Some new medications in development are also trying to solve for a persistent side effect of existing drugs: Patients who lose fat also tend to lose muscle. This can be particularly dangerous for older adults because it makes them more likely to fall and can worsen osteoporosis.

Novo Nordisk said on Monday it would halt its collaboration with U.S. telehealth company Hims & Hers Health over the distribution of the Danish company's blockbuster Wegovy weight loss drugs. The two companies had announced a collaboration in April for Hims & Hers to sell Wegovy through a bundled offering on the telehealth company's platform.