Semaglutide and tirzepatide are the two most prescribed weight-loss medications in the U.S. Both are once-weekly injections that reduce appetite and help you feel full sooner. In the only head-to-head trial, people on tirzepatide lost more weight on average. But the right choice depends on your health history, how your body tolerates the medication, and your goals.
Plain English
How Each One Works.
Semaglutide
Mimics one gut hormone (GLP-1). The molecule in Wegovy (weight) and Ozempic (diabetes), with the longer research record.
Tirzepatide
Mimics two gut hormones (GLP-1 and GIP). The molecule in Zepbound (weight) and Mounjaro (diabetes).
Both slow how fast your stomach empties and quiet the “food noise” many people describe. Tirzepatide acts on a second hormone, GIP, which researchers believe adds to its effect.
The Research
What the Head-to-Head Trial Found.
In SURMOUNT-5, the first head-to-head trial, adults with obesity took either tirzepatide or semaglutide for 72 weeks.
Source: SURMOUNT-5, New England Journal of Medicine, 2025. Trial averages; individual results vary and depend on sustained use.
Averages don’t tell the whole story. Some people lose more on semaglutide than others do on tirzepatide. Results also depend on reaching the right dose, eating enough protein and staying active.
Side Effects
What to Expect.
The most common side effects are similar for both. They’re usually stomach-related and strongest when your dose goes up:
- Nausea
- Diarrhea or constipation
- Vomiting
- Feeling full quickly or losing interest in food
Most people find these ease within a few weeks. Raising the dose slowly, eating smaller meals and staying hydrated help.
Less common but serious risks include pancreatitis and gallbladder problems. Neither medication is right for people with a personal or family history of medullary thyroid cancer or MEN2, or for anyone pregnant or trying to get pregnant.
Brand-name vs. compounded
A compounded medication is prepared by a state-licensed pharmacy for one named patient, from a provider’s prescription. Ingredients come from FDA-registered facilities. Compounded versions aren’t FDA-approved products, because FDA approval applies to mass-produced drugs made the same way for everyone. Most HealthClinic MD patients are prescribed compounded semaglutide or tirzepatide. Brand-name options are also available as an add-on, and your provider can walk you through both.
Choosing
A Clinical Decision, Not a Menu Choice.
Your medical history
Including diabetes, heart disease, sleep apnea and past reactions to medications.
Your goals
How much weight you want to lose, and how fast is safe for you.
How you tolerate it
Some people do better on one than the other.
Cost and availability
Including brand-name and compounded options.
Getting Started
Starting a GLP-1 With HealthClinic MD.
Every patient starts with a free video consultation with a licensed provider. If a GLP-1 is right for you, your provider builds your plan, adjusts your dose over time, and follows up with you through your patient portal. Your medication ships to your door, in any of the 50 states.
Questions
Frequently Asked.
Can I switch from semaglutide to tirzepatide?
Yes. Many people switch if they plateau or have trouble with side effects. Your provider will pick a safe starting dose for the new medication.
How long until I see results?
Most people notice less hunger within the first few weeks. Weight loss builds gradually as your dose increases over several months.
Do I need insurance?
No. HealthClinic MD is cash-pay, and consultations are free.
Will I have to take it forever?
Not necessarily. Your provider will talk with you about a long-term plan, including how to maintain your results if you taper off.