You can sleep with eyelash serum on. Generally, as long as you wait a few minutes before heading to bed, your serum should stay on your lashes and be okay through the night.
With that said, we recommend using an all-natural or gentle serum on your eyes before bed to avoid irritation.
Serum, in particular, is great before bed because it can be thick and bother your eyes if they are open. Of course, if you prefer not to sleep with serum on, you can always wipe it off before going to bed.
Eyelash serums are essentially growth-enhancing formulas that help promote thicker, healthier lashes. Using lash serum consistently will extend your eyelash's telogen growth phase, which is responsible for how thick and long your eyelashes grow.