I have been on Belviq for 3 weeks and have actually gained 2 pounds. When I started taking it the first couple days had a headache but now no side affects. I have bad hip and back pain so can not really exercise that's one reason the doctor prescribed it for me. It hasn't helped with my appetite at all. Any info would be appreciated I'm 47, female, 5,4" and weigh 212 by my scale.