Hydroxypropyl Guar

Hydroxypropyl guar is a cellulose-like polysaccharide derivative used mainly as a thickener/film-former in low concentrations (typically <1%) and is generally well tolerated, including in sensitive-skin formulations. Human repeat-insult patch testing and post-market experience suggest a very low rate of irritation or sensitization, with occasional reactivity usually tied to overall formula factors rather than the polymer itself. Because rare irritation can still occur in highly reactive or eczematous skin—especially under occlusion—I score it as very gentle rather than completely inert. Safety Notes: In commercial skincare, hydroxypropyl guar is most often used as a rheology modifier/film former at low levels (~0.05–0.3%) in lotions, cleansers, and micellar/gel textures where it provides slip and mild thickening. Higher levels are seen in consumer-available high-viscosity gels, barrier/anti-chafe balms, and peel-off/film-forming mask-type products, where total polymer load can push hydroxypropyl guar to ~0.8–1.5% before texture becomes overly stringy/tacky and processing becomes difficult. Rinse-off products typically sit toward the low-to-mid end for ease of spread and rinsability, while leave-on gels and masks more commonly reach the upper end for structure and film formation.