Jim Vondruska/Reuters
Wegovy is designed to be taken once a week by self-injection.
CNN  — 

Novo Nordisk, maker of the weight-loss drug Wegovy, said it would limit supply of starter doses as demand outpaces the company’s manufacturing capacity.

The supply interruptions aren’t expected to affect higher doses of the medicine for people who already take the drug, the company said in a statement posted Thursday on its Wegovy website. Novo Nordisk said it anticipates that many people will have trouble filling prescriptions at the lower initial doses through September.

The US Food and Drug Administration approved Wegovy for chronic weight management for people with a body mass index of 30 or more, or 27 or more for people with a weight-related condition like high blood pressure. It and sister drug Ozempic, which is approved for type 2 diabetes, have soared in popularity, sweeping across social media sites and garnering mentions at the Oscars and on “Saturday Night Live.”

“With rising rates of obesity, there is an increased demand” for drugs like Wegovy, said Dr. Priya Jaisinghani, an endocrinologist and obesity medicine specialist at NYU Langone Health. She said that she hasn’t had issues filling prescriptions of Wegovy recently but that she had in the past.

Wegovy is one of the brand names for semaglutide, which is part of a class of drugs that mimic the effects of an appetite-regulating hormone called GLP-1. They stimulate the release of insulin, which helps lower blood sugar, and slow the passage of food through the gut. The FDA approved semaglutide for diabetes as Ozempic in 2017 and for weight loss as Wegovy in 2021. But Wegovy soon went into shortage amid production problems, and some supply problems have continued.

People who take Wegovy for weight loss must continue to use it to maintain the effects; dropped pounds can return when they stop.

Celebrities such as Chelsea Handler and Elon Musk have talked about using semaglutide or Wegovy. The Hollywood connection has been so strong that Novo Nordisk included in its “Frequently Asked Questions” section an inquiry about why celebrities can get Wegovy when it is unavailable for others. The drugmaker noted that it can’t control which specific people receive its medicines but said “we reinforce who our medicines are intended to treat based on their clinical trials and FDA-approved indications.”

Interest is so high, Novo Nordisk said, that it will pause some promotion of Wegovy “to avoid stimulating further demand.”

Wegovy is designed to be taken once a week by self-injection. Patients start on the lowest dose, 0.25 milligrams, and move up to the maintenance dose, 2.4 milligrams, over the course of 16 weeks. The lowest three doses are the ones Novo Nordisk says will have limited supply.

This gradual dosage increase is designed to limit gastrointestinal side effects like nausea, vomiting and diarrhea.

“They are very challenging to take,” said Dr. Ethan Weiss, a preventional cardiologist at the University of California San Francisco and entrepreneur-in-residence at venture capital firm Third Rock. Still, he notes, “they are a really valuable option for those who have struggled and don’t want or are not eligible for surgery.”

Novo Nordisk said hundreds of thousands of people in the US are on Wegovy, and it noted that an additional contract manufacturer recently started production to help increase supply. In the meantime, it recommends that people currently taking Wegovy contact their pharmacy about refills at least a week or two earlier than normal, and try multiple pharmacies if the first one doesn’t have the drug. It also suggests that health-care providers consider the potential supply disruptions when considering whether to start new patients on Wegovy.

Although Ozempic and Wegovy contain the same key ingredient, Novo Nordisk noted that “the products are not interchangeable”; they have different indications, dosages, prescribing information and paces of titrating up.

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Ozempic has had supply issues as well for people with diabetes, even prompting British Columbia to move to restrict its sale amid a surge in prescriptions, many from Americans seeking the drug across the border.

There have also been supply constraints on a similar medicine made by Eli Lilly, Mounjaro, which is approved only for diabetes, Jaisinghani said.

She recommended against seeking weight-loss drugs through other avenues like medical tourism and compounding pharmacies.

“It’s very important to speak to your doctor regarding your plan on how and where you are obtaining medications to make sure they are the FDA-approved formulation and safe for use,” she said.