The Side Effects of Wegovy and Ozempic

A well-known diabetes drug has gotten a lot more popular over the last two years. In June 2021, Wegovy, a new formulation of semaglutide, the active ingredient in the diabetes drug, Ozempic, was approved for weight loss, even in those who don’t have diabetes. While it’s only indicated for people with obesity, celebrities with seemingly healthy weights have claimed to be giving themselves the at-home injections in hopes of fitting into particularly form-fitting outfits for special events.

If you so much as Google “Wegovy” even once, you’ll likely start seeing ads on social media for telehealth companies that help manage weight, and of course, have doctors ready to prescribe a variety of drugs for you, including Wegovy.

In the summer of 2021, enthusiasm was high. MedShadow Foundation founder, Suzanne Robotti, wrote an article about the drug in July of 2021, and patients quickly filled the comments section with stories of both dramatic weight loss and debilitating side effects.

But with more prescriptions come more reports of side effects. In particular, a Reuters investigation found 265 reports of suicidal behavior in individuals taking the drug sent to the FDA database, which regulatory agencies in the US and Europe are now investigating.

Challenges in Treating Obesity

For decades, we’ve been living in an obesity epidemic. 

Body mass index (BMI) is a problematic measure of the health of your weight, but it’s still used to identify those that are overweight or fall in the “obesity” category. The Centers for Disease Control and Prevention (CDC) offers a simple BMI calculator here. Everyone’s body is different, however. The CDC explains that for most people, a BMI below 18.5 is considered underweight. A BMI between 18.5 to and 25 is considered healthy. A BMI between 25.0 and 30 denotes someone who has overweight, and a BMI over 30 is to signify that someone has obesity. About 41% of adults fall into that last category, obesity, according to the CDC.

And it’s not just adults. Nearly 20% of kids age 2 to19 have been defined as “having obesity” in the U.S. Rates, according to the CDC, are highest among Hispanic children and non-Hispanic Black children, as well as families with lower incomes. The condition is linked to an increased risk of myriad illnesses from heart disease to cancer.

For some people, increasing physical activity and making dietary changes can improve health, but not enough to reverse obesity. 

Melanie Jay MD, a pediatrician and obesity researcher at NYU Langone points out that, while diet and exercise play a crucial role in maintaining a healthy weight,  there’s also a strong genetic component to obesity risk. Your environment can also contribute to obesity, in that both genetics and environment impact the terms of availability of healthy food and the existence of endocrine disrupting contamination, can influence your weight. 

How Do Wegovy and Ozempic Work?

Wegovy is known as a GLP-1 receptor agonist. Essentially, it mimics a hormone that helps us feel full and tells our stomach to take its time emptying the food through the digestive system.

“The main mechanism of action is in the brain,” says Daniel Weghuber, MD, a pediatrician at Paracelsus Medical University in Austria, who was the primary author on the latest trial of Wegovy in teens. “Patients will tell us that, now that they’re on the drug for the first time ever, they’re in the position to adhere to lifestyle recommendations that they have understood all the time.”

Weghuber has a conflict of interest in leading the study for teens. He notes that NovoNordisk, the company that manufactures Wegovy funded the study, and covers his travel and attendance at conferences that are relevant to the work, but he does not receive other payments or fees for speaking at those conferences from the company.

When you’re taking a GLP-1 drug such as Wegovy, doctors say you’ll likely feel fuller after eating much smaller quantities of food than you’re used to consuming.

How Long Will It Take Me to Lose Weight on Wegovy and Ozempic? 

In one study, patients who used Wegovy while making healthy changes to their diets and physical activity lost about 6% of their body weight in the first 12 weeks, 10% after 20 weeks, and 15% at the one year mark. They started to plateau in weight loss around week 60 on the medication.

Wegovy vs. Ozempic

Drugs that act like GLP-1 (glucagon-like peptide-1) have been used to treat diabetes since 2005. As patients and doctors started to notice unintentional weight loss that accompanied use of the drugs, scientists started testing these types of drugs for that explicit purpose, rather than just for diabetes treatment.

