Tirzepatide vs Semaglutide: Price, Weight Loss & Side Effects Compared

Two Leading GLP-1 Medications Compared

Semaglutide and tirzepatide are the two most prominent injectable weight loss medications available today. Both belong to the GLP-1 receptor agonist class, both are administered as weekly injections, and both have demonstrated significant weight loss in clinical trials. However, they differ in their mechanism of action, clinical results, pricing, and availability. This guide compares the two side by side to help you and your healthcare provider make an informed choice.

How They Work

Semaglutide is a GLP-1 receptor agonist, meaning it mimics the natural GLP-1 hormone that helps regulate appetite and blood sugar. It is the active ingredient in brand-name medications Wegovy (approved for weight management) and Ozempic (approved for type 2 diabetes). Tirzepatide is a dual GIP/GLP-1 receptor agonist, meaning it activates two incretin hormone receptors instead of one. This dual mechanism may provide additional metabolic benefits. Tirzepatide is the active ingredient in Zepbound (approved for weight management) and Mounjaro (approved for type 2 diabetes).

Weight Loss Results from Clinical Trials

In the STEP 1 trial of FDA-approved Wegovy (semaglutide 2.4 mg), participants lost an average of approximately 15% of their body weight over 68 weeks compared to 2.4% in the placebo group (Wilding et al., NEJM 2021). In the SURMOUNT-1 trial of FDA-approved Zepbound (tirzepatide), participants on the highest dose lost an average of approximately 22.5% of their body weight over 72 weeks compared to 2.4% in the placebo group (Jastreboff et al., NEJM 2022). These results are from studies of FDA-approved branded medications conducted in controlled clinical settings. Individual results may vary based on factors such as starting weight, diet, exercise, and adherence to treatment.

Side Effects

Both medications share a similar gastrointestinal side effect profile, which is common among GLP-1 receptor agonists. The most frequently reported effects include nausea, vomiting, diarrhea, constipation, and decreased appetite. These side effects tend to be most pronounced during the initial dose-escalation period and often diminish over time. Some clinical data suggests that tirzepatide may have slightly higher rates of certain gastrointestinal side effects at the highest doses, though both medications are generally well tolerated when doses are escalated gradually. Serious side effects are uncommon but may include pancreatitis, gallbladder problems, and allergic reactions. Both medications carry a boxed warning about the risk of thyroid C-cell tumors observed in animal studies.

Cost Comparison

Without insurance, brand-name Wegovy (semaglutide) typically costs between $1,300 and $1,600 per month at retail pharmacies. Brand-name Zepbound (tirzepatide) is similarly priced, generally ranging from $1,000 to $1,500 per month. Compounded versions of both medications are available through various telehealth providers at significantly lower prices. Compounded semaglutide is widely available from providers like Ro, Hims, and TrimRX, typically ranging from $149 to $399 per month. Compounded tirzepatide is also available but may be priced slightly higher, often ranging from $299 to $599 per month depending on the provider and dosage.

Injection vs Tablet Options

Semaglutide is available in both injectable and oral formulations. The oral version (brand name Rybelsus) is FDA-approved for type 2 diabetes but not specifically for weight loss, though some providers may prescribe it off-label. Tirzepatide is currently available only as an injectable medication. Both injectable formulations are administered once weekly. For patients who prefer to avoid injections, oral semaglutide may be worth discussing with a healthcare provider, though the weight loss data for the oral formulation is based on different dosing than the injectable studies.

Which Should You Choose?

The choice between semaglutide and tirzepatide depends on several factors, including your health profile, budget, and treatment goals. Semaglutide may be a better starting point for patients who prefer a lower-cost compounded option, want the most extensively studied GLP-1 medication, or are interested in an oral alternative. Tirzepatide may be preferred by patients who want the potentially greater weight loss demonstrated in clinical trials, have type 2 diabetes and may benefit from the dual GIP/GLP-1 mechanism, or have not achieved their goals with semaglutide alone. Ultimately, this is a decision best made in consultation with a licensed healthcare provider who can evaluate your individual circumstances.