It is a great conditioning agent for both skin and hair. Guar hydroxypropyltrimonium chloride is especially beneficial as a hair care product. Because it is positively charged, or cationic, it neutralizes the negative charges on hair strands that cause hair to become static or tangled. Better yet, it does this without weighing hair down. With this ingredient, you can have silky, non-static hair that retains its volume and provides a smoother brushing experience.
Guar hydroxypropyltrimonium chloride is generally considered safe. It can cause a mild allergic reaction in the form of irritated skin for some with sensitive skin. This mostly depends on the amount used in the formula...it should not exceed 1.0%. Remember, the farther down the list of ingredients, the smaller the amount. All ingredient list are (should be) listed in order of predominance, with the item with the greatest amount first.