What would happen if i took sleep aid while on lexapro (escitalopram)?

Depends which one: some sleep aids are safe with Lexapro (escitalopram) ,for your age , your physical health , some are not that safe . There are no major drug- drug interaction between Lexapro (escitalopram) and commonly used sleep aids , but its the side effect profile of sleep aid that matters .

Most sleep aids: would be ok. But if you tell us the specific sleep aid you had in mind then we can provide you with a definitive answer rather than a guess.