Everything to Know About the New Weight-Loss Drug

• The FDA is expected to approve tirzepatide for weight loss this year.
• Clinical trials found patients lost an average of 22.5% of their body weight on the drug.
• The drug is not expected to be affordable for most.

A drug currently approved to improve blood sugar regulation in adults with type 2 diabetes is expected to be approved by the Food and Drug Administration (FDA) for weight loss this year—and there are plenty of concerns about who will be able to afford it.

The drug, which is called tirzepatide (or its brand name of Monjaro), could lead to up to $48 billion in annual sales and may become the most popular drug ever once it’s approved, experts tell NBC News.

Its use is expected to expand to include weight loss treatment thanks to impressive findings in a phase 3 clinical trial. In the trial, researchers found that patients lost an average of 22.5% of their body weight (or about 52 pounds). By comparison, similar weight loss drugs Wegovy and Saxenda reduced body weight by around 15% (Wegovy) and 5% (Saxenda).

But what is tirzepatide, exactly, and how does it work? Here’s what you need to know.

What is tirzepatide?

Tirzepatide is in a class of medications called GLP-1 agonists, which mimic hormones that are involved in blood sugar control and appetite. It’s taken via injection once a week and has been shown to decrease how much food people eat and increase how much energy they burn, according to a press release from drug maker Eli Lilly.

There are other GLP-1 agonists on the market—Wegovy and Saxenda—but tirzepatide has an element that mimics a hormone called GIP which can reduce appetite and improve how well your body breaks down sugar and fat, Eli Lilly explains. The elements of the drug “work together to improve how the brain sees weight, which leads to weight loss and better blood sugar regulation” says Fatima Cody Stanford, M.D., Ph.D., an obesity medicine physician and clinical researcher at Massachusetts General Hospital.

In phase 3 clinical trials, patients lost an average of 15 more pounds with tirzepatide than with a placebo and an average of 23 pounds more than the placebo group when they used tirzepatide and insulin.

“Currently the GLP-1 agonists are very popular for weight loss,” says Jamie Alan, Ph.D., associate professor of pharmacology and toxicology at Michigan State University. “It is anticipated that this drug is going to be much more beneficial.”

“This is another tool to help with weight loss,” says Mir Ali, M.D., bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, Calif. “But if it’s not used properly—with lifestyle modifications—it will eventually not work.”

What is tirzepatide used for?

Tirzepatide is currently approved by the FDA to help improve blood sugar regulation in adults with type 2 diabetes as an addition to diet and exercise (as of May 2022). The medication specifically helps control blood sugar and is also injected under the skin once a week. The dose is adjusted as people meet their blood sugar goals, the FDA explains.

What does tirzepatide cost?

As of right now, GoodRx says that tirzepatide costs in the mid-$900 to about $1,200 range for four pens without health insurance. However, the cost of the drug “is going to vary depending on insurance,” Alan says.

Stephanie Field, director of pharmacy operations at Corewell Health West, says that patients with type 2 diabetes who qualify for co-pay assistance through Eli Lilly can pay as little as $25 a month. However, that’s for patients who are taking the drug for diabetes—not weight loss.

Is it covered by insurance?

Right now, the drug “is only covered for patients with type 2 diabetes,” Field says, noting that “utilization for weight loss is considered off-label and not covered by a patient’s insurance.” (However, that may change once the drug receives FDA approval for weight loss.)

Once tirzepatide is FDA approved, Dr. Ali says it’s “not likely” to be approved by most insurance companies. “If it is, it will be quite expensive for most patients,” he says. “Hopefully, that will change with time.”

Field says patients can expect the cost of tirzepatide for weight loss to be similar to that of other similar medications on the market. “There are two GLP-1 medications with weight loss indications approved by the FDA—Saxenda and Wegovy,” Field says. “Cash prices for patients can vary depending on the pharmacy, but averages around $1,000 for a month of medication.”

However, if you have a high level of insurance coverage, Dr. Stanford says the drug may be more affordable. “If not, this would be cost prohibitive,” she adds.

Who can afford tirzepatide?

It depends. “It depends on your insurance. It also depends on your own personal finances and how important this medication is for you,” Alan says. Once the drug is approved by the FDA, “some insurances might cover it for diabetes or pre-diabetes and not cover it for weight loss,” Alan says.

How safe is tirzepatide for weight loss?

In general, the drug is “fairly safe,” Alan says. However, she adds, “we will know more as more people take this drug.” Currently, the FDA lists the following as potential side effects of tirzepatide:

• nausea
• vomiting
• diarrhea
• decreased appetite
• constipation
• upper abdominal discomfort
• abdominal pain

Nausea is a common side effect, Alan points out, but tirzepatide is still generally is considered a safe option. “Always talk to your doctor to see whether this drug is safe for you,” Alan says.