Yes, it does appear that Dupixent can cause weight gain, although this is not listed as a side effect in the product information. A case series of 12 people prescribed Dupixent reported an average weight gain of 6.1kg over one year – the amount of weight gained ranged from 0.1kg to 18.0kg. Anecdotally, blog sites also report weight gain as a side effect. How Dupixent causes weight gain is not known; however, people should be informed that weight gain may be a possible side effect of Dupixent.