After shampooing, squeeze out excess water so the mask can adhere to the hair fibre rather than slide off. Distribute a generous amount through damp lengths and ends, then wait three to five minutes before rinsing thoroughly with lukewarm water. For hair that is very dry, thick, coloured, or frequently heat-styled, leaving the mask on for up to ten minutes allows the aloe polysaccharides and ceramides more time to form a hydrating film and reinforce the cuticle layer.
There is no advantage to leaving it on for 20 or 30 minutes; the active ingredients have already saturated the hair surface by that point, and prolonged contact can make rinsing harder or leave a slight residue on finer textures. If you accidentally leave it on longer, simply rinse well — no harm done, but no extra benefit either.