Ingredient review
C9-10 Alkane/Cycloalkane
INCI: C9-10 ALKANE/CYCLOALKANE
A lightweight, volatile hydrocarbon that helps dissolve makeup and sebum without leaving a greasy residue.
In plain English
C9-10 Alkane/Cycloalkane is a mix of hydrocarbon molecules (9 to 10 carbons long) that evaporate quickly on the skin. It works like a gentle solvent to break down oil-based makeup and sunscreen, and it leaves a silky, non-greasy feel. Because it's volatile, it doesn't stay on the skin long, making it a popular alternative to heavier oils or silicones.
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
C9-10 Alkane/Cycloalkane 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 C9-10 Alkane/Cycloalkane.
- 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 blend of linear and cyclic hydrocarbons with 9 to 10 carbon atoms, derived from petroleum refining. It is clear, odorless, and evaporates quickly.
How it works
When applied, it spreads easily and dissolves oil-based impurities. As it evaporates, it leaves behind a thin, non-sticky film that can help other ingredients absorb or spread more evenly.
Pros
Lightweight and fast-evaporating
It spreads easily and disappears quickly, so you don't feel a heavy layer on your skin.
Effective at dissolving oil-based products
It breaks down waterproof makeup and sunscreen without harsh scrubbing, reducing friction on the skin.
Cons and cautions
Petroleum-derived
It is a synthetic hydrocarbon from petroleum, which some consumers prefer to avoid for environmental or personal reasons.
May be drying for some
Because it evaporates, it can take some natural oils with it, potentially leaving very dry skin feeling tight.
Best for
- People who wear heavy or waterproof makeup and want a gentle remover
- Those with oily or combination skin who prefer lightweight, non-greasy textures
Use caution if
- Individuals with very dry or compromised skin barriers may find it slightly drying
Usage tips
Safety summary
C9-10 Alkane/Cycloalkane is considered safe for use in cosmetics at typical concentrations. It has low skin irritation and sensitization potential. Inhalation of spray products containing it should be minimized.
Research notes
Safety assessments by the Cosmetic Ingredient Review (CIR) panel have concluded that similar hydrocarbon blends are safe in leave-on and rinse-off products when formulated properly. No significant human or animal toxicity has been reported at cosmetic use levels.
Common label clues
- Typical concentration
- 1–30%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. No specific concentration limits are imposed, but formulators typically keep it under 30%.
- Common uses
- Makeup removers, Cleansing oils, Sunscreens, Hair oils
- Environmental note
- As a petroleum-derived hydrocarbon, its production has a carbon footprint. However, it is not classified as a bioaccumulative or persistent environmental pollutant.
Good to know
- This ingredient is often listed as 'C9-10 Isoparaffin' on older labels.
- It is considered a volatile silicone alternative in 'silicone-free' formulations.
Common questions
What is C9-10 Alkane/Cycloalkane in beauty products?
C9-10 Alkane/Cycloalkane is a mix of hydrocarbon molecules (9 to 10 carbons long) that evaporate quickly on the skin. It works like a gentle solvent to break down oil-based makeup and sunscreen, and it leaves a silky, non-greasy feel. Because it's volatile, it doesn't stay on the skin long, making it a popular alternative to heavier oils or silicones.
What does C9-10 Alkane/Cycloalkane do in a beauty product?
When applied, it spreads easily and dissolves oil-based impurities. As it evaporates, it leaves behind a thin, non-sticky film that can help other ingredients absorb or spread more evenly.
Is C9-10 Alkane/Cycloalkane safe for most people?
C9-10 Alkane/Cycloalkane is considered safe for use in cosmetics at typical concentrations. It has low skin irritation and sensitization potential. Inhalation of spray products containing it should be minimized.
Who should be careful with C9-10 Alkane/Cycloalkane?
Individuals with very dry or compromised skin barriers may find it slightly drying
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.