How long does adipex stay in your system to where the side effects will start to decrease thru out the day.

Phentermine: Adipex has a half life of about 24 hours. It takes five half-lives to hit "steady state", and the same time to clear the medication. That means about three days. Many patients develop a tolerance quickly and the side effects - and effectiveness- where's off. On average in about two months. Many people get insomnia and dry mouth taking adipex. Those should where off before tolerance develops