Cheaper, knockoff versions of Ozempic, Wegovy and Zepbound are flooding the market, often promoted by telehealth companies in online ads and by influencers on TikTok and Instagram. These versions of the drugs are made by so-called compounding pharmacies, an obscure corner of America’s pharmaceutical market which makes drugs that aren’t approved by the Food and Drug Administration.

On today’s Big Take podcast, Bloomberg reporters Ike Swetlitz and Madison Muller tell host Sarah Holder about their investigation into a $1 billion shadow industry that could be putting Americans’ health in danger.

Read more: Unsafe Ozempic Knockoffs Are Flooding the Market