Hydroxypropyl guar is a natural thickener, usually appearing as a white powder, derived from guar gum. Guar (Cyamopsis tetragonoloba) is a domesticated legume crop, with most of of the world's production in India. Cultivated plants grow to around 1 meter tall, with hairy stems and leaves. The leaves, seed pods and seeds are all known to be edible, and are often cooked in curries. Harvested seeds or 'guar beans' are dehusked, roasted, hydrated and ground to produce guar gum.

Guar gum is composed of sugars that make it a cold-soluble thickening agent. It is used to thicken many foods and personal care products, and is a cheaper plant-derived alternative to locust bean gum, which requires greater amounts to achieve the same level of viscosity.

Hydroxypropyl guar is produced by reacting propylene glycol with guar gum, which improves its solubility and stability.

Other names: Guar Gum, 2-Hydroxypropyl Ether, Hydroxypropyl Guar Gum