Zepbound vs Wegovy: Side effects, risks, and safety

In this article:

• Common side effects
• Serious side effects
• When do side effects start?
• How long do side effects last?
• Zepbound and Wegovy interactions
• How to avoid side effects?
• How to treat side effects?

In this article

• Common side effects
• Serious side effects
• When do side effects start?
• How long do side effects last?
• Zepbound and Wegovy interactions
• How to avoid side effects?
• How to treat side effects?

Zepbound (tirzepatide) is a weight loss medication approved for use in adults 18 years and older with obesity, and for treating moderate-to-severe obstructive sleep apnea. Wegovy (semaglutide) is another prescription medicine that is FDA-approved for weight reduction in adults and adolescents 12 years and older with obesity. 

Common side effects of Zepbound and Wegovy

Like most drugs, Zepbound and Wegovy may cause side effects. It is important to know these side effects and when to report them to your healthcare provider. 

Common Zepbound side effects

The most common side effects of Zepound include nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, and reflux reported in over 5% of patients treated with the drug in clinical studies.

Other common side effects include:

• Injection site reactions
• Tiredness 
• Hair loss
• Hypersensitivity reactions

Common Wegovy side effects

According to a clinical trial for Wegovy, the most common side effects were mild to moderate gastrointestinal problems. The most frequently reported gastrointestinal adverse effects were nausea, diarrhea, vomiting, and constipation.

Other common side effects of Wegovy include:

• Headache
• Tiredness 
• Upset stomach
• Dizziness
• Heartburn
• Runny nose or sore throat
• Back pain or abdominal pain 

Serious side effects of Zepbound vs. Wegovy

In rare cases, Zepbound and Wegovy may cause serious side effects, and they are noted below.

Serious Zepbound side effects include:

• Thyroid tumors 
• Severe gastrointestinal issues 
• Acute kidney injury
• Acute gallbladder disease
• Diabetic retinopathy (damaged blood vessels in the eye in Type 2 diabetes)
• Pancreatitis (inflammation of the pancreas) 
• Severe allergic reactions may include a rapid heartbeat, breathing difficulties, a swollen face, lips, or tongue, and problems swallowing. 
• Hypoglycemia (low blood sugar, in Type 2 diabetes) 
• Vision changes in Type 2 diabetes 
• Worsening of depression or suicidal thoughts

Serious Wegovy side effects include

• Thyroid tumors
• Pancreatitis 
• Gallstones and gallbladder disease 
• Acute kidney injury 
• Serious gastrointestinal problems
• Hypoglycemia in people with Type 2 diabetes
• Serious allergic reactions like swelling of the face, tongue, or throat, difficulty swallowing, or breathing. 
• Vision problems in people with Type 2 diabetes 
• Worsening of depression or suicidal thoughts

How soon do side effects start for Zepbound and Wegovy?

Zepbound

Typically, Zepbound side effects may start within the first few days of taking the shot. However, it is not a one-size-fits-all solution, as it varies depending on the individual and the dosage.

Wegovy

Patients may start experiencing Wegovy side effects within the first week, and these side effects often decrease over time as the body adjusts. 

How long do Zepbound and Wegovy side effects last?

Side effects, such as nausea and constipation, may be temporary and last two to four weeks as your body adjusts. However, the duration of side effects for Zepbound and Wegovy varies per individual.

Zepbound

“How long a patient takes to adapt to the side effects of the medications varies considerably. Nausea is the most common side effect and resolves on its own,” says Mir Ali, MD, board-certified general surgeon, bariatric surgeon, and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA. “Some patients require anti-nausea medication for short-term use. Interestingly, Zepbound, which works on two receptors, seems to have fewer side effects. Nevertheless, the side effects tend to subside as the dose of the medication is adjusted every four weeks. It is very uncommon that a patient stops either medication due to side effects.”

Wegovy 

“I advise patients that it’s difficult to predict how quickly they will adjust to Wegovy,” says Jennifer Brown, MD, board-certified obesity medicine doctor with MyObesityTeam. “Most patients adjust to the side effects within a few weeks, but others take longer. Some patients experience no side effects (or fewer side effects). The negative side effects of GLP-1s vary from patient to patient. I do find that patients are more likely to tolerate Zepbound than Wegovy.”

What are the long-term side effects of Zepbound and Wegovy?

The side effects of Zepbound and Wegovy are often short-term and lessen as your body adjusts to the medication. However, discuss potential long-term side effects with your healthcare provider to make an informed decision if you plan to use them for long-term weight management. 

Zepbound

“Zepbound has been on the market for only three years, but its possible long-term side effects are likely to be similar to those of other GLP-1s,” Dr. Brown says.“When I start patients on Zepbound, we discuss the potential concerns of thyroid cancer, pancreatitis, gallbladder disease, or kidney problems. These long-term problems are rare.” 

Wegovy

According to an article by Johns Hopkins University, researchers have yet to fully understand the long-term effects of GLP-1 medications, including Wegovy. In one clinical trial that spanned four years (the first long-term study on Wegovy), 17% of over 17,000 participants discontinued Wegovy due to gastrointestinal side effects, such as nausea (most common). Additionally, GLP-1 medications, including Wegovy, may be associated with a slightly increased risk of thyroid cancers, and the risk increases the longer you are on the medication. 

