A substance used to prevent a liquid from drying out. Humectants stop water from evaporating and can even attract water molecules from the air.

Lubricants, lotions, and cosmetics often use humectants as a fundamental part of their formulas. Without a proper balance of these substances, a lubricant can quickly take on a tacky or sticky consistency.

Some of the most popular humectants used in lubricants include propylene glycol, glycerin, aloe vera gel, and butylene glycol. These are most common in water-based lubricants; silicone and oil lubes don’t use water and can usually last for a long time without the use of humectants.