What Is Trihydroxystearin?
Trihydroxystearin is a plant-derived fat made by combining glycerin with hydroxystearic acid, a fatty acid usually sourced from castor or other vegetable oils. Chemically it is known as 1,2,3-propanetriyl tris(12-hydroxyoctadecanoate). This tri-ester structure gives it a buttery, wax-like texture that melts on skin.
The ingredient first drew interest in the 1970s when formulators were looking for plant alternatives to mineral waxes. Its ability to thicken oils without feeling greasy quickly put it on the map in skin care. Today it is produced through a simple esterification process: purified vegetable oil is split to release hydroxystearic acid, which is then reacted with food-grade glycerin under heat and vacuum. The finished material is filtered into pale, odorless flakes or beads.
You will spot Trihydroxystearin in rich face creams, eye balms, lipsticks, stick foundations, clay masks and high-performance anti-aging serums. Brands like it because it boosts texture while adding a cushiony feel that consumers associate with luxury.
Trihydroxystearin’s Cosmetic Benefits/Uses
Here is what this multitasker brings to a formula
- Skin Conditioning: forms a soft, occlusive film that slows water loss, leaving skin feeling smooth and comfortably moisturized
- Viscosity Controlling: thickens oils and emulsions so creams stay stable in the jar and glide on without running or separating
Who Can Use Trihydroxystearin
This fatty ester tends to play well with most skin types. Its cushioning, non-greasy finish suits normal, dry, oily and combination skin alike while the soft occlusive film can offer extra comfort for mature or dehydrated skin. The ingredient is rarely a troublemaker for sensitive complexions, though anyone highly prone to pore clogging may want to keep an eye on how their skin responds because it is a richer lipid.
Because Trihydroxystearin is produced from plant oils and glycerin with no animal derivatives, it is considered suitable for both vegetarians and vegans. Manufacturing processes do not normally involve animal testing in regions that have banned the practice, but consumers who avoid animal testing should still check a brand’s cruelty-free status.
Current safety data show no hazards specific to pregnancy or breastfeeding when the ingredient is used in cosmetic concentrations. That said this information is not medical advice and anyone who is pregnant or nursing should run each skincare product past their healthcare provider to be on the safe side.
Trihydroxystearin is not known to increase photosensitivity so there is no special need to avoid daylight after use. As with any skincare ingredient, avoid applying it to broken skin and store products in a cool place so the fats do not oxidize.
Potential Side Effects/Adverse Reactions
Reactions to topical Trihydroxystearin vary from person to person. The effects listed below are potential outcomes only and are highly unlikely to be the typical user experience. When formulated correctly most people will not notice any negative effects.
- Mild pore congestion: its occlusive nature could contribute to clogged pores in very acne-prone skin
- Contact irritation: rare itching or redness can appear in individuals sensitive to fatty alcohol derivatives
- Allergic contact dermatitis: extremely uncommon rash or swelling may occur in those allergic to castor or related plant oils
- Texture changes in makeup: in high amounts it can increase a product’s thickness which may feel heavy on very oily skin
If any irritation, swelling or breakouts occur discontinue use and consult a healthcare professional
Comedogenic Rating
Rating: 2/5. Trihydroxystearin is a waxy fatty ester so it can sit on the surface of skin longer than lightweight oils, which means there is a small chance it may trap debris in very clog-prone pores. Still, its molecular size is larger than typical pore-blocking fats and most formulas use it at low levels, keeping the risk modest.
Most people, even those with combination skin, tolerate it without extra breakouts. Very acne-prone users who react to richer plant butters might prefer to use it sparingly or choose lighter textures.
Comedogenicity can also vary with the full formula: paired with fast-absorbing oils, good emulsifiers and gentle exfoliation, the clogging risk drops further.
Summary
Trihydroxystearin acts mainly as a skin conditioner and viscosity controller. It melts on contact, forming a thin film that slows water loss so skin feels soft and cushioned, and it thickens oils and emulsions, giving creams and sticks a stable, velvety body.
The ingredient enjoys steady but not blockbuster popularity. It features most often in premium balms, lipsticks and rich face creams where a plush finish is key, yet it stays under the radar compared with buzzier actives.
Current safety reviews find it non-toxic, non-sensitising and pregnancy safe at cosmetic levels. As with any new product it is smart to patch test first so you can spot any personal sensitivity before applying to the whole face.