What are the Side Effects of GLP-1 Ozempic Wegovy Tirzepatide Zepbound

December 02, 2025

Glucagon-like peptide-1 (GLP-1) receptor agonists—including popular brand names like Ozempic (semaglutide), Wegovy (semaglutide), and Mounjaro (tirzepatide)—represent a revolutionary approach to managing type 2 diabetes and promoting significant weight loss. These medications work by mimicking natural gut hormones, which slows digestion, increases feelings of fullness, and helps regulate blood sugar.

While highly effective, these powerful drugs come with a range of potential side effects, primarily affecting the digestive system. Most side effects are mild and temporary, improving as your body adjusts to the medication. Understanding what to expect and how to manage these side effects is crucial for a successful and comfortable treatment journey.

The Most Common Side Effects (Gastrointestinal Issues)

The vast majority of side effects associated with GLP-1 medications are gastrointestinal (GI) in nature. These symptoms are most pronounced when you first start the medication or when your dose is increased, and they typically subside over time.

Nausea and Vomiting

Nausea is the single most common side effect, affecting up to 50% of patients. It occurs because the medication slows gastric emptying (how quickly food leaves the stomach), which can lead to a feeling of over-fullness or discomfort.

Management Strategies:

Eat Small, Frequent Meals: Opt for smaller portions spread throughout the day instead of two or three large meals.
Avoid Trigger Foods: Steer clear of high-fat, greasy, spicy, and overly sweet foods, which are harder to digest and can worsen nausea.
Eat Slowly and Stay Upright: Chew food thoroughly, eat slowly, and remain seated or standing for at least 30 minutes after eating to aid digestion via gravity.
Natural Remedies: Sipping on ginger or peppermint tea or eating ginger chews can help settle your stomach.

Constipation and Diarrhea

GLP-1s can disrupt normal bowel habits in both directions. Constipation is a frequent issue due to slowed digestion, while diarrhea can also occur as the gut adjusts.

Management Strategies:

Stay Hydrated: Drink plenty of water throughout the day (aim for at least 64 ounces daily) to prevent dehydration, which is key for both diarrhea management and preventing constipation.
Increase Fiber Gradually: Add fiber-rich foods like fruits, vegetables, beans, and whole grains to your diet. Increase intake slowly to avoid additional bloating or gas.
Stay Active: Regular physical activity, such as a daily walk, helps stimulate the colon and promotes healthy digestion.
OTC Relief: If symptoms persist, your doctor may recommend over-the-counter stool softeners for constipation or anti-diarrheal medication like loperamide.

Other Common GI Symptoms

Other frequent issues include abdominal pain, bloating, gas, heartburn, and indigestion. These are also related to slowed digestion and usually improve with dietary modifications and time.

Less Common but Manageable Side Effects

Beyond the digestive tract, some patients report other, less frequent side effects.

Fatigue and Headache: These can often be linked to reduced calorie intake or dehydration. Ensuring adequate nutrition, hydration, and sleep can help manage these symptoms.
Injection Site Reactions: Mild redness, swelling, or itching where the injection was administered is possible. Rotate your injection sites (abdomen, thigh, or upper arm) each week to minimize irritation.
Hair Loss: This side effect is usually temporary and often related to rapid weight loss, not the medication itself. Ensuring a nutrient-dense diet with sufficient protein can support hair health.
"Ozempic Face": This cosmetic change refers to a hollowed or sagging facial appearance due to rapid fat loss in the face. It can be managed by ensuring a gradual weight loss pace in consultation with your doctor.

Rare but Serious Side Effects (When to Call Your Doctor)

While most side effects are mild, it is important to be aware of the rare, serious complications that require immediate medical attention.

Pancreatitis

Inflammation of the pancreas is an uncommon but serious risk.

Symptoms: Stop taking the medication and seek immediate medical help if you develop severe, persistent abdominal pain that may radiate to your back, with or without vomiting.

Gallbladder Problems

GLP-1 medications can increase the risk of gallstones or gallbladder inflammation (cholecystitis).

Symptoms: Watch for severe upper stomach pain, fever, yellowing of the skin or eyes (jaundice), or clay-colored stools.

Kidney Damage

Acute kidney injury is rare but has been reported, often linked to severe dehydration caused by persistent vomiting and diarrhea.

Symptoms: Look for a reduced need to urinate, swelling in your legs or ankles, or unusual fatigue. Staying well hydrated is your best prevention strategy.

Thyroid C-Cell Tumors

Both semaglutide and tirzepatide carry a Boxed Warning (the FDA's strictest warning) about the potential risk of thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), based on animal studies. This risk has not been confirmed in humans, but you should not use these medications if you or a family member have a history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).

Symptoms: Immediately report a lump or swelling in your neck, a hoarse voice, or difficulty swallowing or breathing.

Other Serious Concerns

Bowel Obstruction/Ileus: A blockage in the intestines is a rare, but serious, potential side effect.
Severe Allergic Reaction: Seek immediate medical care if you experience symptoms like swelling of the face, tongue, or throat, hives, or trouble breathing.
Suicidal Thoughts: While a causal link has not been definitively established, patients should be monitored for new or worsening depression, unusual mood changes, or suicidal thoughts.

Working with Your Healthcare Provider

The best way to navigate potential side effects is through close collaboration with your medical team.

Start "Low and Slow": Your doctor will likely start you on the lowest dose and gradually increase it over several weeks. This titration process allows your body to adjust to the medication, significantly lowering the side effect profile.
Keep a Symptom Journal: Log your symptoms and food intake to help you and your doctor identify patterns and make necessary adjustments to your diet, dosage, or lifestyle habits.
Open Communication: Do not hesitate to contact your provider if side effects are persistent, severe, or interfere with your daily life. They can adjust your treatment plan or recommend specific anti-nausea or anti-constipation medications.

By being informed and proactive, you can effectively manage side effects and reap the significant health benefits of GLP-1 therapies in your weight loss journey.