What is Tirzepatide?
Tirzepatide is a once-weekly injectable medication for weight loss and Type 2 diabetes. It's sold as Zepbound (for weight loss) and Mounjaro (for diabetes) by Eli Lilly.
What makes tirzepatide different: it's a "dual agonist" that mimics two hormones (GLP-1 and GIP) instead of just one. This dual action produces stronger appetite suppression and more weight loss than GLP-1-only medications like semaglutide.
| Brand names | Zepbound (weight loss), Mounjaro (diabetes) |
|---|---|
| Manufacturer | Eli Lilly |
| Dosing | Once weekly injection |
| Mechanism | GLP-1 + GIP dual receptor agonist |
| FDA approval | 2022 (diabetes), 2023 (weight loss) |
How Does It Work?
Tirzepatide activates two hormone receptors that regulate appetite and metabolism:
GLP-1 (Glucagon-like Peptide-1): The same pathway targeted by semaglutide. Reduces hunger signals in the brain, slows digestion, and helps regulate blood sugar.
GIP (Glucose-dependent Insulinotropic Polypeptide): The second hormone. Enhances the effects of GLP-1, may improve how your body handles fat, and could reduce nausea compared to GLP-1-only drugs.
Together, these create what some researchers call a "metabolic reset"—more powerful appetite suppression, better blood sugar control, and improved body composition.
The "food noise" effect: Many patients report tirzepatide completely silences the constant mental chatter about food. Not just reduced hunger, but a fundamental shift in how food occupies your thoughts.
How Effective Is It?
The SURMOUNT clinical trials established tirzepatide as the most effective weight loss medication available:
- Average weight loss: 21% at the highest dose (15mg)
- 36% of patients lost more than 25% of body weight
- Head-to-head vs. semaglutide: 47% more weight loss (20.2% vs 13.7%)
For perspective: someone starting at 250 lbs could expect to lose around 50 lbs on tirzepatide. Results that previously required bariatric surgery are now achievable with a weekly injection.
The Dosing Schedule
Tirzepatide uses a gradual titration over 5-6 months. You start low and increase monthly:
Month 1: 2.5mg
Initiation dose. Not expected to produce significant weight loss—just letting your body adjust.
Month 2: 5mg
First therapeutic dose. Many patients start noticing appetite changes here.
Month 3: 7.5mg
Intermediate dose. Some patients achieve great results here and stay.
Month 4: 10mg
Common maintenance dose. Many patients find this their "sweet spot."
Month 5: 12.5mg
Higher dose for those who need more.
Month 6: 15mg
Maximum dose. Not everyone needs to go this high.
Key difference from semaglutide: Tirzepatide offers more "parking spots." Many patients get excellent results at 5mg, 7.5mg, or 10mg without ever reaching the maximum dose. If side effects are tough at one level, you can step back and still see benefits.
Side Effects
Similar to other GLP-1 medications, tirzepatide's most common side effects are gastrointestinal:
- Nausea — Most common, usually improves over weeks
- Diarrhea or constipation — Digestion changes as your gut adjusts
- Decreased appetite — This is also the mechanism of action
- Fatigue — Common in early weeks
- Injection site reactions — Minor, temporary
Interestingly, some patients report tirzepatide causes less nausea than semaglutide. The GIP receptor activation may actually have an anti-nausea effect. Your experience may vary.
Serious risks (rare but important): pancreatitis, gallbladder problems, thyroid tumors (in rodent studies). Not for use if you have personal/family history of medullary thyroid cancer or MEN2 syndrome.
Who Should Consider Tirzepatide?
- Maximum weight loss goal: If you need to lose 20%+ of body weight
- BMI 40+: Higher starting weights often respond well to tirzepatide
- Semaglutide plateau: If you've stalled on semaglutide, tirzepatide often breaks through
- Better tolerability: Some who couldn't tolerate semaglutide do fine on tirzepatide
Cost
Brand-name (Zepbound): ~$1,059/month retail without insurance
Compounded tirzepatide: $250-400/month through telehealth
Tirzepatide costs more than semaglutide in both brand and compounded forms. For many, the extra cost is worth the extra results—but semaglutide at half the price still produces significant weight loss.
How to Get Started
Tirzepatide is available through telehealth providers as a compounded medication or, less commonly, through insurance as brand-name Zepbound. The process:
- Complete an online health assessment
- Consult with a licensed provider
- Get approved and choose your medication
- Receive shipment (cold-chain shipping)
- Begin at 2.5mg, titrate up monthly
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