What Is Hydrogenated Castor Oil Triisostearate?
Hydrogenated Castor Oil Triisostearate is a plant-derived ingredient made from castor oil that has been fully hydrogenated, then reacted with three units of isostearic acid, a branched fatty acid. The result is a thick, wax-like substance made up of long C18 fatty acid chains bonded in a triple-ester structure.
Castor oil itself has been used in beauty routines since ancient Egypt, but its natural form can feel sticky and break down easily. In the mid-20th century chemists began hydrogenating castor oil to improve its stability. Later they combined the hardened oil with isostearic acid to create Hydrogenated Castor Oil Triisostearate, which offered an even smoother feel and better compatibility with modern cosmetic formulations. Because it stays solid at room temperature yet melts near skin temperature, it became popular in color cosmetics and skincare that need a rich but non-greasy texture.
The ingredient is produced in two main steps. First, raw castor oil is exposed to hydrogen gas under heat and pressure, saturating its double bonds and making it more stable. Second, the hydrogenated oil reacts with isostearic acid in the presence of a catalyst to form the triester. After purification it appears as an off-white, odorless wax ready for cosmetic use.
You will most often see Hydrogenated Castor Oil Triisostearate in lipsticks, lip balms, cream blushes, foundations, moisturizers, solid cleansing balms, sunscreen sticks and intensive overnight masks where it helps give a smooth glide and long-lasting comfort.
Hydrogenated Castor Oil Triisostearate’s Cosmetic Benefits/Uses
Formulators rely on this ingredient for two main reasons:
- Skin conditioning – It forms a soft, flexible film on the skin or lips that traps moisture and leaves the surface feeling supple and nourished. This helps prevent dryness, improves the look of flaky areas and boosts overall comfort in both skincare and makeup products.
- Viscosity controlling – Being a solid wax at room temperature, it thickens oils and emulsions, giving creams, balms and color products the right body so they hold their shape in the jar yet spread easily on contact with skin.
Who Can Use Hydrogenated Castor Oil Triisostearate
This waxy emollient suits most skin types, especially normal, dry and combination skin that crave extra softness and moisture retention. Sensitive skin usually tolerates it well because it contains no fragrance or common irritants. Very oily or acne-prone skin may find the rich film too occlusive, so those users often prefer lighter alternatives.
Because the raw material comes from castor beans and plant-derived fatty acids, it is appropriate for vegans and vegetarians. No animal derivatives or animal testing are involved in its standard production.
The ingredient is considered low risk for women who are pregnant or breastfeeding since it stays on the surface of the skin and has a long history of safe topical use. This is not medical advice and anyone who is expecting or nursing should still confirm with a healthcare professional before starting a new product.
Hydrogenated Castor Oil Triisostearate does not increase photosensitivity, so it will not make skin more prone to sunburn. It is also odorless and free of known endocrine disruptors, making it a straightforward choice for formulas that aim for a clean label.
Potential Side Effects/Adverse Reactions
Reactions to topical Hydrogenated Castor Oil Triisostearate differ from person to person. The following list covers potential side effects that could occur, but most users will not experience them when the ingredient is properly formulated and used as intended.
- Clogged pores and breakouts – its waxy nature can occasionally trap sebum and debris, leading to comedones in very oily or acne-prone skin
- Mild skin irritation – a small number of individuals may notice redness, itching or a stinging sensation due to personal sensitivity
- Contact allergy – rare cases of allergic dermatitis have been documented with castor derivatives, often presenting as localized rash or swelling
- Heavy or greasy after-feel – some users may find the finish too rich, especially in hot humid climates
If any discomfort, persistent redness or other unwanted reaction occurs stop using the product and seek guidance from a qualified healthcare professional.
Comedogenic Rating
Hydrogenated Castor Oil Triisostearate carries a comedogenic rating of 2 on the 0-5 scale. Its large, branched fatty acid structure can sit on the surface and slow water loss, but that same film may trap oil and dead cells if your skin already produces excess sebum. The molecule is less pore-blocking than pure waxes or thicker butters, yet richer than light esters or silicones, placing it in the low-to-moderate range.
People who often break out might prefer lighter emollients, while those with normal or dry skin usually have no issues. Formulation matters too: when blended with volatile oils or breathable textures its clogging potential falls even lower.
Summary
Hydrogenated Castor Oil Triisostearate conditions skin by forming a soft flexible layer that locks in moisture and smooths rough patches. Its solid-at-room-temperature nature also thickens creams, balms and sticks so they feel plush yet glide easily. These dual talents explain why it shows up in lipsticks, cleansing balms, tinted moisturizers and other products that need structure plus comfort.
While not as famous as shea butter or coconut oil, it enjoys steady popularity with formulators who want a plant-based wax that melts at body temperature and stays stable over time. Safety reviews and decades of topical use point to a low risk of irritation or systemic effects, but skin is personal so it is smart to patch test any new product that contains it.