"been taking for 4 years 1/2 tablet 12.5 mg. &gt;20 years fell asleep them wake up stay up.  now sleep almost every night all night. no side effects noticed. drowsy if take whole tablet but good on half. i freak if i forget them on holidays cause i know i won&#039;t sleep. no better or worse than before i started taking them but i just love my sleep and hate not sleeping. so thumbs up. i take no other meds or drugs."