What Are Wegovy and Zepbound?
Wegovy (semaglutide) and Zepbound (tirzepatide) are once-weekly injectable medications approved by the FDA for chronic weight management in adults with obesity or those who are overweight with at least one weight-related condition. These incretin mimetics mimic natural hormones to regulate appetite and are used alongside diet and exercise for weight loss.
Mechanism of Action: The Key Difference
Wegovy acts as a single GLP-1 receptor agonist, slowing gastric emptying and regulating blood sugar. Zepbound is a dual GIP and GLP-1 receptor agonist, providing more potent effects on appetite and metabolism due to its combined action.
Effectiveness in Clinical Trials
The SURMOUNT-5 trial, the first head-to-head comparison, showed Zepbound was more effective for weight loss than Wegovy. After 72 weeks, Zepbound patients lost an average of 20.2% of body weight, versus 13.7% for Wegovy patients. More Zepbound patients also achieved $\ge$ 15% and $\ge$ 20% weight loss compared to Wegovy patients.
Comparison Table: Wegovy vs. Zepbound
| Feature | Wegovy (Semaglutide) | Zepbound (Tirzepatide) |
|---|---|---|
| Active Ingredient | Semaglutide | Tirzepatide |
| Mechanism of Action | Single GLP-1 receptor agonist | Dual GLP-1 and GIP receptor agonist |
| Average Weight Loss | ~13.7% of body weight (72-week trial) | ~20.2% of body weight (72-week trial) |
| Pediatric Approval | Yes, for ages 12 and older | No, currently approved for adults only |
| Additional FDA Indications | Cardiovascular risk reduction in adults with heart disease | Obstructive sleep apnea in adults with obesity |
| Common Side Effects | Nausea, diarrhea, vomiting, stomach pain, headache, fatigue | Nausea, diarrhea, vomiting, constipation, abdominal pain, indigestion, fatigue |
| Side Effect Intensity | Generally considered well-tolerated, but still common | Can cause more intense GI side effects, especially during dose increases |
| Cost (without insurance) | Can range from $1,300 to $1,500 monthly | Can range from $1,000 to $1,200 monthly |
Side Effects and Tolerability
Both medications commonly cause gastrointestinal side effects like nausea and vomiting, especially during dose escalation. Tolerability varies among individuals, and some may find one drug more manageable than the other. Both carry a boxed warning for the risk of thyroid tumors based on animal studies.
Additional Approved Uses
Wegovy is approved for cardiovascular risk reduction in adults with heart disease. Zepbound is approved for moderate-to-severe obstructive sleep apnea in adults with obesity.
Which Medication is Right for You?
Choosing between Wegovy and Zepbound requires consulting a healthcare provider to consider individual factors beyond weight loss. These include weight loss goals, co-existing conditions like heart disease or sleep apnea, individual tolerability of side effects, age (Wegovy is approved for adolescents 12+), and insurance coverage/cost.
Conclusion
Zepbound generally leads to greater average weight loss due to its dual mechanism. However, Wegovy is a valuable option with an established track record, cardiovascular risk reduction indication, and approval for adolescents. The most effective treatment is a personalized decision made with a healthcare provider, considering all individual health factors and goals.
Frequently Asked Questions
Which medication leads to more weight loss, Zepbound or Wegovy?
Based on a head-to-head clinical trial, Zepbound (tirzepatide) led to a significantly greater average weight loss (20.2%) compared to Wegovy (semaglutide) (13.7%) over 72 weeks.
How are Zepbound and Wegovy different in their mechanism of action?
Wegovy acts as a single agonist for the GLP-1 hormone receptor, which helps regulate appetite. Zepbound is a dual agonist for both the GLP-1 and GIP hormone receptors, providing additional effects on metabolism and appetite suppression.
Do Zepbound and Wegovy have similar side effects?
Yes, both medications have similar common side effects, primarily gastrointestinal issues like nausea, diarrhea, and vomiting. However, the intensity of these effects can differ between individuals, and some evidence suggests Zepbound's dual mechanism may cause more intense GI effects.
Is one medication safer than the other?
Both medications carry similar serious side effect warnings, including a boxed warning for the risk of thyroid tumors based on animal studies. The overall safety profile and side effect tolerability are assessed individually with a doctor.
Is Wegovy or Zepbound available for adolescents?
Wegovy is FDA-approved for use in adolescents ages 12 and older with obesity. Zepbound is currently only approved for adults.
What if I have heart disease? Should I choose Wegovy?
If you have established cardiovascular disease, Wegovy is approved for cardiovascular risk reduction in addition to weight management, making it a potentially beneficial option for you. Your doctor will weigh this factor along with others during your consultation.
What about obstructive sleep apnea? Which medication helps with that?
Zepbound received FDA approval for the treatment of moderate-to-severe obstructive sleep apnea (OSA) in adults with obesity in December 2024, making it a relevant option for patients with this condition.
Does insurance cover Wegovy or Zepbound?
Insurance coverage varies widely depending on your specific plan. Prior authorization is often required, and out-of-pocket costs can be substantial without coverage.
Can you switch from Wegovy to Zepbound?
It is possible to switch between the medications under the guidance of a healthcare provider. A switch might be considered if you have plateaued on one medication or have experienced tolerability issues.
Which medication is less expensive?
Without insurance, Zepbound tends to be slightly less expensive than Wegovy, but manufacturer discounts or insurance coverage can significantly impact the final cost.
Does everyone experience the same results?
No. While clinical trials show average results, individual patient response can vary. Factors like genetics, diet, exercise, and metabolism all play a role in the outcome.
Key Takeaways
- Mechanism of Action: Zepbound's dual GLP-1/GIP action provides a more potent therapeutic effect than Wegovy's single GLP-1 action.
- Efficacy: A head-to-head trial demonstrated that Zepbound resulted in significantly greater average weight loss than Wegovy.
- Side Effects: Both medications cause similar GI side effects, though individual tolerability varies, and Zepbound's dual action may lead to more intense effects.
- FDA Approvals: Zepbound is approved for obstructive sleep apnea in adults, while Wegovy is approved for cardiovascular risk reduction in adults and weight management in adolescents.
- Informed Decision: The best choice for treatment depends on an individual's specific health profile, co-existing conditions, and overall treatment goals, determined in consultation with a healthcare provider.
