8 Common Myths About Weight Loss Drugs Like Wegovy and Zepbound Debunked

• Misconceptions about the benefits and risks of GLP-1 drugs like Ozempic, Wegovy, Mounjaro, and Zepbound are common.
• Not all GLP-1 drugs are the same, and different medications may affect people differently.
• Before starting a GLP-1 drug, talk with a healthcare professional about the potential risks and benefits.

It likely won’t surprise you to hear that the GLP-1 drugs semaglutide (better known by the brand names Wegovy and Ozempic ) and tirzepatide (sold under the brand names Monjouro and Zepbound ) were among the top 10 most popular drugs by U.S. spending in 2023.

The medications have been heralded has game-changing treatments for diabetes and obesity. But as their popularity has grown, so too have persistent myths and misinformation about them.

“The reality is that each of these is prescribed to achieve different health goals, and like any medication, they each come with potential risks that patients should be educated on in order to make informed decisions with their healthcare providers,” says HaVy Ngo-Hamilton , Pharm.D., pharmacist and clinical consultant for BuzzRx.

In an effort to clarify common misconceptions, Healthline spoke with experts who helped identify and debunk the eight most common myths currently being shared about GLP-1 drugs.

Myth: Taking a GLP-1 drug guarantees significant weight loss

The short answer: “Nothing guarantees weight loss,” says Dr. Mir Ali, MD, a board certified bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center.

Ali notes that these drugs certainly have a high success rate for aiding with weight loss, primarily because of their ability to slow stomach emptying, helping people feel fuller longer.

In a clinical trial , patients who took weekly 2.4 mg doses of semaglutide lost “clinically significant weight” within 68 weeks.

A 72-week trial for tirzepatide suggested that 91% of people who took the maximum 15 mg dose saw a weight reduction of 5% or more. Over half of the participants (57%) lost 20% of their body weight.

Those numbers are good, but they are not perfect. Doctors generally recommend patience — to a point.

“The FDA has given us guidelines when using these medications, in that we expect at least 5% total body weight loss at 12 weeks,” says Dr. Janese Laster, MD , who is board certified in internal medicine, gastroenterology, obesity medicine, and nutrition. She is also the founder of Gut Theory Total DigestiveCare .

If this weight loss doesn’t occur, Laster says a healthcare professional will discuss lifestyle factors, including:

• Dosing
• Whether the patient is taking the medication correctly
• Diet
• Exercise

However, a small percentage of patients won’t respond, which doesn’t mean they did anything “wrong.”

“Obesity already carries a lot of unnecessary societal stigma and shame, so it’s important that patients understand that it is largely out of their control regarding who is a responder or a non-responder,” says Dr. Michael Glickman, MD , the CEO and founder of Revolution Medicine. “It is likely a genetic explanation or…your unique physiology.”

Though Mounjaro and Ozempic are approved for the treatment of type 2 diabetes, one 2022 narrative review suggested that individuals living with type 2 diabetes who take these drugs may see less weight loss.

Myth: You don’t have to exercise while taking GLP-1 drugs

Even the label says otherwise.

“If you look at the package insert for Wegovy or Zepbound, the instructions are to use these medications with a ‘reduced calorie diet and increased physical activity,’” Ngo-Hamilton explains. “In reality, the amount of diet and exercise will vary among users, leading to various degrees of weight loss. However, consistent physical activity is vital to achieve and maintain the desired weight loss.”

A 2023 article suggested that physical activity is important in helping patients maintain lean muscle mass, which can be lost along with weight. Glickman emphasizes that resistance training is especially critical for these efforts.

“If we are not exercising during the weight loss journey, ultimately our metabolism can suffer because patients will lose a significant amount of muscle mass too,” Glickman says.

Myth: You don’t need to eat a healthy diet if you’re taking a GLP-1 drug

Again, the label suggests the opposite, but social media captions may not.

“These medications are not magical, despite what is seen in the media/social media,” Laster says.” Patients will not have success if they do not also make lifestyle and diet changes. Nonadherence to dietary changes is one factor we consider if a patient is not losing weight as we expect on these medications.”

Glickman suggests a plant-forward or Mediterranean-style diet , which emphasizes certain fats, lean and plant-based proteins, and leafy greens and deprioritizes ultra-processed and high-sugar foods and drinks.

Dietary choices are also important for reducing side effect risk and severity.

“Because these medications trigger insulin production, slow the emptying of the stomach, and cause you to feel full faster and for longer periods of time, eating unhealthy foods or larger portions of food may cause negative gastrointestinal side effects, including abdominal pain, nausea, or vomiting,” Ngo-Hamilton says.

