Although weight gain is not listed as a side effect of Benlysta in the product information, a phase IV clinical study that analyzed side effect information from 14,100 people who had taken Benlysta reported weight gain as a side effect for 2.87% of them (404 people).
Weight gain is more likely in females aged 50 to 59 years who have been taking Benlysta for 1 - 6 months.
Weight gain can also be a side effect of other conditions, such as depression, and if you experience changes in your weight, you should talk with your doctor