What Is a GLP-1 Medication?
GLP-1 stands for glucagon-like peptide-1, a hormone your body naturally produces after eating. It signals your brain that you’re full, slows digestion, and helps regulate blood sugar. GLP-1 receptor agonist medications mimic this hormone, which means they help you feel satisfied with less food, reduce cravings, and support your body in burning fat more effectively.
Both semaglutide and tirzepatide work through this mechanism, but there’s one important difference in how tirzepatide goes about it.
Semaglutide: The Original GLP-1 Heavy Hitter
Semaglutide is a GLP-1 receptor agonist. You may have heard of it under brand names like Ozempic (approved for type 2 diabetes) or Wegovy (approved specifically for weight loss). It works by activating GLP-1 receptors, which:
- Reduces hunger and appetite
- Slows gastric emptying (you feel full longer)
- Lowers blood sugar spikes after meals
- Supports fat loss over muscle mass
Clinical results: In the STEP trials, the landmark clinical studies for semaglutide, participants lost an average of 15% of their body weight over 68 weeks. For someone weighing 220 lbs, that’s roughly 33 pounds.
Semaglutide is typically dosed once weekly via subcutaneous injection (a small needle under the skin, most patients are surprised by how easy it is). We start at a low dose and gradually increase over several months to minimize side effects and let your body adjust.
Tirzepatide: The Dual-Action Upgrade
Tirzepatide is newer and adds a second mechanism to the equation. It’s a dual GIP/GLP-1 receptor agonist: meaning it activates both GLP-1 receptors and GIP (glucose-dependent insulinotropic polypeptide) receptors. You may know it as Mounjaro (diabetes) or Zepbound (weight loss).
GIP is another gut hormone involved in regulating insulin and fat storage. By activating both pathways simultaneously, tirzepatide produces a stronger, more synergistic effect on appetite suppression and metabolic function.
Clinical results: In the SURMOUNT trials, tirzepatide produced average weight loss of 20–22% of body weight: significantly more than semaglutide in head-to-head comparisons. At the highest dose, some participants lost close to 25% of their body weight, which is approaching what some surgical interventions achieve.
Like semaglutide, tirzepatide is a once-weekly injection with a gradual dose escalation schedule.
Semaglutide vs. Tirzepatide: Side-by-Side
| Semaglutide | Tirzepatide | |
|---|---|---|
| Mechanism | GLP-1 agonist | Dual GIP + GLP-1 agonist |
| Avg. weight loss | ~15% body weight | ~20–22% body weight |
| Dosing | Once weekly injection | Once weekly injection |
| Common side effects | Nausea, constipation, fatigue | Nausea, constipation, fatigue (similar) |
| Best for | Strong results, proven track record | Maximum weight loss potential |
| Cost (compounded) | Lower | Slightly higher |
Which One Is Right for You?
Consider semaglutide if:
- You want a well-established medication with years of data
- Cost is a primary concern (semaglutide is typically more affordable)
- You’ve done well with GLP-1 medications before
- Your weight loss goal is moderate (20–40 lbs)
Consider tirzepatide if:
- You want to maximize weight loss results
- You have a significant amount of weight to lose (50+ lbs)
- You have insulin resistance or metabolic syndrome alongside obesity
- You’ve tried semaglutide with limited response
- You want the most clinically advanced option available
There is no one-size-fits-all answer. At Sereniva Health, I evaluate each patient individually, your health history, medications, lab work, goals, and lifestyle all factor into which medication makes the most sense for you.
What About Side Effects?
Both medications share a similar side effect profile. The most common ones are:
- Nausea: especially in the first few weeks as your body adjusts. Starting at a low dose and increasing slowly significantly reduces this.
- Constipation or changes in bowel habits
- Fatigue: usually temporary
- Reduced appetite: this is the mechanism working, but can feel like a side effect early on
Serious side effects are rare, but there are contraindications (including a personal or family history of medullary thyroid cancer or MEN2 syndrome), which is why a proper medical evaluation before starting is essential.
Do I Need a Prescription?
Yes. Both semaglutide and tirzepatide are prescription medications. At Sereniva Health, we conduct a full medical evaluation before prescribing, including a consultation, health history review, and lab work.
We prescribe compounded semaglutide and tirzepatide from FDA-registered compounding pharmacies. Compounded versions offer the same active ingredient at a significantly lower cost than brand-name options, making these medications accessible to more patients.
What Does Treatment at Sereniva Health Look Like?
- Initial consultation: We review your health history, goals, and discuss which medication is right for you
- Lab work: We check your baseline metabolic markers
- Prescription + delivery: Your medication ships directly to your door
- Ongoing check-ins: We monitor your progress and adjust dosing as needed
- Lifestyle guidance: Medication works best alongside nutrition and movement
We serve patients in Toms River, Ocean County, Monmouth County, and across New Jersey and New York via telehealth.
Ready to Find Out Which GLP-1 Is Right for You?
The best way to answer that question is with a proper evaluation. I’d love to meet with you, review your health picture, and build a plan tailored specifically to you.
Gina Petrucelli, NP is a board-certified Family Nurse Practitioner and the founder of Sereniva Health, a medical weight loss practice serving patients in Toms River, NJ and via telehealth across New Jersey and New York. She specializes in GLP-1 medication management, metabolic health, and sustainable weight loss.