Wegovy is the first semaglutide FDA-approved for weight loss, but another injectable semaglutide, Ozempic, made by the same company (NovoNordisk), approved in 2017 to treat type 2 diabetes, has regularly mentioned the potential for patients to lose weight in its ads since 2018. The televised commercials stated that a study showed that adults lost up to 12 pounds on average while they took the drug for diabetes (with the caveat in small print, of course, that it is not a weight-loss drug). 

Both drugs contain the same active ingredient, semaglutide, but Wegovy is available in higher doses than Ozempic, so you would, in theory, lose weight faster if you can tolerate the higher doses of Wegovy.

Prescription Medications for Weight Loss

There are five other drugs approved for weight loss, but experts say their impacts are modest compared to Wegovy. The FDA is currently evaluating another drug for treating obesity, called Mounjaro. The drug was approved in 2022 for diabetes, and experts believe it is likely to be even more effective than Wegovy for weight loss because it contains a GLP-1 agonist, as well as a second ingredient that increases feelings of fullness and lowers appetite. A decision on its approval is expected later in 2023.

Other FDA-Approved Medications for Weight Loss Include: 

• Saxenda (liraglutide)
• Xenical, Alli (orlistat)
• Imcivree (setmelanotide)
• Contrave (Bupropion-naltrexone)
• Qsymia (Phentermine-topiramate)

What Are the Most Common Side Effects of Wegovy and Ozempic?

The side effects are significant for both drugs. About 20% of adult trial patients dropped out of the trial due to nausea, diarrhea, and constipation. But more may stop taking Wegovy outside of the trials, because, as Jay says, clinical trials are designed to provide the patients with support and education about how to manage nausea and other effects that people in the real world may not get. 

“We don’t have data on it,” she says, “but I think a lot more people in the real world go off of it.”  

In both the adult and adolescent clinical trials, patients commonly reported the following side effects of Wegovy:

• Nausea
• Diarrhea
• Vomiting
• Heartburn
• Rashes
• Hives
• Loss of interest in alcohol

Rapid weight loss, in general, can cause: 

• Muscle mass which fades along with the weight  
• “Ozempic face” – sagging facial skin due to loss of fat. Fat keeps skin plumped and elastic
• Hair loss was reported by 4% of the people in one trial, 3% in another trial  
  

What Are the Rare Side Effects of Wegovy and Ozempic? 

• A possible increased risk of medullary thyroid cancer
• Intestinal obstruction
• Pancreatitis (inflammation in your pancreas)
• Gastroparesis (a condition in which food stays in your stomach as if there is a blockage, even if there isn’t anything blocking the food from moving through your digestive system)
• Dehydration

The Most Dangerous Side Effects of Wegovy and Ozempic

A Reuters investigation in September 2023, found 265 reports of suicidal behavior in individuals taking the drug sent to an FDA database of adverse events, which regulatory agencies in the US and Europe are now investigating. Side effects can be reported to the FDA by anyone, including patients, doctors and family members. It’s possible that reports represent coincidental experiences of patients, rather than true side effects, but the data is monitored regularly, and when the agency notices a cluster or the same side effect, it is required to investigate any possible connection between the experiences and the drugs.

Additionally GLP-1 drugs could raise your risk for certain types of thyroid cancer, and the manufacturer recommends that people with a family history of medullary thyroid cancer, in particular, avoid the drug.  

Some researchers are drawing attention to the fact that one of the side effects of Wegovy and Ozempic is that they may increase your risk for an intestinal obstruction. That’s when food is blocked from making it all the way through your digestive tract, and you may need surgery to correct it.

A separate study in October 2023 found that people taking Wegovy or Saxenda (liraglutide) were at higher risk not only for intestinal obstruction, but also gastroparesis (delayed emptying of the stomach) and pancreatitis (inflammation of the pancreas that can cause vomiting and fevers,) than those taking Contrave, an older weight loss drug that works differently.

Any rapid weight loss regimen, including GLP-1 drugs, can cause you to lose muscle mass. Some scientists recommend making sure you incorporate weight training into your exercise routine to stay or become more toned.

Users have taken to TikTok to describe the nausea they’ve had with Wegovy and how they’ve handled it.

