It seems like everything has side effects ... I havent gained weight so far and honestly if I did, Id probably stop taking them as much .. Im about 5'8 125 and I dont like to be much heavier than that. maybe I havent taken them long enough to see if id gain weight though .. how long did you take yours for?? I usually take mine first thing in the morning (on an empty stomach) and then I take one before bed but I usually eat at night because I work until 10pm ... so the one at night I always have a full tummy!