What Is Isobutylene/Sodium Maleate Copolymer?
Isobutylene/Sodium Maleate Copolymer is a synthetic polymer made by linking together isobutylene, a light hydrocarbon, with the disodium salt of maleic acid. The result is a long, flexible chain that dissolves in water and can create thin, invisible films on the skin or hair. First developed for industrial coatings in the mid-20th century, chemists soon noticed its smooth feel and excellent film-forming ability, which led to its adoption in personal care products during the 1980s.
To manufacture it, producers blend purified isobutylene gas with maleic anhydride, then neutralize the mix with sodium hydroxide. The blend is polymerized under heat and pressure until it forms a stable water-soluble powder or viscous solution. After purification and drying, the polymer is ready to be added to cosmetic formulas.
You can find Isobutylene/Sodium Maleate Copolymer in sheet masks, peel-off masks, serums, lightweight gel moisturizers, hair-setting sprays, anti-aging creams and long-wear makeup. It is valued wherever a smooth, flexible film or a controlled product thickness is needed.
Isobutylene/Sodium Maleate Copolymer’s Cosmetic Benefits/Uses
This ingredient plays more than one role in modern formulations
- Film Forming: Creates a breathable layer that locks in moisture, helps active ingredients stay on the skin longer and improves the wear time of makeup or hair products
- Viscosity Controlling: Adjusts the thickness of lotions, gels or sprays so they spread evenly and feel pleasant without being runny or too sticky
Who Can Use Isobutylene/Sodium Maleate Copolymer
Because it is lightweight and non-occlusive, Isobutylene/Sodium Maleate Copolymer is generally suitable for all skin types including oily, combination, dry and sensitive skin. It does not clog pores and has a low likelihood of causing redness or tightness, so even reactive or acne-prone users usually tolerate it well. There are no known skin types that must avoid the ingredient unless a specific personal allergy exists.
The polymer is made entirely from petrochemical and mineral sources with no animal-derived components, so products that rely on it are typically vegan and vegetarian friendly. As always, check the rest of the ingredient list to confirm the whole formula meets individual lifestyle standards.
No data suggest that topical use poses risks for pregnant or breastfeeding women when the product is used as directed. Still, this is not medical advice and anyone who is expecting or nursing should review new skincare with a qualified health professional to be safe.
Isobutylene/Sodium Maleate Copolymer does not increase photosensitivity. Normal sun protection practices are sufficient while using products that contain it.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient can vary from person to person. The points below outline potential issues users could encounter, though they are uncommon when the polymer is formulated and used correctly.
- Mild skin irritation – slight redness or itching in individuals with extremely sensitive skin
- Contact dermatitis – rare allergic reaction triggered by the polymer itself or by residual manufacturing impurities
- Eye irritation – temporary stinging or watering if a product containing the polymer accidentally gets into the eyes
- Build-up on hair – with very frequent use in styling sprays the film may accumulate leaving hair feeling coated until washed out
If any discomfort or unexpected reaction occurs discontinue use and seek medical advice if symptoms persist or worsen.
Comedogenic Rating
Rating: 0 / 5 (non-comedogenic)
Isobutylene/Sodium Maleate Copolymer is water soluble and contains no heavy oils or waxes that can block pores. The thin breathable film it creates sits on the surface then rinses away easily with regular cleansing so it rarely traps sebum or debris. Because of these factors it is considered non-comedogenic and is generally suitable for people who are prone to acne or frequent breakouts.
As with any ingredient overall formula matters. A product packed with rich oils could still clog pores even if this polymer is present so look at the full ingredient list when choosing skincare.
Summary
Isobutylene/Sodium Maleate Copolymer is mainly used to form a flexible film on skin or hair and to fine-tune the thickness of lotions gels sprays and makeup. The water soluble polymer links together in solution to lay down an invisible mesh that locks in moisture holds active ingredients in place and improves wear time while also adding just the right slip and body to the formula.
It is not the trendiest name on a label but formulators appreciate its reliable performance so it quietly appears in many long-wear cosmetics sheet masks and styling products.
Safety studies show a very low risk of irritation or clogged pores making it a friendly option for most users. Still skin can be unpredictable so it is smart to patch test any new product that contains this or any other unfamiliar ingredient.