododecane dry out my skin?
As a volatile solvent it can feel slightly drying on very dry skin once it evaporates, so follow up with a moisturizer containing squalane or dimethicone if needed.
Sources & further reading
Medical disclaimer
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