Ozempic and other drugs in the GLP-1 receptor agonist family have rapidly become famous for dramatic weight loss, but every few weeks it also seems we hear that social media users are shining a light on another new Ozempic side effect. These reactions include hair loss, fierce gastrointestinal distress, and rare (but severe) stomach paralysis. Some of these secondary effects have been scientifically verified, while others are still just anecdotal.
A brief note: This article uses the brand name Ozempic to refer to semaglutide, the drug’s active ingredient. Semaglutide is also marketed under two other names, Wegovy (when sold for weight loss) and Rybelsus (in the form of a pill rather than an injection). Other related drugs, such as liraglutide (Victoza) and tirzepatide (Mounjaro, Zepbound) may cause some of the same side effects.
These uncomfortable gastrointestinal troubles make up Ozempic’s most common and most discussed side effects by far.
While a majority of users don’t perceive these pains, a very substantial minority do. According to the U.S. Food and Drug Administration (FDA), placebo-controlled trials of Ozempic found the following rates of side effects from the 1 milligram (mg) dose.
All told, 30.8 percent of adults reported a gastrointestinal symptom. But that was only the 1 mg dose, half the maximum. The numbers were much higher in a trial of semaglutide (Wegovy) at 2.4 mg in people without diabetes.
At this, the highest dosage of semaglutide available, an incredible 74 percent of participants experienced at least one gastrointestinal disorder, though it’s worth noting that nearly 50 percent of those who took a placebo also had some tummy troubles.
For some, the gastrointestinal distress is just too much to handle, and they need to stop taking Ozempic entirely. As a blogger for New York magazine’s The Cut put it, “You might go through hell for your post-Ozempic body.” The author spoke to a 42-year-old woman with diabetes who endured “constant nausea” and “power-puking” for weeks, before finally weaning herself off the drug. In a pivotal trial, 4.5 percent of Wegovy patients stopped taking the medication as a direct result of gastrointestinal disorders — nearly 1 in every 20.
These unfortunate effects are strongest in the days immediately after injecting the once-weekly medication. Patients are also most likely to experience problems when they start on the drug or when they step up to a higher dosage; the side effects commonly fade away as the body gets used to the medicine.
Ozempic Burps
A foul-smelling burp isn’t exactly the most debilitating of side effects, but it can be rather unpleasant. As discussed in many YouTube and TikTok videos, some people taking Ozempic find themselves emitting nasty sulfurous smells when they belch. There is broad agreement that the burps smell like rotten eggs.
Only a minority of semaglutide trials have identified burping, or “eructation,” as a side effect. Anecdotal reports suggest that the burps, like other gastrointestinal issues, are worse when patients begin taking their drugs or step up to higher dosages.
Bloating and Farting
These uncomfortable side effects were reported in clinical trials as “abdominal distension” and “flatulence.” Bloating and farting complaints are less common than the gastrointestinal effects discussed above, and they have yet to catch on as hot topics on social media, but it’s good to know that Ozempic and related drugs may increase their likelihood.
GERD (Acid Reflux)
GLP-1 users have a somewhat increased risk of gastroesophageal reflux disease (GERD), a condition in which the stomach acid can flow backward, up into the esophagus. GERD is also known as acid reflux, and its symptoms are sometimes called heartburn or indigestion.
A study of more than 20,000 GLP-1 users found that they were about 27 percent more likely to develop the condition, and about 55 percent more likely to experience the complications of GERD, which can cause difficulty swallowing because of scarring and open sores in the esophagus.
While GLP-1 medications are best known for digestive problems, they also cause a handful of other side effects in a minority of users.
Tiredness and Fatigue
There are reports that Ozempic can cause fatigue — basically, tiredness or exhaustion that isn’t improved by sleep. The FDA label for semaglutide (Wegovy) reports that 11 percent of trial participants experienced fatigue, a little bit more than twice as often as those who used a placebo.
It’s unclear why Ozempic would cause fatigue, although one very plausible explanation is the fact that it causes people to eat so much less food. Ozempic causes extreme weight loss by encouraging users to eat at an extreme calorie deficit. You’re putting less fuel into your body, essentially crash dieting. Is it any wonder that Ozempic might sap your energy?
Dizziness
Dizziness has also been reported in a slim minority of Ozempic users, according to the drug's FDA label. It is possible that Ozempic dizziness stems from the glucose-lowering effects of the drug — dizziness is a common symptom of hypoglycemia. Even patients who are not at risk of severe hypoglycemia (typically those who do not use insulin or sulfonylureas) may feel dizzy while experiencing transient low blood sugar episodes.
