Eli Lilly, the pharmaceutical company that makes the weight loss drug Zepbound, announced in a press release last week that it has begun offering single-dose vials of the medication at a fraction of the cost of its preloaded injector pens. 

The new single-dose vials are the “same medication but packaged in vials rather than in preloaded pens for ease of injection,” Ilana Ramer Bass, MD, assistant professor of endocrinology, diabetes, and metabolism and head of the weight loss program at Mount Sinai Morningside, told Health. “With the vials, the patient will need to draw up the medication with a separate syringe and inject with a needle.”

Zepbound, a brand-name version of tirzepatide, is part of a class of medications called glucagon-like peptide 1 (GLP-1) agonists. It was approved by the Food and Drug Administration for weight management in 2023.

Since then, demand has soared, leading to drug shortages and reliance on compounded versions, which the FDA has linked with overdoses due to dosage errors (the products also include vials and syringes rather than preloaded injector pens).

“These new vials not only help us meet the high demand for our obesity medicine, but also broaden access for patients seeking a safe and effective treatment option,” said Patrik Jonsson, president of Lilly Cardiometabolic Health and Lilly USA.

Here’s what you need to know about who might benefit from the new medication, how much it costs, and whether experts are concerned that it could also lead to dosing errors.

Like Zepbound preloaded injector pens, the new vials will be available by prescription. 

“The new form of Zepbound will be available to those medically qualified,” Matthew Freeby, MD, director of the Gonda Diabetes Center at UCLA, told Health. “Indications include people with obesity and a body mass index of 30 or higher.”

People who are overweight—classified as having a BMI of 27 or higher—and also have a weight-related health condition, such as heart disease, hypertension, high cholesterol, type 2 diabetes, and obstructive sleep apnea—will also qualify for the vials, Freeby said.

According to Eli Lilly, a four-week supply of the Zepbound vials that provide 2.5 milligrams (mg) doses of the medication will cost $399, or $99.75 a vial. A four-week supply of the vials that provide 5-mg doses of the medication will cost $549, or $137.25 a vial. This is “less than half the list price” of similar weight loss drugs, the press release said.

The new Lilly drug is cheaper than injector pens due to how it’s made, Bass said. “It’s less labor intensive and requires less materials to package the solution in a vial—and to sell syringes and needles separately,” she said. That allows “the pharmaceutical company to charge less and to produce more of the medication.”

Eli Lilly will sell the new drug through its telehealth platform, LillyDirect.

The medication may be especially beneficial for people who need to pay for weight loss drugs out of pocket. Lilly’s new drug “can be really great for people who have obesity, but their insurance plan does not cover medications for weight loss,” Bass said.

However, the drug is only offered at a maximum of 5 mg, which may lead some people to eventually have to pay for the higher dosage, higher cost option.

“There is concern that this might be a way to get more patients on Zepbound at the lowest doses and then increase the chances that they will pay out-of-pocket for the higher doses once they start on the weight loss journey and see some success,” Bass said.

Patients typically titrate upwards on their Zepbound dosage every four weeks by 2.5-mg increments and go up to 15 mg weekly, as tolerated, Bass explained. “So, if a patient reaches a plateau and is not losing further weight at the 5-milligram dose, they might consider paying full price for the pen injector forms of Zepbound.”

However, many people have achieved substantial weight loss even when taking 5 mg: “In prior studies, people with obesity lost an average of 15% of body weight with the five-milligram weekly dosing,” Freeby said.

Like compounded weight management drugs, Lilly’s drug will also require people to use a syringe to draw out medicine. While Bass acknowledged that a patient “theoretically could draw up too much of the medication and administer the incorrect dose,” Freeby said he doesn’t think it’s likely to be a significant problem.

“Lilly’s new product alleviates many of the fears we convey to patients receiving compounded medications,” Freeby said. “The vials Lilly will provide are a known product from a known company and safe for delivery.”

A spokesperson for Eli Lilly told Health that “LillyDirect’s self-pay channel will facilitate access to important patient tools, like training and instructional materials to help patients understand this new option and correctly administer the medicine via needle and syringe. The FDA-approved label for Zepbound also includes detailed instruction for using Zepbound single-use vials.”

“We recommend patients talk to their health care provider about dosage needs to make a treatment decision that is right for them,” the spokesperson added.