TikToker, Bossfidence, says she’s often extremely nauseous on the day she takes the injections. She also has migraine-like headaches and serious constipation. She has to remind herself to drink water to maintain hydration on Wegovy.

@bossfidence #semaglutide month 1 side effects that I have experienced! Follow me on Instagram for daily updates on my story ✨ #semaglutideforweightloss #wegovy #ozempic #mounjaro #weightloss #pcosawareness #pcos #pcosweightloss #insulinresistance ♬ original sound – Ashley | Bossfidence | GLP-1

In a May 2023 update, Bossfidence reported she’s experienced nausea, migraines, and constipation, but is happy to have lost about 2 pounds per week over the last 40 weeks, taking Wegovy and making healthy lifestyle changes.

@bossfidence I stopped havjng MOST side effects around montb 5/6 though 💉✨ #semaglutide #semaglutideforweightloss #compoundedsemaglutide #ozempic #wegovy #mounjaro #sideeffects #ozempicweightloss #wegovyshot #mounjarojourney ♬ original sound – Kim Kardashian

Other TikTokers have posted about lesser-known side effects such as rage and feeling cold.

The TikTokers often mentioned eating smaller meals more frequently in order to avoid nausea. Jay explains that one of the ways that the drug works is by keeping food in your stomach longer than it would typically stay there. In addition to eating smaller portions, she says high-fat foods can worsen side effects because they naturally stay in the stomach longer even without the drug. 

How Long Do Wegovy Side Effects Last?

In the first several weeks, many patients experience nausea, vomiting, constipation, and other gastrointestinal side effects. For some people, these effects lessened after the first six weeks or so, or with modifications like eating smaller, more frequent meals.

The Teen Wegovy Study

In November 2022, researchers published another trial, testing the drug in adolescents with obesity. If your teen has obesity, here’s what you need to know before talking to their healthcare provider about Wegovy or any other weight loss drug.

The study included 131 teens who were given Wegovy, and 62 who were given a weekly placebo injection for 68 weeks (about a year and four months.) Both groups met with dieticians as part of a lifestyle intervention. Those teens who were given semaglutide lost 16% of their BMI, compared to only 0.6% in the placebo group. Adults lost only 6-12.4% of their body weight in clinical trials.

A pediatrician called the results of the trial “mind-blowing”. It’s not clear why, but the drug seemed to cause even more weight loss in the teens than the adults. Weghuber says there’s some speculation that it could be because the “reward systems” that the drug acts on are more sensitive in the adolescent brains than those of adults.

“There were no new safety signals. The side effects in teens were very, very comparable to those that we have seen in adults,” says Weghuber, adding that the most common side effects were gastrointestinal distress, and rashes or hives. He did point out that five adolescents taking Wegovy developed gallstones, a known risk of rapid weight loss by any means.

Weghuber says that the gastrointestinal side effects were “expected,” adding that “they were more frequent in the first weeks, which is well known, and they fade away after six to eight weeks.”

He also emphasized that along with improvements in body weight, blood sugar, and other measures of health, the teens who took Wegovy reported better quality of life. 

“A 14-year-old does not ask ‘how are my cardiovascular risk factors?’ So it’s good to see quality of life is improving,” he says.

Who Can Get a Prescription for Wegovy?

In June 2021, the FDA approved Wegovy for weight loss in adults who have a BMI higher than 30, or who have a BMI between 27 and 30 alongside a weight-related condition such as diabetes or high cholesterol.

However, once a drug is approved, it can be prescribed “off-label” at the prescriber’s discretion. That means that a provider may suggest it for someone who has a BMI of 26 alongside a weight-related condition or for an adolescent if they see it fit. This is a frequent practice, especially in pediatrics, explains Jay, because fewer drugs are tested in children than in adults. However, she emphasizes that many people have had trouble getting insurance to cover the drug, and many doctors are unlikely to prescribe it to younger patients because they don’t perceive obesity as an emergency.

Since the drug was approved for weight loss, there have been shortages of Wegovy in the U.S. One of the TikTokers above mentioned she’d need to switch drugs within two weeks because a refill of her Wegovy was no longer available. Production was expected to ramp up in early 2023, and while the supply has increased, lower doses are still unavailable to many people as of May 2023.

