Stearoxy Hydroxypropyl Methylcellulose — INCI reference

What it is

Stearoxy Hydroxypropyl Methylcellulose is the reaction product of stearyl glycidyl ether and hydroxypropyl methylcellulose (HPMC), a cellulose derivative. C18 stearyloxy groups are grafted onto the HPMC backbone via hydroxypropoxy linkages, introducing hydrophobic character to an otherwise hydrophilic polymer. This modification enables effective thickening at low concentrations (typically 0.1–1.0% by weight), producing stable, thixotropic gels. Formulations remain water-soluble when stearyloxy content is kept at or below approximately 0.6% by weight; higher loadings require water–alcohol co-solvents. The ingredient maintains consistent viscosity across a broad pH range, making it compatible with vitamin C derivatives and many active ingredients. It is used in foundations, serums, moisturisers, sun-care products, and eye-area formulations. Its film-forming properties also contribute to long-wear and transfer-resistance in decorative cosmetics.

Safety & warnings

No specific allergen, irritant, or comedogenic concerns are documented in major regulatory databases. EWG Skin Deep lists the ingredient but no significant hazard data are on file. As a cellulose ether, it is structurally related to hydroxypropyl methylcellulose (HPMC), which has a well-established cosmetic and pharmaceutical safety record. Standard patch-test caution applies for individuals with known sensitivities to cellulose-derived excipients.

Origin & sourcing

Synthesised by reacting stearyl glycidyl ether with hydroxypropyl methylcellulose (itself derived from wood-pulp or cotton-linter cellulose). The etherification reaction introduces C18 stearyloxy groups, yielding a semi-synthetic, cellulose-based polymer. No animal-derived starting materials are required; the cellulose backbone is plant-sourced.

History

Developed and commercialised by Daido Chemical Corporation (Japan) under the trade name Sangelose. The ingredient is listed in the EU CosIng database with the function of viscosity controlling agent. It has been cited in multiple international patents (US 9,119,785; US 9,855,199; US 11,660,262) covering cosmetic base compositions that exploit its thickening and film-forming properties.

Questions everyone asks

What does Stearoxy Hydroxypropyl Methylcellulose do in a skincare product?

It acts primarily as a viscosity-controlling agent, thickening formulations into stable gels or creams. At low use levels it can also contribute to film formation on skin.

Is Stearoxy Hydroxypropyl Methylcellulose natural or synthetic?

It is semi-synthetic. The cellulose backbone comes from plant sources (wood pulp or cotton), but the stearyloxy groups are introduced through a chemical etherification reaction, making the final ingredient a modified, synthetic derivative.

What brand makes this ingredient commercially?

It is sold under the trade name Sangelose by Daido Chemical Corporation in Japan, in several grades (e.g., Sangelose 90L, 90M, 90H) that differ in viscosity and stearyloxy content.

Is there safety data available for this ingredient?

Dedicated published safety studies are limited. It is registered in the EU CosIng database as a permitted cosmetic ingredient, and its parent polymer HPMC has extensive safety documentation in both cosmetic and pharmaceutical contexts.