Increased Heart Rate
There’s been relatively little online chatter about this side effect, which is noted on Ozempic’s FDA label. In clinical trials, lower doses of Ozempic “resulted in a mean increase in heart rate of two to three beats per minute.” Some patients have found the experience uncomfortable.
The FDA advises patients to “inform their healthcare providers of palpitations or feelings of a racing heartbeat while at rest.” Those who experience “sustained” increases in resting heart rate should discontinue the medication.
While this side effect seems disconcerting, it’s worth remembering that semaglutide and tirzepatide have overwhelmingly positive effects on heart health. Semaglutide was recently approved as a treatment for the prevention of heart attacks, and preliminary studies suggest that tirzepatide also imparts broad cardiovascular benefits.
“Ozempic face” may have been the first Ozempic side effect to go viral. Soon after, the pattern repeated itself when claims of “Ozempic butt” and “Ozempic breasts” hit headlines. In each case, users complained that the drug had given some part of their bodies a surprising and unfortunate flabby appearance.
There’s nothing to worry about. There is no evidence that Ozempic or any other similar drug directly affects your appearance. Experts seem to agree that Ozempic face, Ozempic breasts, and Ozempic butt are purely caused by weight loss. The same flabby results can and will occur when you lose weight the old-fashioned way, or through other medical methods such as bariatric surgery.
It turns out that not all weight loss enhances your appearance. When you lose a lot of weight, you might also lose some healthy-looking fat that you’d prefer to keep in places like your face or butt. Rapid weight loss can also lead to saggy skin: The skin is an adaptable and elastic organ, but it cannot snap instantly back into a taut shape. Successful dieters have struggled with these issues since long before Ozempic came on the scene.
Hair Loss
Ozempic can cause hair loss. While it isn’t listed as a side effect on Ozempic’s FDA label, hair loss is listed on the FDA's label for Wegovy, essentially the same medication. Three percent of participants in the drug’s pivotal trial reported hair loss (three times as many as those who used a placebo).
Like Ozempic face and Ozempic butt, however, this is merely a common consequence of rapid weight loss. Dramatic weight loss, no matter how it’s caused, often causes hair loss. This side effect is usually only temporary.
Muscle Loss
It is inevitable that weight loss will involve some muscle loss. This is considered healthy and natural.
Some experts, however, believe that Ozempic and related drugs are causing a surprising and worrying amount of muscle loss, and drugmakers are working hard to find new therapies that will help better preserve muscle.
The data tends to suggest that GLP-1 users lose about the same amount of muscle mass as people who lose weight through other means, but certain individuals may be at an enhanced risk of harmful muscle (and bone) loss due to their diet, physical activity habits, or health status. Experts agree that it would be wise for users to engage in strength-building exercises to help preserve muscle mass during weight loss. Eating enough protein may also help.
This potential side effect may also be a good reminder that Ozempic is inappropriate for people who do not have a good medical reason to lose weight.
GLP-1 drugs affect the brain as well as the digestive system.
Relief From Food Noise, the Desire to Drink, and Addictive Behaviors
Many Ozempic users are amazed to find that they are engaging in less addictive and compulsive behavior. Somehow the drug appears to reduce our damaging tendency to overindulge in activities like drinking, shopping, gambling, or even biting our nails.
The science here is still in its infancy, but it appears that one of the reasons Ozempic is able to stem hunger cues is by acting directly in the brain. We know that Ozempic doesn’t just help you feel full faster, it actually lowers your craving for food, switching off the food noise that compels some people to perpetually fixate on their next snack or meal. And it seems as if the drug reduces your craving for other things, too.
Experts have known for years that GLP-1 receptor agonists might have these behavioral effects. In a study of exenatide (Byetta), brain scans showed that the drug lowered activity in “crucial brain areas for drug reward and addiction.” It also calmed down the brain’s dopamine circuitry. Multiple clinical trials are now underway to explore the potential of GLP-1 drugs as anti-addiction medication.
We are years away from the day that Ozempic or any related drug could be prescribed as a therapy for addictive or compulsive behavior. But in the meantime, it could help users with more than just compulsive eating.
Suicidal Thoughts
Government health authorities in the United States and European Union initially signaled concern that semaglutide and other GLP-1 drugs were causing thoughts of suicide and self-harm.
A thorough review of the evidence, however, appears to have set those concerns to rest. Regulators in both the United States and Europe have announced that they could find no link.
Today, the official FDA labels for Wegovy and Zepbound continue to warn that there is a risk of suicidal ideation, but the agency clarified in its announcement that the warning is based on evidence from “older medicines used or tested for weight loss.”
