Dual-Agonist GLP-1 Medication
What is Tirzepatide?
Tirzepatide is Eli Lilly's FDA-approved dual-agonist targeting both GLP-1 and GIP receptors. Sold as Mounjaro (for type 2 diabetes) and Zepbound (for weight loss), it demonstrated up to 21% weight loss in clinical trials.
21%
Max Weight Loss
~5 days
Half-Life
2
Receptor Targets
FDA ✓
Approved
Mounjaro
FDA-approved for type 2 diabetes (May 2022)
Often prescribed off-label for weight loss
Zepbound
FDA-approved for chronic weight management (Nov 2023)
Indicated for BMI ≥30 or ≥27 with weight-related conditions
Tirzepatide Resources
Interactive Tools
Dose Calculator & Plotter
TOOLVisualize tirzepatide levels, track steady state, plan your titration with our free tool.
Units Calculator
TOOLConvert any tirzepatide mg dose into exact insulin syringe units for your vial concentration.
Cost Calculator
TOOLEnter your vial price to see tirzepatide cost per mg, week, month, and year.
Mounjaro Calculator
TOOLMounjaro-specific calculator for diabetes patients tracking tirzepatide.
Zepbound Calculator
TOOLZepbound-specific calculator for weight management patients.
What Is Tirzepatide?
Complete guide to the dual GIP/GLP-1 agonist in Mounjaro and Zepbound: what it is, how it works, and FDA approvals.
Tirzepatide Cost Guide
Brand vs compounded tirzepatide pricing, savings cards, insurance coverage, and how to reduce your out-of-pocket cost.
How Does Tirzepatide Work?
Tirzepatide activates both GIP and GLP-1 receptors. Learn the dual-agonist mechanism behind Mounjaro's weight loss results.
Guides & Articles
Reconstitution Guide
Step-by-step guide to mixing compounded tirzepatide powder with bacteriostatic water.
Complete Dosing Guide
Clinical trial titration schedules, SURMOUNT data, side effects, and best practices.
Microdosing Guide
Split dosing strategies for better tolerability. Reduce nausea while maintaining efficacy.
Side Effects Guide
Common and serious side effects of Mounjaro & Zepbound. Clinical trial data and management tips.
Compounded Tirzepatide Guide
Cost-effective compounded options: sourcing, quality, dosing, and comparison vs brand-name Mounjaro/Zepbound.
Weight Loss Results
SURMOUNT clinical trial results, weight loss timelines, and what to realistically expect at each dose.
How Tirzepatide Works
Tirzepatide is a dual GLP-1/GIP receptor agonist, the first in its class. Activating both receptors produces stronger appetite suppression and better metabolic outcomes than GLP-1-only medications like semaglutide. Clinical trials demonstrated up to 21% tirzepatide weight loss results.
The Two Receptor Targets
GLP-1 (Glucagon-Like Peptide-1)
Reduces appetite, slows gastric emptying, improves insulin sensitivity. Same mechanism as Ozempic/Wegovy.
GIP (Glucose-Dependent Insulinotropic Polypeptide)
Boosts insulin secretion, may improve fat metabolism, and adds weight loss on top of what GLP-1 alone provides.
FDA Approvals & Status
Tirzepatide has three FDA approvals across two brand names. The December 2024 sleep apnea approval was a genuine departure from the diabetes and weight loss indications the drug started with, making Zepbound the first prescription medication ever cleared for obstructive sleep apnea.
| Brand | Indication | Approval date | Status |
|---|---|---|---|
| Mounjaro | Type 2 diabetes management | May 2022 | ✅ Approved |
| Zepbound | Chronic weight management (BMI ≥30, or ≥27 with comorbidity) | November 2023 | ✅ Approved |
| Zepbound | Moderate-to-severe obstructive sleep apnea (OSA) in adults with obesity | December 20, 2024 | ✅ Approved — first-ever OSA drug |
New (December 2024): The FDA approved Zepbound for moderate-to-severe obstructive sleep apnea, the first prescription medication ever cleared for OSA. The approval came from the SURMOUNT-OSA trial, where tirzepatide cut breathing disruptions by 25-29 events per hour and put 42-50% of participants into remission or mild disease.
