Interested in the new weight loss drugs? Here are 5 things to know

By Andrea Kane, CNN

(CNN) — Being on a diet sometimes feels like an American pastime: If you haven’t experienced the “pleasure” of it, then it’s almost certain that your BFF, baby brother, aunt or someone else in your close circle of family and friends has.

It’s probably no coincidence that government statistics show that more than 30% of Americans are overweight and more than 42% have obesity. A related government survey found that almost half of US adults said they have tried to lose weight in the last 12-month period. The top two methods were exercising and eating less food, followed by consuming more fruits, vegetables and salads.

People want to lose weight to look a certain way “now,” and they also want to live longer and healthier lives, with a lower risk of developing serious health conditions in the future.

But anyone who has ever dieted can tell you that losing weight is hard and that long-term weight loss requires sustained effort, which can sometimes feel Herculean, even impossible.

A new class of medications — called glucagon-like peptide 1 receptor agonists, or GLP-1s — has taken the country by storm because these drugs seem to make weight loss more effortless. They often quiet the “food noise,” or brain chatter about food, that makes it so hard to stick to those all-important lifestyle changes.

Their brand names have become household words, seemingly overnight. Ozempic and Wegovy have semaglutide as the active ingredient, while Mounjaro and Zepbound contain tirzepatide.

The podcast Chasing Life With Dr. Sanjay Gupta unpacks the ins and the outs of these new medications to give listeners a crash course on what they are all about. You can listen below.

Originally developed for type 2 diabetes, medications such as semaglutide and tirzepatide work by mimicking the hormone glucagon-like peptide 1, which is released in our gut when we eat.

“It’s a peptide that is secreted by our intestine, and it’s normally very short-acting, and it’s degraded by other enzymes in the body really quickly,” obesity specialist Dr. Jorge Moreno told CNN Chief Medical correspondent Dr. Sanjay Gupta on the Chasing Life podcast recently. Moreno, an assistant professor of medicine at Yale School of Medicine, treats patients looking to manage their weight.

He explained that GLP-1 is a nutrient-stimulated hormone that activates when you eat, telling your body you just had food. “(It goes) into the area of the brain that is the hypothalamus … and (it tells) your brain, ‘You’ve had food, stop eating,’” he said.

The medications attach to the same receptors as the GLP-1 hormone but are longer-acting. “And so, they keep this mechanism working consistently,” Moreno said. “They basically decrease your appetite by signaling in the hypothalamus that you’re full.”

Both the hormone and the medications also trigger other actions, such as slowing down the movement of food through the gut and telling the body to release more insulin. Tirzepatide also can attach to the receptors of another related hormone, called GIP for short, which makes it a bit more powerful.

If you are considering starting one of these medications, Moreno recommends keeping these five facts in mind.

These meds are not for everybody

At the moment, the weight loss versions of semaglutide (Wegovy) and tirzepatide (Zepbound) are approved to treat people with obesity, not those looking to shed a few pounds.

“Patients should be aware that these are treatments for a chronic medical condition known as obesity,” Moreno said. “I think it’s important to realize that obesity is a chronic disease that is relapsing (and) that requires long-term treatment.”

He said that Wegovy and Zepbound are — in the parlance of the US Food and Drug Administration — “indicated” for use in people diagnosed with obesity, or those with a body mass index of 30 and above. They’re also indicated for people with a BMI of 27 and above who also have a weight-related medical conditions such as type 2 diabetes or high blood pressure. (Semaglutide, sold as Ozempic, and tirzepatide, sold as Mounjaro, are indicated only for people with type 2 diabetes.)

If you haven’t been given one of these diagnoses, you may have trouble getting a prescription, let alone getting your health insurance to cover the hefty price tag.

They work

These drugs are pretty effective in helping many people lose weight. They are filling a gap between earlier weight loss drugs, which Moreno said help people lose on average between 5% and 10% of their body weight, and bariatric surgery, an invasive procedure that he said helps people lose on average around 25% to 30%. 

“It’s important to know that these medications are efficacious,” Moreno said. “On average, with semaglutide, the weight loss average can be close to 15%. Tirzepatide is reaching bariatric surgery levels of weight loss, with a weight loss close to 21%.”

They’re also safe

This class of drugs — GLP-1 receptor agonists — has been used since 2005 to treat diabetes, so it has a relatively long track record for safety.

“It’s also important to understand that these are safe medications,” Moreno said. “Yes, like any other medication, these medications have side effects. Most commonly in the patients I see (are) nausea, constipation and acid reflux — we call it GERD.

“Now, rare side effects — and by rare I mean less than 1% of the time — include things like pancreatitis, which is … inflammation of your pancreas — extremely rare,” he said. But he added that as these drugs grow in popularity, “a rare event becomes a little bit more obvious, because there (are) more people using these medications.”

Treatment requires follow-up

Like any chronic disease, treatment requires a partnership with your doctor.

“Just like diabetes, just like hypertension, obesity management requires close follow-up. This is not a one-and-done conversation with your doctor,” Moreno said.

He recommended following up every month or every other month. “You need to advocate for yourself,” he said. “You should definitely be followed closely, because this is a long-term strategy to help you.”

It’s not a panacea

“One medication is not going to fix everything. One medication is not going to be ‘it,’” Moreno said, noting that these drugs are just one component of a comprehensive plan to treat obesity.

“Lifestyle is still important,” he said. “This is the time to start exercising. This is the time to start changing some eating patterns that will be beneficial for weight loss. … I think that’s really something that patients should take away.”

We hope these five things help you understand how these new meds work and what to keep in mind when taking them. Listen to the full episode here to learn more. And join us next week on the Chasing Life podcast when we explore the business side of these medications.

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CNN Audio’s Grace Walker contributed to this report.