Shares of Hims & Hers Health tumbled 18% premarket on Tuesday as Wall Street analysts questioned the telehealth provider's lofty sales forecast in the face of looming restrictions on compounded weight-loss drugs.

Shares of Hims & Hers Health (HIMS) shares plunged in late trading Monday after the company reported falling margins as costs rose, overshadowing better-than-expected sales. The online healthcare provider’s fourth-quarter revenue nearly doubled year-over-year to $481.

Hims & Hers Health reported fourth-quarter results on Monday that beat analysts' expectations, but the stock sank in extended trading.

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.