SURMOUNT clinical trial results
The SURMOUNT program is a set of phase 3 trials that tested tirzepatide across different populations: adults with and without type 2 diabetes, and patients with obstructive sleep apnea.
20.9%
Mean weight loss (SURMOUNT-1, 15mg, 72 weeks)
63%
Lost ≥20% body weight (SURMOUNT-1, 15mg)
14.7%
Weight loss in type 2 diabetes patients (SURMOUNT-2)
SURMOUNT-1 (no T2D)
2,539 adults with obesity or overweight but no type 2 diabetes, followed for 72 weeks. At 15mg, participants lost an average of 20.9% body weight versus 3.1% with placebo. 63% lost 20% or more of their starting weight. This trial was the basis for Zepbound's weight management approval.
SURMOUNT-2 (type 2 diabetes)
938 adults with type 2 diabetes and obesity or overweight, followed for 72 weeks. At 15mg, participants lost 14.7% of body weight and HbA1c dropped by 2.1 percentage points. Weight loss runs lower in T2D populations, though results still outperformed comparators.
SURMOUNT-OSA (sleep apnea)
469 adults with moderate-to-severe obstructive sleep apnea and obesity, followed for 52 weeks. Tirzepatide reduced breathing disruptions by 25-29 events per hour, compared to 5-6 with placebo. 42-50% of participants reached remission or mild disease, versus 14-16% on placebo. Average weight loss was 18-20% (roughly 45-50 lbs). These results supported the December 2024 FDA approval.
Tirzepatide vs. semaglutide
In head-to-head trials, tirzepatide produced 20.2% weight loss versus 13.7% for semaglutide at 72 weeks. 31.6% of tirzepatide patients lost 25% or more body weight, compared to 16.1% on semaglutide. For a full side-by-side breakdown, see the tirzepatide vs. semaglutide comparison.
For full weight loss data and dose-by-dose breakdowns, see the tirzepatide weight loss results guide.
Dosing Schedule
📋 Two dosing approaches: The schedule below is the FDA-approved clinical trial protocol from the SURMOUNT trials. Many users prefer microdosing (split dosing) for better tolerability, especially those using compounded tirzepatide.
The standard titration approach starts at 2.5mg and increases every 4 weeks to minimize gastrointestinal side effects. This is the protocol used in Eli Lilly's SURMOUNT-1 clinical trial.
| Weeks | Weekly Dose | Notes |
|---|---|---|
| 1-4 | 2.5mg | Starting dose (not therapeutic) |
| 5-8 | 5mg | First therapeutic dose |
| 9-12 | 7.5mg | Optional intermediate step |
| 13-16 | 10mg | Higher therapeutic dose |
| 17-20 | 12.5mg | Optional intermediate step |
| 21+ | 15mg | Maximum dose |
Prefer Microdosing?
Many users split their weekly dose into 2-3 smaller injections for smoother drug levels and fewer side effects. This is especially popular with compounded tirzepatide users.
Read the Microdosing Guide →Half-Life & Steady State
Tirzepatide has a half-life of approximately 5 days (120 hours), supporting once-weekly dosing. Steady state is typically reached after 4-5 weeks at a consistent dose.
💡 Pro tip: Use our tirzepatide calculator to visualize how your drug levels build over time and predict when you'll reach steady state.
Common Side Effects
Most Common (>5%)
- Nausea (especially during titration)
- Diarrhea
- Decreased appetite
- Vomiting
- Constipation
- Abdominal pain
Less Common
- Injection site reactions
- Heartburn
- Fatigue
- Hypoglycemia (with other diabetes meds)
- Hair thinning (with rapid weight loss)
If side effects are severe, consider microdosing or staying at your current dose longer before increasing.
Plan Your Tirzepatide Protocol
Use our free calculator to plan your titration and visualize drug levels over time.