Glycerin is a humectant that is used in moisturisers. It is water-binding and capable of drawing and retaining water from the air, aiding the skin in maintaining moisture. Glycerin's hydrating properties have been very well researched and Glycerin is a superb skin-moisturising agent. Glycerin also increases the spreadability of creams and lotions.

Can products with glycerin removes water from the skin when used in a dry atmosphere?  This will happen only with pure glycerin (100% concentration). Cosmetic products generally use glycerin at 5% or lower.  Any humectants (including glycerin) used in their pure form will result in water loss by drawing water from the lower layers of the skin into the surface.