But Jay still expects it’ll be difficult to come by for many people, shortage or not. 

“It’s very, very expensive and not covered by a lot of insurance,” says Jay.

What to Expect with Wegovy

Wegovy is a weekly injection that you can give yourself at home. You can place it in your arm, stomach, or thigh. TikToker bigdawg_lifestyle shows how in this video. (A reminder from MedShadow: The creator in this video discusses using a supplement to reduce side effects of Wegovy. Before you take that advice, be sure to research the companies manufacturing any supplements you purchase and discuss them with your healthcare provider before using them.)

When you start taking Wegovy, your healthcare provider may recommend starting with a low dose and raising it over several weeks. Most people, (90% of the patients in the adolescent trial) will end up taking the highest dose, 2.4mg.

As you take the drug, you will start to feel full very quickly after eating and may not have much of an appetite or even the desire to drink water. Dehydration can be a serious complication of diarrhea and vomiting, so staying hydrated is very important.

Long Term Side Effects of Wegovy and What Happens When You Stop Taking it

One MedShadow reader commented on Robotti’s early article about the drug and wrote that she’d been taking Wegovy and was getting close to her goal weight. She was thrilled with the progress, but she also wrote “I am terrified of what is going to happen to me when I stop the injections or when insurance cuts me off. Weight has been a lifelong battle that, for the first time in my life, I feel like I conquered. I’m not ready to give it up.”

There is an inherent risk with any new drug, because our knowledge of potential adverse events associated with the drug is limited by the length of the trials, which in this case, lasted one to two years. On the positive side, lower doses of semaglutide, the active ingredient in Wegovy, have been used to treat diabetes for several years now, though UpToDate, a site that aggregates research about treatments to support decision-making by physicians, notes that there have been very few trials lasting more than four years, so the long-term safety of these drugs is not yet established. 

A two-year study in adults showed that weight loss tended to plateau at about 60 weeks, but that those who continued to take the drug, maintained their healthier weights. 

Unfortunately, that does not mean that most people can take it for a year and stop taking it. 

“The effect does fade away as soon as you stop taking the drug,” says Weghuber. Typically, adults who stopped taking the drug started to gain weight again. We don’t yet know if this is also true for adolescents, but experts say they expect it will be.

“Obesity is a chronic disease and should be treated that way,” says Jay. You should be prepared for the possibility that you’ll need to take the drug long-term. 

Still, many people do stop taking semaglutide drugs. “We know that discontinuation rates are high,” says Rozalina McCoy, MD, MS, an endocrinologist and population health scientist at the University of Maryland School of Medicine. About 60% of patients who take semaglutide for weight loss stop within one year (though the rates are even higher for older weight loss drugs). This could be due to side effects, financial constraints or having reached one’s goal weight. McCoy points out that “many patients also experience a loss in quality of life because they lose all appetite and appreciation or enjoyment for food and food is such a big part of our lives,” which may cause them to stop taking semaglutide.

Unfortunately, stopping comes with its own problems. Since so many people who stop taking the drugs start gaining weight back again, they are at higher risk of developing disordered eating that can progress into serious eating disorders, explains Vashti Adams, MSW, a doctoral student at the University of Maryland School of Social Work studying weight inclusive care.

Semaglutide Shortages, Compounding Pharmacies and Counterfeit Drugs

With the prevalence of both diabetes and obesity, there have been frequent shortages of Ozempic and Wegovy. Compounding pharmacies—those that mix their own forms of existing drugs to customize doses, delivery methods or to combat shortages—have started to fill in the gap. Unfortunately, compounded semaglutide sometimes comes in different sizes or doses, leading people to accidentally give themselves far too much of the drug at once. They’ve ended up in the hospital with severe nausea, vomiting and dehydration. Some have needed anti-nausea medications and intravenous fluids to recover.

