The risks of taking weight loss medicines like Ozempic

Sandra Weber, MD

Endocrinology

Medications like Ozempic, Wegovy, Mounjaro and Zepbound have been touted as miracle drugs when it comes to weight loss. Like all drugs, these weight loss medicines have side effects, and you have to balance the risk versus the benefit.

Endocrinologist Sandra Weber, MD, explained how these weight loss medicines work and the risks to consider before taking them.

How do medicines like Ozempic work?

Ozempic is in a class of medication called glucagon-like peptide-1 agonists (GLP-1), which has been used to treat type 2 diabetes and obesity by mimicking a hormone in the gut that communicates with the brain, pancreas and liver. The medicine triggers receptors that cause you to feel full, decrease the amount of food the gut moves along, and lower your blood sugar.

Although they’ve recently gotten a lot of attention, GLP-1 medications have been around for about a decade. For example, liraglutide has been available for the treatment of diabetes and weight loss. It’s marketed as Victoza for diabetes and as Saxenda for weight loss.

Semaglutide and tirzepatide are newer and longer acting drugs. Semaglutide is marketed as Ozempic for diabetes and Wegovy for weight loss. Wegovy has a slightly higher dose of 2.4 milligrams compared to Ozempic’s maximal dose of 2 milligrams. Tirzepatide is marketed as Mounjaro for diabetes and as Zepbound for weight loss. They target two hormone receptors: GLP-1 and gastrointestinal peptide.

“As these medications have evolved, they’re getting more potent,” Dr. Weber said. “We are seeing a little bit more improvement in glucose control, but we’re seeing significant improvement in weight loss, which is what’s made them so much more popular.”

They’re also getting easier to use, going from a twice daily injection to once a week injection.

What are the risks associated with these weight loss medicines?

“The medicines are predominantly well tolerated, but the first doses are usually the most difficult,” Dr. Weber said. “Sometimes nausea and vomiting develop with those initial doses and then each dose after that gets better.”

To avoid overstimulating the receptors that cause this reaction, the medicines are started at very low doses and gradually increase to the highest tolerated dose. This is because the medications can affect how the gut processes food.

“The whole continuum can be slower,” she said. “Some people may have issues with the stomach emptying and have indigestion or more retained foods in the stomach area that take longer to process and move into the intestine. Many people also develop constipation.”

Another issue people are running into when they start these drugs is the medication becoming unavailable because demand is outpacing supply. Patients often have to switch to another drug that might not be covered by their insurance. These medications are very expensive, and it can take time finding an alternative.

“We are seeing horrible shortages, and these are not medications that you want interrupted because you can experience side effects again,” Dr. Weber said. “It was not designed that you switch from one medicine to the other. It puts patients on a roller coaster that they should not have to go through.”

She said it’s also important to remember that these medications are meant to be used on a long-term basis to treat the chronic condition of obesity. They’re not appropriate for quick weight loss, like if you want to lose 10 pounds before a wedding.

Is it safe to purchase these drugs online or from compounding pharmacies?

It can be tempting to buy the medicine from an online prescriber, but not knowing where it’s coming from or what is in the drug is risky.

You also want to be sure you’re taking the medications under the guidance of a physician who is meeting with you and working with you on lifestyle modifications such as diet and exercise. Another common side effect of GLP-1 medicines is a decrease in muscle mass, so physicians will recommend a diet that includes healthy proteins, as well as resistance training.

What is the outlook for these weight loss medicines?

Dr. Weber expects the medications to continue to improve in effectiveness.

“The next generation, which is now being studied, includes a monoclonal antibody so it lasts even longer and has a greater effect. MariTide is one that has the monoclonal antibody and is a once-a-month injectable.”