What You Need to Know About Drugs Like Ozempic Being Used for Weight Loss

Obesity is among the world’s most common health conditions, but for years medicine has had few effective approaches to offer short of surgery. That’s why there’s been so much excitement about a new class of drugs that’s helping patients shed dozens of pounds at far lower risk; one of the treatments has been shown to reduce heart attacks and strokes. Drugmakers are racing to scale up production of the few medications approved so far and test new versions. Yet there are big hurdles that could keep the medications from many or most of the billion or so people worldwide considered to have obesity: They cost a lot, insurance coverage is spotty and patients may need to take them indefinitely to avoid regaining weight.

1. How do these drugs work?

They mimic a hormone, GLP-1, that’s released after eating and works in the brain to reduce appetite and increase feelings of satiety. The drugs, known as glucagon-like peptide 1 receptor agonists, were first developed for Type 2 diabetes. The hormone also prompts the pancreas to release insulin after meals, which brings down blood sugar, also known as glucose; people with diabetes have trouble regulating glucose levels. The drugs began to be used as obesity treatments after patients with diabetes who took them lost weight.

2. What’s available?

So far, only two GLP-1 injections have been approved for obesity treatment in the US: Saxenda and Wegovy, both from Novo Nordisk A/S. Another new shot, Eli Lilly & Co’s Mounjaro, which replicates the effects of GLP-1 and another hormone called GIP, is currently approved in the US for diabetes and is expected to undergo regulatory review soon for obesity. Some doctors are also prescribing GLP-1 drugs approved only for diabetes, including Novo Nordisk’s Ozempic, as weight-loss medications. After Ozempic was popularized on social media platforms such as TikTok, with influencers boasting of weight loss, shortages developed.

3. How effective are they?

Early versions of the GLP-1 drugs produced only modest weight loss when taken by people with diabetes. Newer drugs have built on that. A study of Saxenda, for instance, found that it induced loss of about 5% of body weight. The two medicines currently considered most effective are Wegovy, also known as semaglutide, and Mounjaro; in trial results, they helped patients lose about 15% and 21% of their body weight, respectively. In the studies, the drugs also helped improve patients’ blood pressure and cholesterol levels. By comparison, bariatric surgery, in which the digestive system is modified to aid weight loss, can produce a 30% weight loss, but it is considered riskier and has a higher immediate cost. Wegovy’s maker Novo Nordisk A/S said Aug. 8 that, in comparison with a placebo, the drug reduced the risk of cardiovascular events by 20% in people who were obese or overweight and have a history of heart issues.

4. Are they safe?

Since drugs in this category have been used for nearly 20 years to treat patients with diabetes, their safety profile is considered relatively well-established. Most of their known side effects aren’t serious, though they can be unpleasant: Between 25% and 45% of patients reported experiencing nausea, diarrhea, vomiting or constipation when taking Wegovy. In its safety information, the medication lists a potential risk of thyroid cancer, and people with a family history of certain serious conditions are advised not to take it. Patients may also experience inflammation of the pancreas or kidney injury. But the new treatments haven’t been studied long-term in patients taking them for obesity.

5. What are their limitations?

Studies have found that patients who stop taking Wegovy regain a majority of their lost weight. That’s the drawback of almost all weight treatments: Dieters regain more than 80% of their lost weight within five years, sometimes adding more, while as much as a quarter of those who undergo bariatric surgery experience significant weight regain.

6. What are other barriers to wider use?

The biggest one may be price. Wegovy costs about $1,400 a month in the US, a cost that so far falls mainly on patients: Only 20% to 30% of privately insured patients have coverage for the drugs, and the Medicare insurance program for the elderly doesn’t cover obesity drugs at all. Coverage is also limited abroad, though payers in some countries, like Canada, Switzerland and Colombia, will reimburse for Saxenda in some cases. The financial burden and side effects suggest that few would be able to use obesity drugs for life.

7. What’s next?

The success of these drugs has set off a boom in research. There are now more than 50 anti-obesity drugs in clinical development from about 40 companies, according to Bloomberg Intelligence. Many target GLP-1 and other hormones, including GIP, glucagon and amylin. Annual sales of anti-obesity drugs, which today total about $2.2 billion, could reach more than $40 billion globally by 2030, according to Bloomberg analysts.

The Reference Shelf

• A Bloomberg Intelligence report on the battle between Novo Nordisk and Eli Lilly for dominance in the booming field of anti-obesity drugs.

• Losing It, a series from Bloomberg’s Prognosis, investigates how we got weight loss so wrong — and whether there’s a better way forward.

• Related Bloomberg stories on the new drugs, pharma companies entering the space and the impact of shortages.

• Medical guidelines describing who is eligible for these drugs.

More stories like this are available on bloomberg.com