Hims & Hers on Monday released fourth-quarter results that disappointed on gross margin and sparked concerns about the future of its weight loss business.

Hims & Hers said on Monday that it may no longer be able to sell compounded versions of the weight-loss drug made by Novo Nordisk because its pathway to do so closed when the U.S. FDA declared Friday that the drug's shortage was over.

Investors are scrambling to adjust, after the telehealth specialist Hims & Hers said it would stop selling an alternative to Novo Nordisk's Wegovy and Ozempic weight-loss drugs. Hims stock stood about 17% lower at under $42.