No not at all. Vitamin supplement don’t cause weight gain. The only side effects can happen if you’re allergic to some of their content which is probably very rare.
Some vitamins aren’t enteric coated and can cause nausea and vomitting but most don’t if taken on a full stomach , right after a meal. Centrum, epivite, perfectil, revitale multi, surbex Z are the ones I have tried and they never cause any nausea or anything like that.