What Is C5-6 Olefin/C8-10 Naphtha Olefin Copolymer?
C5-6 Olefin/C8-10 Naphtha Olefin Copolymer is a man-made ingredient created by joining together small hydrocarbon units called olefins that come from the lighter fractions of petroleum refining. The C5-6 part refers to molecules with five to six carbon atoms while the C8-10 part covers those with eight to ten. When these two groups are linked in a controlled reaction they form a smooth flexible plastic-like chain known as a copolymer. Chemists began exploring light olefin copolymers for cosmetics in the late twentieth century when the need grew for longer lasting makeup that stayed put in humid conditions. Since the raw materials are plentiful and the process is efficient the ingredient became a cost-effective way to improve wear.
Production starts with distilling crude oil to separate the C5-10 olefin streams. These streams are purified then fed into reactors where heat and special catalysts connect the small molecules into longer chains. Adjusting temperature pressure and time lets manufacturers fine-tune the weight and texture of the final copolymer so it meets cosmetic grade standards. Once formed the solid resin is cooled chipped and shipped to formulators.
Because it forms a clear flexible film this copolymer shows up in many makeup and skin care products. It is common in long wear mascaras eyeliners liquid lipsticks and foundations that promise smudge or transfer resistance. You may also find it in sunscreens to lock the active filters in place creamy moisturizers that claim lasting hydration sheet masks hair gels and even some body lotions that boast a silky finish.
C5-6 Olefin/C8-10 Naphtha Olefin Copolymer’s Cosmetic Benefits/Uses
This ingredient is valued mainly for one key job in a formula.
As a film forming agent it spreads over skin or hair then dries into a thin flexible layer. That invisible film helps makeup stay put by anchoring pigments, boosts water and sweat resistance, adds a smooth touch, reduces flaking, locks moisturizers and actives close to the surface and can lend a light glossy sheen without feeling heavy or sticky.
Who Can Use C5-6 Olefin/C8-10 Naphtha Olefin Copolymer
This film former is generally suitable for normal, dry, combination and even oily skin because it sits on the surface rather than soaking in. Very acne-prone users who react badly to any occlusive layer may want to monitor their skin when first trying it since the ingredient can create a tight seal that could trap sebum in some cases.
Because it is made from petroleum fractions and contains no animal-derived substances it is compatible with vegan and vegetarian lifestyles.
Current safety data shows no systemic absorption so products using this copolymer are considered low risk for people who are pregnant or breastfeeding. That said this is not medical advice and anyone who is expecting or nursing should show all skin care products to a health professional before use just to be safe.
The ingredient does not make skin more sensitive to sunlight and has no known effect on photosensitivity. It is also fragrance-free and inert so it rarely interferes with other common cosmetic actives.
Potential Side Effects/Adverse Reactions
Side effects from topical use of C5-6 Olefin/C8-10 Naphtha Olefin Copolymer vary by individual. The points below list potential reactions but most people will not experience them when the ingredient is used at the low levels typical of finished cosmetics.
- Temporary skin irritation or redness in sensitive individuals
- Mild clogged pores or blemishes in those very prone to acne due to the occlusive film
- Eye watering or stinging if the raw ingredient contacts the eye before it sets in a mascara or eyeliner
- Contact dermatitis triggered by residual monomer impurities in extremely rare cases
If any of these effects occur stop using the product and consult a qualified health professional.
Comedogenic Rating
Rating: 1 / 5. Although the copolymer forms an occlusive film on the surface it has a large molecular size and does not penetrate pores, so it is unlikely to lodge inside follicles and spark breakouts. Most formulas use it at low concentrations alongside lightweight carriers, which further limits any pore-clogging potential. Suitable for acne-prone skin in most cases, though extremely sensitive users may prefer lighter textures.
Because the ingredient is chemically inert it does not react with sebum or encourage bacterial growth. Its comedogenic impact can rise slightly in very rich products where heavy oils are also present, but on its own the risk remains minimal.
Summary
C5-6 Olefin/C8-10 Naphtha Olefin Copolymer is chiefly a film former: it glides over skin or hair then dries into a clear flexible layer that locks pigments and actives in place, boosts water resistance and leaves a smooth finish. This reliable performance explains why it shows up in long wear makeup, sunscreens and a handful of moisturizers, even if it is not a headline ingredient that shoppers recognize by name.
Current data rates the copolymer as low risk for irritation, sensitization and systemic absorption. It is considered non-comedogenic for most users and vegan friendly. Still, skin can behave unpredictably, so it is wise to patch test any new product containing this or any other unfamiliar component to make sure it plays nicely with your unique complexion.