Michael Hiltzik: After the FDA delayed enforcement against stem cell clinics, unlicensed operators poured in

In 2017, the Food and Drug Administration closed a loophole exploited by clinics pitching unproven, ineffective and potentially hazardous stem cell therapies directly to consumers.

Those treatments were illegal, the FDA ruled. That was the good news. The agency, however, suspended its enforcement for three years to give these operators time to get right with its regulations. During the pandemic, the FDA added six months to the deadline, so its period of regulatory "forbearance" expired on May 31.

What happened in the meantime? Instead of stem cell purveyors reaching out to the FDA to work out how to meet federal regulations, a torrent of shady operations poured into the field — so many that the task of protecting the public from them may now exceed the FDA's capabilities.

That's the concern of Leigh Turner, a public health expert at UC Irvine, longtime critic