What Is Bis(1-Methylheptyl) Maleate?
Bis(1-Methylheptyl) Maleate, also known by its chemical name Bis-(1-Methylheptyl)-2-Butenedioate, is an oil-like ester created by reacting maleic acid with branched-chain alcohols derived from synthetic or plant-sourced fatty alcohols. The resulting molecule has two long hydrocarbon tails that make it feel silky and spreadable on skin and hair. Although the compound itself is relatively modern, esters of maleic acid have been explored since the mid-20th century for their softening abilities in plastics and coatings. Cosmetic chemists later spotted its smooth, non-greasy texture and began adding it to beauty formulas in the early 2000s as a lighter alternative to traditional heavy oils.
Commercial production is straightforward: maleic anhydride is esterified with 1-methylheptanol under controlled heat in the presence of an acid catalyst, then purified to remove residual acid and alcohol. The finished ingredient is a clear, low-odor liquid that mixes easily with oils, silicones and many solvents, letting formulators fine-tune texture without cloudiness or stickiness.
You will most often see Bis(1-Methylheptyl) Maleate in lightweight facial moisturizers, hydrating hair masks, leave-in conditioners, anti-aging serums and color cosmetics like foundations or creamy blushes where a smooth, velvety slip is desired.
Bis(1-Methylheptyl) Maleate’s Cosmetic Benefits/Uses
This multi-tasking ester brings several practical advantages to a formula
- Hair conditioning: Coats the hair shaft with a thin flexible layer that smooths cuticles, boosts shine and reduces static so strands feel softer and more manageable
- Plasticiser: Softens film formers in styling products, mascaras and long-wear makeup letting them flex with skin or hair instead of cracking or flaking
- Emollient: Glides across the skin filling in microscopic gaps in the surface to leave it feeling silky, supple and comfortably hydrated without heaviness
- Solvent: Helps dissolve and evenly disperse oil-soluble ingredients such as pigments, UV filters and fragrances improving stability and consistency
Who Can Use Bis(1-Methylheptyl) Maleate
Because this ester feels light and non greasy it fits well with most skin types including dry, normal, combination and even oily complexions that dislike heavier oils. Its smooth texture rarely clogs pores so it can be an option for acne-prone users, though anyone who knows they react easily to esters or maleic acid derivatives should approach with caution. The ingredient is generally considered non irritating for hair and scalp, making it suitable for all hair textures from fine to coily.
Bis(1-Methylheptyl) Maleate is synthesised from plant sourced or fully synthetic alcohols and maleic anhydride, neither of which come from animals. That means products relying on this ester are typically vegan and vegetarian friendly as long as the rest of the formula also avoids animal by-products.
No reproductive toxicity has been linked to topical use of this ingredient, so products containing it are not automatically off limits during pregnancy or breastfeeding. That said, this is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of any cosmetic to their doctor before use.
The molecule does not absorb UV light and does not make skin more sensitive to the sun, so it is not considered photosensitising. It also plays nicely with common actives such as retinoids, niacinamide and vitamin C, adding slip without interfering with their performance.
Potential Side Effects/Adverse Reactions
Responses to any cosmetic ingredient can vary from person to person. The points below list potential reactions that could occur with Bis(1-Methylheptyl) Maleate, but they are unlikely for the average consumer when the product is formulated and used as directed.
- Mild skin redness or stinging in very sensitive individuals
- Contact dermatitis in users allergic to maleic acid esters
- Temporary eye irritation if the product accidentally gets into the eyes
- Rare acne flare in people highly prone to breakouts
If any discomfort or unexpected reaction develops stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1 / 5. Bis(1-Methylheptyl) Maleate is a lightweight branched ester that spreads thinly and absorbs without leaving a heavy residue. Its molecular structure is too bulky to pack tightly inside pores so it is less likely to trap dead skin or sebum compared with richer straight-chain oils. Formulators typically use it at modest levels—which also keeps pore-blocking potential low. For most people this makes the ingredient suitable even if you are prone to acne or frequent breakouts. Because it can help dissolve heavier oils it may actually improve the feel of thicker formulas. Only extremely sensitive or very oily skin types might notice an occasional clogged pore when the ingredient is used at high concentrations.
Summary
Bis(1-Methylheptyl) Maleate works behind the scenes as an emollient that fills in tiny surface gaps, a hair-conditioning agent that smooths cuticles, a plasticiser that keeps makeup films flexible and a solvent that helps pigments or UV filters stay evenly dispersed. These combined talents give products a silky slip and longer-lasting comfort without greasiness.
It is not a headline ingredient like hyaluronic acid or vitamin C so you will not see it splashed across marketing copy, yet chemists appreciate it for creating that luxurious feel consumers notice the moment a product glides on. As a result its use is quietly rising in modern lightweight creams, serums and hair treatments.
Safety data show low irritation and sensitisation risk when used as directed. Still, every skin is unique so it is smart to perform a quick patch test whenever you try a new formula containing this ester.