Myth: Side effects are unbearable (or no big deal)

Ultimately, the severity of side effects is relative.

“Unbearable is a subjective term, and individual thresholds for discomfort may vary significantly from person to person, as may the side effects individuals experience while taking the medication,” Ngo-Hamilton says.

Backing up, Ngo-Hamilton says common side effects of GLP-1s include:

• Vomiting
• Nausea
• Diahrrea

She says the side effects are often temporary and resolve as the patient adjusts to the medication. Ali says that’s why providers gradually increase doses.

“If side effects are an issue, medications to counteract the side effects can be given,” Ali says, adding it’s unusual for a patient to stop taking a GLP-1 for side effects.

However, that doesn’t mean none do.

“If the side effects aren’t effectively controlled with symptom management and don’t decrease or resolve after three or more months on the medication with dosage increases, you should talk to your doctor about switching to a medication with a different mechanism of action or exploring a different category of weight loss drugs entirely,” Ngo-Hamilton says.

Myth: Using compounded GLP-1 drugs is just as safe as brand-name medications

Doctors advise using caution before opting to obtain compounded GLP-1 drugs.

“While compounded drugs are certainly an important — and sometimes necessary — option for patients who require access to a drug that is in shortage or otherwise commercially unavailable, these are formulated by specialty pharmacies combining active ingredients they source themselves,” Ngo-Hamilton says. “Unlike the brand name drugs that are clinically tested by the manufacturers for safety and efficacy according to FDA guidelines, compounded drugs are not held to those same standards and are not FDA-approved medications.”

Ali suggests discussing options with a healthcare professional and getting their take on compounded GLP-1 drugs and reputable pharmacies.

“If you are getting medication…through social media or questionable online sources, you may end up with something that does not work or, worst-case scenario, causes harm, ” he says.

Myth: Your insurance will cover the cost if you’re a prime candidate

Not always. Cost is a barrier for some individuals who would like to go on GLP-1 medication, and not all insurance will help cover it. Medicare does not cover GLP-1s for weight loss.

“Insurance coverage will vary by person and by insurance policy, and recently, more insurance plans have opted not to cover the cost of GLP-1 agonists, particularly those that are being prescribed for off-label use,” Ngo-Hamilton says. “For example, when someone doesn’t have type-2 diabetes, their healthcare provider prescribes Ozempic as off-label use for weight management.”

A month’s supply of Ozempic can cost about $1,000, similar to Zepbound’s prices.

“Prescription discount cards can be a helpful resource for patients whose insurance plans don’t cover these medications,” Ngo-Hamilton says.

Myth: All GLP-1 drugs are the same

They are similar but not the same . Even Ozempic and Wegovy, though both semaglutide, have some distinctions.

“Ozempic and Wegovy are both semaglutides, which stimulate the GLP-1 receptor to reduce appetite and slow stomach emptying,” Ali says. “Ozempic is indicated for diabetes, whereas Wegovy is for weight loss.”

The maximum weekly dose of Ozempic is 2.0 mg, while Wegovy’s is 2.4 mg.

Zepbound and Mounjaro have the same weekly dose (15 mg), and the lone distinction between them is that Zepbound is for weight management, and Mounjaro is for diabetes treatment. They are different from semaglutide but possess commonalities.

“Mounjaro and Zepbound are both tirzepatide which affects two receptors, GLP-1 and GIP, again reducing appetite and slowing stomach emptying,” Ali says.

Zepbound is “better” than Wegovy for weight loss

Some data suggests that patients will lose more weight on Zepbound than Wegovy. Eli Lily-conducted trials ( SURMOUNT-3 and SURMOUNT-4 ) indicated that people taking tirzepatide lost more than a quarter (26.6%) of their body weight in 84 weeks, which is more than the 15% of people taking Wegovy for 68 weeks lost.

The timeframe was different for these trials, and Glickman says experiences can vary, too.

“Not every patient tracks perfectly along the average weight loss curve,” Glickman says. “Some patients can be non-responders to one brand and responders to the other. Some patients can also be average responders to one brand and super responders — above average — to the other. It can be a little unpredictable.”

Currently, Glickman says that close monitoring is sometimes the best way to determine long-term fit. However, more research in precision medicine may change this strategy.

Takeaway

Misconceptions about the benefits and risks of GLP-1 drugs like Ozempic, Wegovy, Mounjaro, and Zepbound are commonly spread.

Though these medications can help people lose weight, not everyone responds to them.

Diet and exercise are still important factors for sustainable weight loss while taking a GLP-1 medication.

Before starting a GLP-1 drug, talk with a healthcare professional about the potential risks and benefits.