Zepbound and Wegovy interactions

Similar to most drugs, Zepbound and Wegovy interact with other medications. Discuss all the medications and supplements you are taking with your healthcare provider. They can guide you on how to use them safely.

Zepbound interactions

• Sulfonylureas and Meglinitides: If you are on Zepbound and have Type 2 diabetes, your healthcare provider may need to adjust the dosage of sulfonylureas and meglitinides to reduce the risk of hypoglycemia.
• Insulin: The combination of insulin and Zepbound may interact to lower blood sugar levels. It’s essential to work with your healthcare provider while using insulin and Zepbound to avoid dangerously low sugar levels.
• Other glucose-dependent insulinotropic polypeptide (GLP-1) receptor agonists: Do not combine Zepbound with products containing the active ingredient tirzepatide (like Monjauro ), or other GLP-1 receptor agonists. 
• Oral contraceptives: Zepbound affects the absorption of oral contraceptives (birth control pills). The best option, as advised by the manufacturer, is to use a non-oral contraceptive method while on Zepbound or use a barrier method of contraception in the first four weeks of starting the medication and for 4 weeks after every dose increment.

Wegovy interactions

• Insulin: The combination of insulin and Wegovy needs close supervision from your healthcare provider due to the increased risk of hypoglycemia.
• Sulfonylureas or meglitinides: If you are taking drugs belonging to these classes, sulfonylureas or meglitinides, you need to be monitored to prevent hypoglycemia.
• Other GLP-1 agonists: Avoid using Wegovy with semaglutide-containing products like Ozempic and Rybelsus, or other GLP-1 agonists (for example, Byetta, Trulicity).
• Oral medications: If you are on oral medications like the blood thinner warfarin, the anticonvulsant phenytoin, and the thyroid replacement medication levothyroxine, inform your healthcare provider. Wegovy may delay the absorption of these oral medications.

Safety measures while using Zepbound and Wegovy

Here are precautions to help use Zepbound and Wegovy safely: 

• Family history of thyroid cancer: Zepbound and Wegovy come with boxed warnings of increased risk of thyroid cancers. “A patient with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome should not take Zepbound and Wegovy. They are contraindicated,” Dr. Brown says. 
• Age limitations: Wegovy is not recommended for children under 12 years old. Zepbound is not approved for people under 18 years old. 
• Severe gastrointestinal problems: “I try to avoid GLP-1s, including Zepbound and Wegovy, if a patient has chronic pancreatitis or severe gastroparesis—slow gastric emptying usually caused by diabetes,” Dr. Brown says.
• Type 2 diabetes: People with Type 2 diabetes need ongoing support while on Zepbound and Wegovy. “I monitor patients with diabetes on insulin; adding a GLP-1 medication could make them severely hypoglycemic,” Dr. Brown says.
• Pregnancy: It’s advised to discontinue Wegovy and Zepbound two months before conception and not to use them in pregnancy.
• Breastfeeding: Do not use Wegovy and Zepbound if breastfeeding. It is unknown whether the medication can be passed through breast milk.
• Other health conditions: Discuss your medical history with your healthcare provider. Particularly, let them know if you have kidney problems, pancreatitis, type 2 diabetes, a history of retinopathy, or mental health issues (depression or suicidal thoughts) for proper monitoring. These medications are not recommended for people who have had suicide attempts or active suicidal thoughts.
• Surgery: Notify your healthcare provider if you are scheduled for surgery or procedures that require sedation. Wegovy and Zepbound increase the risk of food and liquid getting into your airways during such procedures.
• Overdose: The recommended maintenance dose for Zepbound is 5 mg, 10 mg, or 15 mg for weight loss (once-weekly injection), starting with a lower dose of 2.5 mg and increasing to a higher dose after four weeks. For Wegovy, the maintenance dose is 1.7 mg or 2.4 mg, with a starting dose of 0.25 mg, administered once weekly, followed by a gradual increase to a higher dose based on your treatment plan. Symptoms of an overdose include severe nausea, vomiting, or very low blood sugar. The best thing to do when an overdose is suspected is to seek emergency medical attention and call the poison help line (1-800-222-1222).

How to avoid side effects for Zepbound and Wegovy

Dr. Brown says her standard advice to patients starting on Wegovy or Zepbound includes:

1. Stay well-hydrated.
2. Eat small meals, and stop eating when full.
3. Consume at least 70 grams of protein a day.
4. Incorporate healthy lifestyle changes, like strength training at least two days a week. 

“These tips go a long way towards minimizing side effects. If a patient has significant side effects despite following this advice, I’ll consider lowering their dose temporarily,” Dr. Brown explains. “Some patients never adjust to the side effects of Wegovy and Zepbound, and are not able to take it at any dose.”

Additionally, learn the proper administration technique (subcutaneous injection in the abdomen, thigh, or upper arm) and always rotate injection sites to avoid skin reactions. Finally, read the drug information, and direct questions to your healthcare provider if anything is unclear. 

How to treat side effects of Zepbound and Wegovy

“I advise patients that if they are experiencing any side effects or are not sure if certain effects are due to the medication, they should call me immediately. Usually, the symptoms can be managed. However, if a patient experiences severe symptoms (nausea that is not improving with medications, inability to tolerate liquids, or other issues), then they should seek attention in urgent care or the emergency room,” Dr. Ali says.