Trihydroxystearin
2,3,4-Trihydroxyoctadecanoic acid
I. Basic Information
Trihydroxystearin (CAS No. 139-44-6, EC No. 205-364-6) is a triglyceride compound formed by esterifying glycerol with three molecules of 12-hydroxystearic acid, with the molecular formula C₅₇H₁₁₀O₉ and molecular weight 939.48 g/mol. It is also commercially known by synonyms such as glyceryl tris-12-hydroxystearate, castor wax, and Ambrosol THS (Ultra) .
Naturally occurring in trace amounts as an oxidation product of stearic acid-containing lipids, it is primarily produced synthetically for industrial applications. Classified as a non-ionic wax-like substance, it exhibits excellent biocompatibility and is generally recognized as safe for use in cosmetics, pharmaceuticals, and food-related products ^.
II. Physical & Chemical Properties
At room temperature, trihydroxystearin appears as a white to off-white odorless waxy solid with a melting point range of 85–88°C . It is insoluble in water but soluble in mineral oils, vegetable oils, silicones, and low-polarity aliphatic solvents .
Key properties include:
Thixotropic thickening: Exhibits shear-thinning behavior, reducing viscosity under shear and restoring it at rest .
Hydrogen bonding capability: Multiple hydroxyl groups enable hydrogen bond formation, contributing to its hygroscopic nature and emulsifying stability ^.
Low reactivity: Chemically stable under normal conditions, compatible with most cosmetic and pharmaceutical ingredients .
III. Production Methods
The primary industrial production route involves catalytic hydrogenation of castor oil, which converts ricinoleic acid (the main fatty acid in castor oil) to 12-hydroxystearic acid. This is followed by esterification with glycerol under controlled temperature and pressure to form the triglyceride structure ^.
Alternative methods include direct hydroxylation of stearic acid followed by condensation with glycerol, but these are less common due to lower efficiency and higher production costs ^. The final product is typically refined into a fine powder or flake form for ease of formulation ^.
IV. Applications
Trihydroxystearin's unique combination of thickening, emulsifying, and film-forming properties makes it versatile across multiple industries:
Cosmetics & Personal Care: Used as a rheology modifier, emollient, and stabilizer in skin care products (moisturizers, serums), makeup (foundations, lipsticks, pressed powders), and stick formulations (deodorants, crayons) ^. It enhances product spreadability, improves water retention by forming a skin barrier, and prevents phase separation in emulsions .
Pharmaceuticals: Serves as an excipient in sustained-release oral capsules and topical ointments, controlling drug release rates and improving formulation stability .
Industrial Coatings: Acts as a thixotropic agent in paints, inks, and adhesives, preventing pigment settling and improving application properties .
Food Additives: Used in limited quantities as a formulation aid and release agent, though its primary applications remain in cosmetics and pharmaceuticals .
V. Application Cases
Cosmetics: Long-Lasting Lipstick Formulation
A leading beauty brand incorporated 3–5% trihydroxystearin into its matte lipstick line to improve texture and longevity. The compound thickened the oil phase, enhanced pigment dispersion, and formed a water-resistant film on lips, extending wear time by 40% while maintaining a non-drying feel .Pharmaceuticals: Sustained-Release Capsules
A pharmaceutical manufacturer used trihydroxystearin as a matrix material for extended-release pain medication. Its thixotropic properties allowed for controlled drug release over 12 hours, reducing dosing frequency and improving patient compliance .Industrial: High-Performance Printing Inks
An ink manufacturer added 2% trihydroxystearin to offset printing inks to prevent pigment settling during storage. The thixotropic structure ensured consistent ink flow during printing, reducing streaking and improving print quality on non-porous surfaces .
Shanghai Better Chemical Co., Ltd. was established in 2005, specializing in fatty alcohols, fatty acids, glycerin, white oil, and petroleum jelly. These products serve a wide range of industries, including personal care, flavor & fragrance, textiles, plastics, food, pharmaceuticals, stationery, construction, and coatings. With 21 years of professional experience, the company has earned consistent recognition across the industry and established partnerships with over 4,000 clients. It maintains a skilled technical team, efficient warehouse operations, high-quality pre- and after-sales services, and lightning-fast logistics. We look forward to collaborating with you. For inquiries, please call: +86 21 5102 9963.