What Is Triisotridecyl Trimellitate?
Triisotridecyl Trimellitate is an ester made from trimellitic acid and branched-chain isotridecyl alcohols. Chemically it sits in the family of trimellitate esters, which are known for their lubricating feel and stability. The isotridecyl part of the molecule comes from petroleum-derived fatty alcohols that are carefully processed to create a uniform chain length, while trimellitic acid is produced from oxidized aromatic compounds. When these two components are reacted under heat in the presence of a catalyst, water is removed and the smooth, oily ester is formed.
This ingredient first gained attention in the 1970s as chemists looked for replacements for heavier mineral oils in personal care. Its low viscosity and strong resistance to oxidation made it attractive for long-wear makeup and skin care formulations. Over time, formulators discovered that it offers a silky feel without being overly greasy, leading to its wider use in modern cosmetics.
Today you will most often find Triisotridecyl Trimellitate in color cosmetics like lipsticks, long-wear foundations and eye products, where it helps pigments glide on evenly. It is also common in face moisturizers, anti-aging creams, primers and some hair serums that need lightweight conditioning without buildup.
Triisotridecyl Trimellitate’s Cosmetic Benefits/Uses
In topical products Triisotridecyl Trimellitate serves mainly one purpose that delivers several user-friendly benefits.
- Skin conditioning: The ester forms a breathable film that softens and smooths the surface of the skin, giving formulas a velvety slip. It helps lock in moisture, improves spreadability and leaves a nonsticky finish, which is especially valuable in lip and face products that need to feel comfortable for hours.
Who Can Use Triisotridecyl Trimellitate
Thanks to its lightweight, nonocclusive nature Triisotridecyl Trimellitate generally agrees with all skin types including oily, combination, normal and dry skin. Sensitive skin users usually tolerate it as well because it lacks common irritants or fragrances, though individual reactions are always possible. Extremely acne-prone skin may prefer to monitor use since richer esters can occasionally contribute to congestion, yet this particular ester is considered low risk in that regard.
The ingredient is synthesized from petroleum-derived feedstocks and contains no animal components or by-products, making it suitable for vegans and vegetarians.
No research suggests problems for pregnant or breastfeeding women when Triisotridecyl Trimellitate is used topically and in typical cosmetic concentrations. Still this is not medical advice, and anyone who is pregnant or nursing should clear any skincare product with their doctor before use just to be safe.
Triisotridecyl Trimellitate is not known to cause photosensitivity, so it will not make skin more reactive to sunlight. It is also fragrance-free and dye-free, reducing the chance of cross-reactions for those with fragrance allergies.
Potential Side Effects/Adverse Reactions
Individual responses to topical Triisotridecyl Trimellitate can vary. The following list outlines potential side effects that are uncommon when the ingredient is properly formulated and used as directed.
- Mild skin irritation
- Allergic contact dermatitis in those already sensitized to similar esters
- Temporary pore congestion or minor breakouts in very acne-prone skin
- Eye stinging or watering if the product accidentally migrates into the eyes
If any adverse reaction occurs stop using the product and seek advice from a healthcare professional.
Comedogenic Rating
Rating: 1 out of 5. Triisotridecyl Trimellitate is a large branched ester that sits on the surface rather than sinking deeply into pores, so its tendency to trap sebum and debris is quite low compared with smaller, straight chain oils. Most lab and consumer reports show minimal clogging even at the higher percentages used in lipsticks and foundations. Still, exceptionally oily or congestion-prone skin could notice a slight uptick in blocked pores if the rest of the formula is already rich. Overall the ingredient is considered suitable for those who break out easily, although individual experiences can differ. Its low comedogenic score also holds up when mixed with silicones or volatile oils, which is how it often appears in modern makeup.
Summary
Triisotridecyl Trimellitate acts mainly as a skin-conditioning lipid that smooths, softens and helps lock in moisture while giving products a silky glide. Its branched structure resists oxidation so it keeps formulas stable and comfortable for long wear. Although not as famous as jojoba oil or dimethicone, it has carved out a steady role in color cosmetics and lightweight creams because it delivers slip without a greasy afterfeel.
Current safety data shows a very low risk of irritation, allergy or pore clogging when used as intended, making it a broadly safe choice for most skin types. As with any new ingredient, trying a small patch first is a smart move to be on the safe side.