Does xanax cause weight gain. . Does Xanax Cause Weight Gain - Health Knowledge Made . Have a Health question? Get an answer from a verified Doctor or Nurse online. . Everything you need to know about does xanax cause weight gain, including common uses, side effects, interactions and risks. No, xanax does not cause weight gain. . . . However, it can make some people quite lethargic in the short term, and a lack . . . . If anything it makes you feel more relaxed. . . . NotThere are many possibl... more