Semaglutide vs. Tirzepatide: What's the Difference?
Both are once-weekly injections that support significant weight loss — but they work on different hormones, and that changes how effective, and how expensive, each one tends to be.
The short answer
Semaglutide targets one gut hormone (GLP-1). Tirzepatide targets two (GLP-1 and GIP). That dual action is why tirzepatide tends to produce somewhat greater average weight loss in clinical trials — but semaglutide is well-studied, generally well-tolerated, and costs less. Which one is "better" depends on your goals, budget, and how your body responds, which is exactly what your provider evaluation is for.
How They Work
Semaglutide
A GLP-1 receptor agonist — it mimics a hormone your gut releases after eating, which slows digestion, reduces appetite, and helps regulate blood sugar. It's the medication behind the diabetes brand Ozempic and the weight-loss brand Wegovy (an oral form is sold as Rybelsus).
Tirzepatide
A dual GLP-1/GIP receptor agonist — it acts on GLP-1 the same way semaglutide does, plus a second hormone (GIP) that appears to add to the appetite-reducing and blood-sugar effects. It's the medication behind the diabetes brand Mounjaro and the weight-loss brand Zepbound.
At Quill Health, your prescription is written and dosed by Dr. Bacala based on your evaluation — the mechanism above is general medical background, not a claim about a specific product or manufacturer.
Effectiveness: What the Trials Showed
Semaglutide — STEP 1 Trial
Averaged about 15% body weight loss at 68 weeks, compared to roughly 2–3% in the placebo group.
Tirzepatide — SURMOUNT-1 Trial
Averaged 16–22.5% body weight loss at 72 weeks, depending on dose (5mg, 10mg, or 15mg).
Across the published trial data, tirzepatide shows a modest edge in average weight loss, largely attributed to its dual hormone action. That said, these are trial averages, not guarantees — individual results vary with dose, consistency, and lifestyle factors, and some patients do just as well on semaglutide with a simpler, lower-cost regimen.
Side Effects & Safety
What to Expect
Both medications share a similar side effect profile: nausea, mild digestive upset, constipation, or fatigue, especially during dose increases. These usually improve over time. Tirzepatide's higher doses are sometimes associated with a somewhat higher rate of GI side effects. Dr. Bacala titrates your dose gradually to minimize discomfort.
Contraindications & cautions
- Do not use if you have a personal or family history of medullary thyroid carcinoma (MTC) or MEN2.
- Do not use during pregnancy or while breastfeeding.
- Do not use if you've had a serious allergic reaction to semaglutide, tirzepatide, or any component.
- Use with caution if you have a history of pancreatitis, severe GI disease (e.g., gastroparesis), gallbladder disease, or significant renal impairment.
This list isn't exhaustive — see our full Weight Loss Program page and FAQ. Dr. Bacala will review your full history to determine safety and eligibility.
Pricing at Quill Health DPC
Semaglutide Program
- Includes 3 months of medication
- Starter injection kit
- Ongoing physician support
Tirzepatide Program
- Includes 3 months of medication
- Starter injection kit
- Ongoing physician support
This is a self-pay program, consistent with our direct primary care model — we don't bill insurance, Medicare, or Medicaid for it.
So Which One Is Right for You?
As a general guide: if you want the medication with the longest track record and a lower monthly cost, semaglutide is a strong, well-established choice. If you're aiming for the greatest possible average weight loss and cost is less of a factor, tirzepatide's dual mechanism may get you there faster. Many patients also switch between the two if their first choice isn't producing the results or tolerability they want. Dr. Bacala reviews your history and goals during your evaluation and helps you choose — or switch — based on how you actually respond, not just trial averages.
Common Questions
In clinical trials, tirzepatide has shown a modest edge in average weight loss over semaglutide, largely because it acts on two gut hormones (GLP-1 and GIP) instead of one. But "better" depends on the person — some patients respond just as well to semaglutide with fewer side effects, and cost is a factor too. Your provider can help you weigh both.
Yes, many patients switch between the two if their current medication isn't producing the results or tolerability they want. Any switch should be guided by your provider, who will help you re-titrate the dose safely.
At Quill Health Direct Primary Care in Las Vegas, the Semaglutide Program is $550 and the Tirzepatide Program is $750, each covering 3 months of medication, a starter injection kit, and ongoing physician support. This is a self-pay program — insurance, Medicare, and Medicaid are not billed.
Both medications share similar gastrointestinal side effects — nausea, mild digestive upset, constipation, and fatigue — especially during dose increases. These typically improve over time as your provider titrates your dose.
Ready to Talk to Dr. Bacala About Your Options?
Get the full program details, pricing, and start the discovery call process on our Weight Loss Program page.
Go to Weight Loss Program & Get Started