Interest has exploded in a weight loss drug that was initially developed to help diabetics control their blood sugar.

The drug, semaglutide, is a weekly shot sold under the brand names Ozempic and Wegovy. Only one, Wegovy, is approved by the FDA as a weight-loss drug to treat obesity. Ozempic is not approved for weight loss, but patients have reported getting it prescribed off-label for that purpose. Celebrities have touted their use of it. Business journals covered its threat to the dieting industry.

The rise in interest has driven both drugs into shortage.

The FDA hasn’t approved Ozempic just for cosmetic weight loss because of the risks that come with the drug. However, being overweight can eventually lead to a wealth of problems including heart disease, diabetes, orthopedic problems and some cancers.

Studies are under way that could lead to huge numbers of people who have no current health issues beyond high weight becoming eligible for Ozempic and similar drugs to lose weight.

Here are some things to know about Ozempic and its sister drugs.

Q: What is Ozempic?

A: Ozempic is one brand name for a relatively new group of drugs that trick the brain into thinking that the body just ate food. The technical term for the drugs is “GLP-1 agonists.”

The drug company Novo Nordisk makes its GLP-1 agonist, semaglutide, under the brand names Ozempic, Wegovy and Rybelsus.

Another GLP-1 agonist is the drug brand Mounjaro, made by the drug company Eli Lilly.

Q: How do these drugs work?

A: After the drug is plugged into the brain, the brain stops hunger signals. In addition, the brain triggers the body to produce the hormone insulin, so the insulin goes into the bloodstream to manage the imaginary food and its sugars. That’s something that can help diabetics.

Q: How is Ozempic different from its sister drugs?

A: Ozempic is approved for use only in patients with Type 2 diabetes. Wegovy is approved for overweight patients — that’s patients with a body mass index of at least 27 —who also have a weight-related condition such as type 2 diabetes, high blood pressure or high cholesterol.

Wegovy is also approved for patients who aren’t diabetic but who are obese, with a body mass index of 30 or greater.

Q: What are Ozempic’s health risks?

A: Ozempic comes with several warnings about possible side effects, some of them dangerous. The most common side effects reported are gastrointestinal, such as nausea and vomiting. But they may be more serious: The FDA advises doctors to stop Ozempic immediately if pancreatitis — an inflammation of the pancreas — is even suspected. The FDA also says Ozempic should not be taken by some patients, like those with a family history of a type of thyroid cancer called medullary thyroid carcinoma.

Q: How much does Ozempic cost?

A: CVS and Walgreens pharmacies contacted by the AJC this week quoted prices of more than $1,000 for one month’s supply of 1 mg Ozempic, without insurance.

Q: Will my insurance pay for any of these drugs for weight loss?

Ozempic is often covered. Wegovy is often not covered.

Q: What happens if you go off Ozempic or its sister drugs?

A: The drug stops working if you stop taking it and appetite and weight return. A study of people on the higher dose of semaglutide, found in Wegovy, found that after they stopped taking it the study participants on average regained two-thirds of the lost weight back.

Q: What’s next for Ozempic?

A: More research is going on. The research might indicate GLP-1 agonist drugs are helpful for a wider range of people.

Q: What other controversies are on the horizon?

A: If Ozempic is deemed to be safe and effective for weight loss in the general population, that presents the question of whether insurance, Medicare and Medicaid should pay to provide the drug to large numbers of people if it has a huge widespread health benefit.

FDA Commissioner Robert Califf addressed the issue in an interview this week with the The Atlanta Journal-Constitution. “What if the benefits outweigh the risks substantially for people that have obesity without diabetes? We don’t know that, but the trials are being done,” Califf said.

“We have a growing explosion of obesity and diabetes in populations, like the Medicare and Medicaid populations, who can’t pay large out-of-pocket costs for medicines. But if the data in that population looks as good as it does in people with diabetes and vascular disease, there may be offsetting benefit to society, and the individual, in not having heart attacks and strokes and not needing orthopedic procedures.”

“Lower income, less well educated, minority populations tend to have more obesity and more obesity related diseases,” that lead to bad health outcomes. “And so there’ll be an issue. It won’t be in FDA’s lane, per se. Our job is to get the evidence as good as it can be.”