Taking a weight-loss medicine can be exciting and scary at the same time. Medicines called semaglutides — better known by the brand names Ozempic and Wegovy — have been shown to help people lose about 15% of their body weight.

But they're not a quick solution. Andres J. Acosta, M.D., Ph.D., a Mayo Clinic expert in treating obesity, says that these medicines are not "a magic pill — or in this case, a magic injection."

Here's why.

Medicine isn't an easy way out

To lose weight and keep it off, you still need to adopt a healthier lifestyle. Medicines are a tool to help your body lose weight, not a quick fix or substitute for healthy habits.

"The diet is still key," says Dr. Acosta. "What this medication is doing is suppressing your appetite, so you don't feel that hungry, so you can eat less. So diet is important."

He recommends sticking to a healthy, low-calorie, high-protein diet to ensure healthy weight loss that you can keep off for a longer time.

Weight-loss medicine isn't right for everyone

"The FDA approved these medicines for people with a BMI greater than 30 or a BMI greater than 27 with obesity-related diseases, such as diabetes or hypertension," says Dr. Acosta. Body mass index (BMI) uses weight and height to estimate body fat.

Depending on your weight, medical history, current medications and stage of life — for example, if you're pregnant or breastfeeding — weight-loss drugs may not be for you.

Additionally, Dr. Acosta and other Mayo Clinic researchers have found that semaglutides may work better in people who have certain genes that affect hunger. Their research suggests that genetic testing could help narrow down who will benefit most from these weight-loss drugs.

Medicine can be expensive

Drugs like Ozempic can be pricey — and they're not always covered by insurance. Talk to your insurance company about your coverage before you commit to a treatment plan.

There are side effects

Semaglutides commonly come with mild side effects like nausea, constipation and diarrhea. These symptoms may be worse if you feel overly full.

"It's important to eat less to avoid excessive fullness," says Dr. Acosta.

Serious side effects like kidney problems or inflammation of the pancreas happen rarely. Another serious risk linked to these drugs is low blood sugar, called hypoglycemia. But this risk usually increases only when you're also taking insulin or another drug known to lower blood sugar.

Treatment requires regular follow-up

If you take weight-loss medicines, you'll need to meet with your healthcare team on a regular basis. During these appointments, you'll review your lifestyle habits and how well the medicine is working for you.

Your dosage or medicine may need to be changed or stopped if you aren't getting results or if the side effects are severe.

Stopping medicine affects weight

Some people think that once they reach their goal weight, they can stop taking the medicine and stay at that weight. But that's not the case if they haven't been eating healthy foods and exercising.

"The studies have shown that you will likely regain weight if you did not adopt lifestyle changes," says Dr. Acosta.