What to know about Mounjaro, the next game-changing medication awaiting FDA approval to treat weight loss

• Tirzepatide, a medication approved to treat diabetes, helps aid weight loss by lowering appetite.

• A similar drug called semaglutide was approved for obesity and became so popular it caused shortages.

• However, insurance and access for patients in the long-term is uncertain.

Another weight loss medication designed to treat diabetes is part of a promising class of new drugs that may aid weight loss.

Tirzepatide, sold under the brand name Mounjaro,  has attracted attention for dramatic weight loss results, including a clinical trial that found patients lost 20% of their body weight in 16 months while using it.

The study results are a game-changing level of weight loss typically unheard of without weight loss surgery, Dr. Robert Gabbay, chief scientific and medical officer for the American Diabetes Association, told USA Today.

Despite its potential, there are a lot of unknowns about the future of the drug, including access for patients, according to an obesity medicine expert.

Here's how tirzepatide works, how its prescribed, and possible downsides, including side effects, cost, and insurance issues.

It's not yet approved for weight loss, but doctors can prescribe it

One of the most popular existing weight loss drugs, called semaglutide, originated as a diabetes medication, and was FDA-approved to treat obesity in 2021, becoming so popular it caused shortages.

A similar story may unfold with tirzepatide: although it hasn't been approved by the FDA for weight loss, treatment providers anticipate that will change, based on research showing its potential for patients with obesity.

"We do expect that it will be approved for the treatment for obesity," endocrinologist and obesity medicine specialist Dr. Scott Isaacs told Insider, although it's not clear how soon.

In the meantime, patients can still access the drug. The lack of FDA approval for weight loss means manufacturers aren't able to market the drug for weight loss, Isaacs said. Since tirzepatide is already FDA-approved for use with diabetes, doctors are able to prescribe it to patients, even for a different purpose, if they think it will help.

It helps reduce appetite, similar to drugs like semaglutide

Tirzapetide works in the same way as other diabetes medications used to treat obesity, according to Isaacs.

"It's more similar than different to other drugs," he said.