Weight loss drugs including Zepbound, Wegovy in shortage, FDA says

The newest weight loss drug on the market is facing a shortage of supply, according to the U.S. Food and Drug Administration.

Some dosages of Zepbound are in limited supply through the end of April due to what the FDA describes on its website as "demand increase."

Currently, the 5 mg and 12.5 mg doses of the drug have "limited availability."

The FDA approved Zepbound in November as a weight loss management treatment for people with obesity, or those who are overweight with at least one related underlying condition, such as high blood pressure.

As a diabetes drug, Zepbound is sold under the brand name Mounjaro, as the two medications contain the same active ingredient, tirzepatide.

Mounjaro is approved by the FDA to treat Type 2 diabetes but some doctors prescribe the medication "off-label" for weight loss, as is permissible by the FDA. It also has limited availability in several doses through April, according to the FDA's website, which also cites "demand increase" as the reason for the shortage.

Both Mounjaro and Zepbound are manufactured by the Eli Lilly Co., which told ABC News in a statement Thursday it is working to boost supply of the drugs amid an "unparalleled surge in demand."

"We recognize this situation may cause a disruption in peoples’ treatment regimens and are working with purpose and urgency to address it. As a medicine company, we know that people rely on us to help reach and maintain their health goals, and we take our responsibility very seriously," a Lilly spokesperson said in a statement. "While we anticipate intermittent availability in the near term due to unprecedented demand, we expect our investments in manufacturing and supply capacity to progressively increase production of Mounjaro and Zepbound throughout the second half of 2024. You can find updates on the supply status of these medicines on the FDA Drug Shortages Database.

the spokesperson continued, "Given local and regional supply chain dynamics, patients having trouble obtaining their medicine at one pharmacy may try revisiting their pharmacy at a later time or exploring other pharmacies in their area. Alternatively, if someone continues to experience difficulty obtaining their medicine, they can contact their healthcare provider who can assist with their treatment plan."

David Ricks, the CEO of Eli Lilly, told Bloomberg in August that the shortages stem from the complexities of making the medications' pre-filled injectable pens, describing it to the business outlet as "some of the most complex” production systems “on the planet," according to Bloomberg.

Another popular medication for weight loss, Wegovy, also has limited availability in several dosages due to "demand increase," according to the FDA.

Wegovy, like Zepbound, is FDA-approved for weight loss. Its main ingredient is semaglutide, which is also found in Ozempic, a medication that is approved by the FDA to treat Type 2 diabetes but is also prescribed "off label" for weight loss.

Ozempic, which, like Wegovy, is manufactured by Novo Nordisk, is currently available in all dosages, according to the FDA.

A company spokeswoman told ABC News in a statement it is working to "more than double" the amount of lower doses of Wegovy available to patients in the United States.

"Novo Nordisk has made significant investments and has been steadily increasing capacity to produce more Wegovy than ever before. Since January 2024, we are enabling more new U.S. patients to initiate treatment by more than doubling the amount of the lower dose strengths of Wegovy into the U.S. market, while gradually increasing overall supply throughout the rest of the year," the spokeswoman said. "We will closely monitor market dynamics and prescribing trends and will continue to manage shipments as best as possible in an effort to support continuity of care for patients. However, it’s important to be aware that overall demand will continue to exceed supply which means that some patients may still have difficulty filling Wegovy prescriptions."

The spokeswoman continued, "We are confident that these actions will help even more people living with obesity in the U.S. – beyond the one million we have already served – and remain committed long-term to partner, raise awareness, and advocate to change how obesity is understood, diagnosed, and treated."

All of the medications -- Wegovy, Ozempic, Mounjaro and Zepbound -- work by slowing down the movement of food through the stomach and curbing appetite, which can lead to weight loss.

Side effects of the drugs can include severe nausea and constipation.

The drugs' popularity has grown over the past two years, leading to intermittent shortages as the manufacturers try to meet demand.