Nearly half of all Wegovy users experience nausea, making it the most common side effect, and gastrointestinal symptoms in general are the top reason people consider stopping treatment. The good news is that most of these side effects are manageable with straightforward dietary and lifestyle adjustments, and they tend to improve as your body adapts to each dose level.
What to Expect: The Most Common Side Effects
In clinical trials of more than 2,100 adults taking the full 2.4 mg dose, gastrointestinal symptoms dominated the side effect profile. Nausea affected 44% of users (compared to 16% on placebo), diarrhea hit 30%, vomiting and constipation each affected 24%, and abdominal pain showed up in 20%. Beyond the gut, about 11% of users reported fatigue, and 3% noticed hair thinning.
These numbers represent the full trial period, including the dose escalation phase when side effects peak. Wegovy’s built-in titration schedule exists specifically to ease your body into the medication. You start at 0.25 mg weekly for the first four weeks, then step up to 0.5 mg, 1 mg, and 1.7 mg in four-week intervals before reaching the maintenance dose of 2.4 mg around week 17. Most people find that nausea and other GI symptoms are worst during the first few weeks at each new dose, then gradually settle.
Reducing Nausea and Vomiting
Nausea is the side effect that derails people most often, but how you eat matters almost as much as what you eat. Wegovy works partly by slowing how fast your stomach empties, which means large meals sit longer and trigger more discomfort. Switching to smaller, more frequent meals reduces the volume your stomach has to process at any given time and helps keep blood sugar stable, which itself prevents nausea from blood sugar dips.
Avoid high-fat foods, fried foods, and anything heavy in added sugar. These are the hardest for your body to digest and the most likely to cause nausea while on a GLP-1 medication. Fast food is a common offender. Eating too close to bedtime also worsens symptoms because lying down with a full, slow-emptying stomach pushes food and acid upward.
Staying well hydrated is critical. Wegovy increases your risk of dehydration, especially if you’re already losing fluids through vomiting or diarrhea. Dehydration itself worsens nausea, creating a cycle that’s easy to fall into. Sip water throughout the day rather than drinking large amounts at once, and consider beverages with electrolytes if you’re struggling to keep food down.
Dealing With Constipation and Diarrhea
It might seem contradictory that Wegovy causes both constipation and diarrhea, but different people respond differently to slowed digestion. For constipation, increasing your water intake is the simplest first step, since the slower transit time means your intestines absorb more water from stool. Adding fiber-rich foods like vegetables, whole grains, and fruits can help keep things moving, though it’s best to increase fiber gradually to avoid making bloating worse.
For diarrhea, hydration is equally important because you’re losing fluids faster than normal. Bland, easy-to-digest foods like rice, bananas, and toast can help firm things up while your gut adjusts. If diarrhea is persistent, an over-the-counter option like loperamide can offer short-term relief, but pay attention to whether episodes cluster around dose increases. They often resolve on their own within a couple of weeks at each dose level.
Managing Heartburn and Acid Reflux
Delayed stomach emptying doesn’t just cause nausea. It also increases the chance of acid reflux, especially at night. Over-the-counter antacids or alginates like Gaviscon can provide quick relief, while acid-reducing medications like famotidine work better for ongoing prevention by lowering the amount of acid your stomach produces in the first place.
If nighttime heartburn is a problem, elevate the head of your bed by about six inches. This slight incline makes it harder for stomach acid to travel up into your esophagus while you sleep. Avoiding food for at least two to three hours before lying down also makes a noticeable difference, since your stomach is emptying more slowly than it did before you started the medication.
Fighting Fatigue Without Undermining Weight Loss
Fatigue on Wegovy usually comes down to one thing: you’re not eating enough. The appetite suppression can be dramatic, and many people unintentionally drop their calorie intake to levels that leave the body running on fumes. Eating fewer than about 1,200 calories a day for women or 1,500 for men can push your body into a state of exhaustion. Tracking your intake for a few days, even roughly, can reveal whether under-eating is the culprit.
When your appetite is low, every bite counts. Prioritize lean protein sources like chicken, fish, tofu, or Greek yogurt. Protein helps preserve muscle mass during weight loss, which is essential for maintaining your metabolism and preventing the sluggish feeling that comes with muscle wasting. Hydrating with electrolytes also helps, since even mild dehydration from GI side effects can sap your energy.
Vitamin B12 is worth paying attention to as well. Your body needs B12 to produce energy, and because Wegovy changes how you digest and absorb food, you may not be getting enough. Low B12 can compound the fatigue you’re already feeling from reduced calorie intake. A simple blood test can check your levels.
Protecting Against Muscle Loss
Weight loss from any method involves some muscle loss alongside fat, but research presented by the Endocrine Society found that certain groups are more vulnerable on semaglutide. Older adults, women, and people eating less protein all showed greater muscle loss during treatment. Eating more protein appeared to protect against this, though researchers are still working to pin down the optimal amount.
Resistance training is the other half of the equation. Strength exercises like bodyweight squats, resistance bands, or weight lifting signal your body to hold onto muscle even while you’re in a calorie deficit. You don’t need an intense gym routine. Two to three sessions a week focusing on major muscle groups can make a meaningful difference in body composition during treatment.
Minimizing Hair Thinning
About 3% of adults in Wegovy trials experienced hair loss, compared to 1% on placebo. This isn’t a direct drug effect but rather a condition called telogen effluvium, where the metabolic stress of rapid weight loss pushes a larger-than-normal percentage of hair follicles (anywhere from 7% to 35%) into their resting and shedding phase at the same time.
The key trigger is losing weight too fast. Ensuring you’re eating enough calories and getting adequate protein and nutrients can slow the rate of loss and reduce the stress signal that triggers shedding. Telogen effluvium is typically temporary. Once your weight stabilizes and your body adjusts, hair growth cycles usually return to normal over several months.
Reducing Injection Site Discomfort
Rotate your injection site each week between your stomach, thigh, or the back of your upper arm (if someone else is injecting for you). Using the same spot repeatedly increases the chance of soreness, bruising, or skin irritation. Applying a cold compress before the injection can numb the area, or you can use one afterward to reduce inflammation. Always use a clean injection site and a new needle for each dose.
Warning Signs That Need Attention
Most Wegovy side effects are uncomfortable but harmless. A few, however, signal something more serious. Watch for severe, constant abdominal pain that doesn’t come and go like typical GI discomfort, particularly pain in the upper right area of your abdomen, which could indicate gallbladder problems. Consistently pale stools suggest a lack of bile secretion and warrant investigation. Intractable nausea that doesn’t respond to any of the strategies above, especially with vomiting that prevents you from keeping fluids down, is another red flag.
Very rapid weight loss, persistent loss of appetite beyond what feels like normal suppression, and significant muscle wasting can be early signs of pancreatic inflammation. These symptoms call for prompt medical evaluation rather than watchful waiting.