Worse, there are also counterfeit versions of semaglutide. Those are not made by approved compounding pharmacies, says Masha Yemets, PharmD, clinical toxicology fellow in the Maryland Poison Center in the University of Maryland School of Pharmcy. These drugs can contain inconsistent dosing or be tainted with other drugs. Researchers found insulin in some medications claiming to be semaglutide, which can cause dangerously low blood sugar (hypoglycemia).

“It does take a few extra steps to be sure what you’re getting is safe and effective,” says Yemets. Before using any semaglutide medication, check the following.

• Only use products you have a prescription for. You should not be able to get these drugs without speaking to a healthcare provider. Ideally, you should discuss it with your primary care doctor.
• Do not use products labeled “for research only.” These are not FDA-approved.
• Check your state’s Board of Pharmacies website to make sure yours is in good standing.
• Double check the dosage concentration and instructions on your bottle. If it’s compounded, it may be a different concentration than you’ve used in the past, meaning you’ll need to adjust your dose.
• Avoid products with the words “semglutide salts,” “semaglutide acetate,” and “semaglutide sodium.” These compounds are different from semaglutide and are not FDA approved.
• Compare your medications to photos in this FDA warning to ensure it’s not a known counterfeit.

Wegovy, Diabetes, and Heart Disease

Wegovy was originally approved for diabetes. The primary killer of people suffering with diabetes is CVD (cardiovascular disease) and a common side effect of diabetes is eye disease that can lead to blindness (diabetic retinopathy). Novo Nordisk, the manufacturer, was required to run a trial that focused on CVD, with a secondary consideration on diabetic retinopathy. 

The study, dubbed SUSTAIN 6, had mixed results, which were published in 2016. It showed a significant decrease in most of the CVD measurements, improving risk factors for those that tried the medication. Compared to the placebo and to comparator drugs, those taking semaglutide had substantially lower rates of non-fatal MI (myocardial infarction, or heart attack), non-fatal stroke, revascularization (needed surgery for bypass or other heart vascular issue) or hospitalization for an unstable angina (poor blood flow to heart). 

Data also showed, however, that semaglutide slightly increased the risk of being hospitalized for heart failure and had about the same risk (as compared to a placebo) of a cardiac death. Deaths from all causes were about the same as with a placebo. Overall, the drops were significant and the increases small.

Of concern was that diabetic retinitis showed a definite increase among users of semaglutide compared to the placebo. For a more detailed explanation, see: Weight Loss Wegovy Could Offer More Risks Than Benefits. 

In November 2023, Novo Nordisk published results of a much larger trial (including over 17,000 participants) testing Wegovy on patients with excess weight and diagnosed heart disease, but who did not have diabetes. They found that the drug lowered the risk of cardiovascular events such as heart attacks, stroke, and deaths over the course of about five years. It’s important to note that the trial did not specify lifestyle changes such as diet or exercise for participants who took Wegovy or who took a placebo. About a third of patients in both the Wegovy group and the placebo group reported experiencing severe adverse events (mostly gastrointestinal side effects or gallbladder disorders), but only 8.2% of those in the placebo group dropped out of the trial because of them, compared to 16.2% of those who were taking Wegovy.

Before Trying Wegovy

Jay was generally optimistic about the potential for Wegovy and similar drugs to help both adults and adolescents lose weight, but she emphasized that “the first step is not medications.” People looking to lose weight should start with lifestyle modifications such as increased physical activity and dietary interventions.

MedShadow offers several resources for those looking for guidance:

• Mediterranean Diet guide
• Strength Training for Beginners
• Outdoor Workouts When You Don’t Feel Like Running

If you’re not seeing weight loss trying these interventions alone, then you might consider enrolling in a comprehensive behavioral program. The National Institutes of Health (NIH) offers tips for finding a program that’s right for you. Make sure the program is designed to lead to slow and steady weight loss (no more than one to two pounds per week), and isn’t using extremely restrictive diets to promise quick, short-term solutions. The program should help establish a lifestyle change over the course of six months or more, that you or your teenager can stick with for life.

Finally, you might consider combining an intensive program with drugs like Wegovy, recognizing your weight loss might be temporary. As always, you should speak to your doctor to find the best route for you and make sure to ask about the side effects of Wegovy and Ozempic.