Ozempic may cause dry mouth (xerostomia). Saliva helps to cleanse the mouth, and a lack of saliva can allow bacteria to fester, grow, and get stinky. Though dry mouth was not initially reported among semaglutide’s known side effects, it has been widely discussed in social media and clinicians have published reports of extreme cases.
“Keto breath” may also explain some cases of Ozempic breath. This side effect is common when people switch to a keto diet, which strictly limits the number of carbohydrates you are allowed to eat. Keto breath, which tends to have a fruity aroma, is caused by acetone, a by-product of ketosis. It is probable that some Ozempic users have unintentionally adopted a ketogenic eating pattern as a result of their diminished appetites — eating 50 grams (g) or less of carbohydrates per day can trigger ketosis.
Some users have also complained that their oral health has declined while using a GLP-1 drug, a phenomenon known as “Ozempic teeth.” The same lack of saliva that can cause bad breath may also lead to tooth decay and tooth sensitivity due to the higher rates of bacteria. The common side effect of vomiting may also play a role, as stomach acid can erode tooth enamel. Staying well-hydrated and practicing good oral hygiene may help prevent these complications.
Although it's rare, some people who use GLP-1 drugs experience changes to their vision.
Nonarteritic Anterior Ischemic Optic Neuropathy
Semaglutide could be causing a potentially blinding eye condition known as nonarteritic anterior ischemic optic neuropathy (NAION).
NAION occurs when the optic nerve head, where the retina and optic nerve connect, experiences constriction and swelling. Eventually, this can cause cell death in the retina due to insufficient blood flow, leading to vision loss. Usually only one eye is affected.
NAION develops quickly and without warning. Most people with NAION experience some loss of vision, but the condition does not typically get worse. Experts don’t understand exactly how NAION is caused, but known risk factors include type 2 diabetes, obesity, heart disease, hypertension, and sleep apnea — conditions that are common among semaglutide users. It is most common in people over age 50. There is no known treatment.
The American Academy of Ophthalmology notes that millions of people have taken semaglutide without developing NAION, and that at present there is no reason to stop using the medication. Anyone experiencing sudden loss of vision or significant vision changes should seek immediate medical help.
Diabetic Retinopathy
People with diabetes should know that there is some evidence that semaglutide may increase the incidence or progression of diabetic retinopathy, an eye disease that can lead to vision loss. At least one early study of the drug found an increased risk of the condition, but other studies have found no risk.
If the connection is real, it seems possible that semaglutide’s incredible effectiveness explains its negative effect on the eyes. Contrary to all expectations, rapid improvement in glucose control can actually worsen diabetic retinopathy. This is called early worsening, because the eyes will get worse before the major long-term benefits of better blood sugar control become evident.
Experts from the American Academy of Ophthalmology suggest that the progression of retinopathy caused by semaglutide is both temporary and manageable, although the organization does call for increased scrutiny from eye doctors.
GLP-1 drugs could double the incidence of neovascular age-related macular degeneration, also known as wet AMD, an eye disease that can sometimes lead to blindness. The longer people used their drug, the higher their risk grew. The overall risk, however, remains low: In a large study, 0.2 percent of the people taking a GLP-1 developed the condition, compared with 0.1 percent of the people who did not use a GLP-1 drug.
Age-related macular degeneration is characterized by a deterioration of the retina and choroid, the layer of blood vessels and other tissues that connect the retina to the white of the eye. It can lead to very blurry vision. In wet AMD, new abnormal blood vessels grow over the most important part of the retina, which leads to a loss of central vision. The condition is most common in people over age 55, and may begin with a dark spot in the center of your vision or extra difficulty seeing in dim lighting. Though wet AMD may be a rare consequence of GLP-1 usage, it is still important to see a doctor quickly if you experience significant vision changes, as early treatment is vital to stopping the progression of this disease.
GLP-1 medications can also cause changes that affect your sexual health and sex life.
Ozempic Babies
We may be experiencing an Ozempic baby boom. Across social media, women are crediting surprise pregnancies to their GLP-1 medication.
Though there’s no solid data on the phenomenon, experts agree that Ozempic has a number of different features that could account for increased fertility. Obesity itself has long been known to cause subfertility and infertility, so the dramatic weight loss associated with Ozempic could easily increase a woman’s chances of conceiving. The effect may be even stronger when weight loss and metabolic improvements help improve or alleviate a condition like polycystic ovary syndrome (PCOS).
