"started taking phentermine 9-26-14, i weighed 196lbs. had my first weigh in today 10-9-14, i now weigh 187lbs. i lost 9 lbs in 2 weeks. side effects i&#039;m having are dry mouth, headaches and stomach pains, but that could be my loss of appetite throughout the day and not eating. and insomnia. i was taking the pill at 10am. i am now switching to half a pill and at 8am. will see if it works better for me."