Napster forever changed the music industry even though its business model was ultimately deemed illegal. Could a similar change be sweeping through America’s drug market?

The Trump administration this month took a hard-line stance against telehealth company Hims & Hers Health, with its health agency referring the telehealth firm to the Justice Department for potential federal violations. The rampant compounding of GLP-1 drugs—where pharmacies essentially sell knockoffs of the same active ingredients—isn’t going away quickly, but doing it on a massive scale now feels far more precarious. Novo Nordisk is suing Hims & Hers, alleging violations of the patents covering Ozempic and Wegovy.

Wall Street is taking notice: Hims & Hers shares have fallen nearly 30% since the Trump administration’s move. The bigger question now is how the market will evolve and what ripple effects this shift will have beyond GLP-1s.

The music industry offers a useful parallel. For decades, record labels reigned despite the occasional bootleg tape. Then Napster arrived with online file sharing. Suddenly, it felt as though all the world’s music was permanently free to anyone with an internet connection.

That model didn’t last. Lawsuits eventually drove Napster into bankruptcy, and the era of totally free music came to an end. But the genie was out of the bottle. Once consumers experienced instant, frictionless access to music, there was no going back. The result was a new generation of applications—first iTunes, then Spotify—where the content was paid for but the convenience remained.

Pharma now faces a similar transformation. An aggressive FDA crackdown may finally rein in mass GLP-1 compounding, but history suggests this is only a bridge to a different kind of disruption.

Drug companies sell most of their medicines through a web of middlemen—wholesalers, pharmacy-benefit managers, and insurers—that use inflated list prices and rebate schemes. The system is so opaque that even employers and the government struggle to see how prices are actually set. Over time, these middlemen have built vertically integrated structures designed to extract value from America’s uniquely convoluted drug-distribution model.

That system is being challenged, and the direct-to-consumer model for weight-loss drugs offers a glimpse of what could come next. GLP-1s are a special case: Patients are willing to pay cash and bypass insurance altogether. But the broader movement toward price transparency and patient empowerment is accelerating in different corners of healthcare. Examples include Mark Cuban’s Cost Plus Drugs, which offers drug prices at a transparent low price, and Thatch, which helps employees navigate insurance to choose better plans. Together, these sort of startups shift power back to consumers.

The Hims & Hers strategy of undercutting patented drugs arguably went too far and always seemed like a mirage, as far as strategy goes. Mass compounding was allowed only because of a drug shortage that was bound to be resolved—as it was last year. “We’re told this isn’t really mass compounding,” says Mike Doustdar, chief executive of Novo Nordisk, in an interview this past week. “I say: You have a Super Bowl ad; this is crazy. At some point, they have to ask themselves: Do they want to be Napster or Spotify?”

Ro, a competitor to Hims, points to a different path. Rather than leaning on legally murky, high-margin compounded drugs, Ro acts as a telehealth gateway for branded medications. Ro also sold compounded GLP-1s during the shortages, but both Eli Lilly and Novo Nordisk now sell their drugs on the platform. As CEO Zach Reitano explains: “Too many problems in our healthcare system exist because the patient does not control the flow of money at the point of purchase,” he says. “When they do, the system rewires itself.”

For now, much of this change is still confined to GLP-1s, not the drugs most people buy with insurance. Even TrumpRx, an online drug portal launched just as regulators were cracking down on Hims & Hers, offers only a narrow set of medications at prices few people can realistically pay in cash. The bulk of the system still flows through large drug distributors and dominant pharmacy-benefit managers.

But that system is under pressure. Just this month, two major policy changes, long in the making, happened rather quietly: The Federal Trade Commission attempted to dismantle key pillars of the PBM rebate model in a recent settlement with Cigna’s Express Scripts, while Congress enacted legislation, as part of the recent government funding bill, that should reduce the relationship between drug prices and what PBMs earn. PBMs have long feared these moves and have thus been changing the way patients pay for drugs. The FTC settlement even forces Express Scripts to give members access to TrumpRx pricing.

Much more disruption is yet to come to healthcare, both from governments and businesses. As Reitano puts it, GLP-1s reveal what happens when the patient is also the customer.

Imagine if the rest of healthcare had to operate under the same rules.

Write to David Wainer at david.wainer@wsj.com