There is also a chance, however, that GLP-1s could interfere with the birth control pill. Today, there is no scientific evidence that this happens, but a related drug in the class, tirzepatide (Mounjaro, Zepbound), carries warnings on its FDA labels that it “may reduce the efficacy of oral hormonal contraceptives due to delayed gastric emptying.” Patients are advised to switch to a non-oral form of contraception or to add a barrier method, such as condoms.
Erectile Dysfunction
Men without diabetes who use semaglutide could be far more likely to experience erectile dysfunction and hypogonadism (low testosterone). The data confirms anecdotal evidence on social media, where some men have complained that the drug has lowered their sex drive or made it more difficult to maintain an erection.
This result may be surprising, because weight loss usually improves erectile dysfunction. The science is still unclear, however, as other studies have found that GLP-1 medications can actually increase testosterone levels and improve erectile dysfunction.
Kidney Failure Research indicates that in some cases, use of semaglutide contributes to kidney disease. Dehydrating side effects, particularly diarrhea and vomiting, may enhance this risk. Nevertheless, for most people the drug appears to have a positive effect on kidney health.
Gallbladder Disease This may cause severe stomach pain, yellowing of the eyes or skin, fever, and clay-colored stools. Medication or surgery to break up gallstones may be necessary; in extreme cases, gallbladder removal surgery is an option.
Thyroid C-Cell Tumors Semaglutide’s FDA label warns of the risk of developing thyroid cancer, which has been observed in studies of rodents. A European health authority, however, announced that it couldn’t find any link in humans.
Pancreatitis This condition, in which the digestive enzymes attack the pancreas, may feel like intense stomach pain that radiates to your back. Most experts, however, are doubtful that semaglutide really increases the risk.
There have been some reports of allergic reactions to GLP-1 receptor agonists.
Stomach Paralysis (Gastroparesis)
Weight loss drugs such as Ozempic have been tied to a rare but increased risk of severe stomach problems. In July 2023, CNN reported that some semaglutide users had experienced gastroparesis, or stomach paralysis, which in some cases did not get better even months after discontinuing the medicine. Dozens of lawsuits have been filed against the manufacturers of GLP-1 medications alleging that the makers did not sufficiently warn users about the risk of severe side effects such as gastroparesis.
Gastroparesis is a condition in which the stomach empties too slowly or stops; it causes a variety of gastrointestinal symptoms, including bloating, abdominal pain, nausea, and vomiting. In the worst cases, gastroparesis can make it very difficult to eat or drink anything at all, potentially causing dehydration or malnutrition.
Delayed stomach emptying, the defining feature of gastroparesis, is a known consequence of Ozempic and related drugs. This delayed emptying partially accounts for some of Ozempic’s positive effects: reduced hunger and weight loss. It is also responsible for less severe side effects, such as gastrointestinal discomfort.
Luckily, severe and persistent gastroparesis appears to be very rare. The symptom was not identified in any of the drug's phase 3 trials, which enrolled thousands of participants to evaluate semaglutide's safety.
Temporary Intestinal Paralysis (Ileus)
Stomach paralysis isn’t the only severe gastrointestinal side effect that users have reported.
In late September 2023, the FDA updated the official Ozempic label to warn users of a potential risk of ileus, a type of intestinal blockage. Ileus occurs when the muscles that push food through the intestines are temporarily paralyzed, trapping food within the gut. The symptoms resemble those of a physical bowel obstruction, including bloating and constipation, and the condition can lead to dehydration.
Ileus is likely a rare side effect — it wasn’t identified in previous clinical trials, which evaluated semaglutide in thousands of participants. In its updated guidance, the FDA noted, “Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.”
Low Blood Sugar
While Ozempic probably does not itself cause low blood sugar (hypoglycemia), its glucose-lowering effect can sharply increase the odds that other drugs, principally insulin or sulfonylureas, cause hypoglycemia. If Ozempic lowers your baseline blood sugar level, your old dosage of glucose-lowering medication may now be more than you need.
If you have diabetes and you’re starting a new GLP-1, you may need to change the dosages of the other diabetes drugs that you use. Your doctor may also ask you to be extra vigilant about checking your blood sugar. If you’re not comfortable changing your insulin-dosing practices by yourself, you should be ready to contact your doctor between visits to get guidance on making adjustments.
Semaglutide and other GLP-1 drugs are associated with a wide variety of adverse events, most commonly gastrointestinal distress.
Other side effects, such as vision issues or stomach paralysis, can be extremely rare.
Some of the buzzier side effects, such as “Ozempic face” or “Ozempic butt,” are not caused by any interaction with the drug but instead are unintended weight loss consequences.
These drugs are powerful stuff: If you’re experiencing a reaction that you can’t explain, please reach out to your healthcare provider.
