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 U.S. 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 U.S. 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.

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.

The new year is usually a time to jump-start healthy habits. But millions of Americans need medical assistance to manage their weight, and they likely aren't getting it.

"We're still in a state today where the average primary care doctor, the average psychologist, even the average dietitian doesn't really have a strong background in obesity management to support most of their patients," said Dr. Scott Kahan, the director of the National Center for Weight and Wellness.

Kahan says over the last decade, the FDA has approved about six weight-management medications. The problem is that some of those medications require injections, and insurance may not cover them. Also, few people or professionals know about them.

"While some of them can do just fine without medication and others might do very well with bariatric surgery, there are quite a lot that are very good technical candidates for medications and would likely have a much better course in terms of managing the obesity and in terms of long term health and prevention," Kahan said.

Kahan says people who are ideal candidates for weight management medication include people who are roughly 30 pounds or more overweight and have health-related issues like diabetes, high blood pressure, joint pain or sleep issues.

"Those are especially important considerations, where the obesity is getting more in the way of your life and your health and where a modest amount of weight loss may significantly improve many of those things," Kahan said.

The FDA could consider another weight management drug for approval as early as this year.

A small device could one day be an alternative to gastric bypass surgery for people who are dangerously overweight.

Researchers at Texas A&M University created the device that is implanted into the patient's stomach. It makes you feel full by using light to stimulate the nerve endings that control hunger.

The device is controlled by a remote source, much like a pacemaker.

The lead researcher behind the device says it could be a safer option than a more invasive surgery.

“Gastric bypass surgery is the most popular approach to treat obesity. The thing is, it’s not a cost-effective solution, plus it involves side effects,” said Sung Il Park at Texas A&M University.

He says his team also gained a better understanding of how our body feels hungry.

Conventional wisdom is when the stomach expands, signals are sent to the brain that a person is full.

Park's team found it is possible to stimulate those nerves to make the body feel full, even when the stomach is empty.

“To be able to activate and manipulate individual neurons, we have to express light sensitive protein to the targeted region. So, such related research is ongoing,” said Park.

He says so far, they haven't found any technical problems with the device.

He says it could be a few years before it might be available for widespread use because they still have more research to do. And then it must go through the Food and Drug Administration’s approval process.