Gel

Gels thicken water rather than oil. Gelling agents such as carbomer or xanthan gum give the formula body without adding grease. It slips on, cools as the water evaporates and leaves almost nothing you can feel within a minute. Humectants do the hydrating: glycerin, hyaluronic acid and panthenol pull water into the top layer of skin and hold it there.

Setting speed is what makes gel liners and brow gels hold their line. Film formers in the base dry into a flexible skin that resists smudging far better than a cream does. This matters on an oily lid where cream liner migrates into the crease within hours. That same speed cuts your blending window to seconds, so place the product first and soften it immediately.

Nothing in a gel holds water in for long, and that is the catch. What goes on can leave again. A gel alone on dry skin often feels tight within the hour. It needs a cream or a facial oil over it to seal. Read the ingredient list for denatured alcohol near the top: it speeds drying and delivers that clean finish, and it stings on cracked, freshly exfoliated or shaved skin. Gel-cream hybrids exist for exactly this gap, adding a small oil phase while keeping the light feel.