Action News Investigation: Testing online weight loss medications for potency | Here's what we found

PHILADELPHIA (WPVI) -- New weight loss drugs, like Wegovy and Zepbound, are surging in popularity. So is the desire to buy the drugs online or on the less regulated secondary market.

The Action News Investigative Team and ABC News collaborated to buy drugs online and test them for potency and ingredients.

Some of the purchased drugs have the key weight loss drugs semaglutide and tirzepatide, but are mixed with other ingredients.

We bought them from three different sites, purchasing 11 samples in total.

The first said the items listed on their site are for "research purposes only."

The second site asked a few questions about medical history but did not require a prescription.

The third website asked for a more detailed medical history, a photo ID and a full body photo. After submitting their information, our producers received a message saying a doctor had approved a prescription for the medication despite never speaking to a medical professional.

We eventually acquired 11 samples to be sent out and tested by a lab to see how much of the active ingredient each contained.

Lab results show six had between 90% and 110% of the listed active ingredient -- a range the lab said is accepted as an industry standard.

One sample had none of the active ingredients listed on the label.

"Unfortunately, differences in the actual potency of medications and what is advertised on the internet is not uncommon, and it doesn't surprise me at all," said Dr. Charlie Seltzer, a weight loss and lifestyle specialist.

Dr. Seltzer said people go to the internet for these weight loss drugs because they are cheaper and easier to acquire, especially when someone's insurance won't cover the cost.

"And the reputable ones, yes, are safe," he said. "The problem is, you don't know if they're reputable or not, and they're popping up on the internet every five minutes and it's like the Wild West."

In our testing, one site's medication was extremely inconsistent. Two of the vials had less than 90% of the listed active ingredients, while two others had more than 250% of the listed potency, which could lead to overdose symptoms like fainting, nausea and pancreatitis.

We shared the results with all three companies. One declined to comment and the other two haven't responded.