(NewsNation) — Pharmaceutical company Novo Nordisk is suing clinics and pharmacies it has accused of selling knockoff versions of Ozempic and Wegovy, drugs in high demand for their effectiveness at weight loss.

Novo Nordisk makes the aforementioned drugs and claims medical spas, wellness clinics and compounding pharmacies are selling cheaper, unauthorized versions of the diabetes and weight loss drugs, the company said in a news release.

“These unlawful marketing and sales practices, including the use of Novo Nordisk trademarks in connection with these practices, have created a high risk of consumer confusion and deception as well as potential safety concerns,” the company said.

The lawsuit comes after FDA warnings about the knockoffs that are cropping up amid a shortage in the official drugs.

NewsNation medical contributor Dr. Dave Montgomery also previously warned about the knockoffs.

“When the FDA says ‘Hey guys, I don’t know what this is that the compounding pharmacies are giving you,’ you probably should back up. I think we should pay attention to them,” Montgomery said Wednesday on “CUOMO.” “Novo Nordisk has done the due diligence — they did the trial that says this is safe, and this is efficacious for what it’s efficacious for.”

Ozempic and Wegovy boomed after going viral on TikTok for helping people lose weight. Ozempic is used to treat diabetes, while Wegovy is an FDA-approved weight loss drug.

Novo Nordisk alleges in its lawsuit that the clinics are selling “compounded” drugs that claim to contain semaglutide, the active ingredient in Ozempic and Wegovy, but are not approved by the FDA.

“Compounded products do not have the same safety, quality and effectiveness assurances as our FDA-approved drugs and may expose patients to health risks,” Novo Nordisk said in the news release. “Novo Nordisk cannot validate the safety or effectiveness of products claiming to contain semaglutide that are not one of our own branded products.”

There’s also been an uptick in emergency room visits among Ozempic users, The New York Post reported. Reported side effects have included diarrhea, nausea and bloating.

When drugmakers start adding other ingredients to the knockoffs, Montgomery says there are other unknown side effects that can pose a danger.

“What about when a compounding pharmacy … puts, say, sodium on the end of it? It sounds benign, but we don’t know what that’s going to do to your physiology,” he said.