Interested in this peptide?
Request more information and our team will get back to you within 2 business days.
What Is Tirzepatide?
Tirzepatide is a first-in-class dual glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptor agonist developed by Eli Lilly. By activating both incretin receptors, it produces greater metabolic effects than GLP-1-only drugs like semaglutide.
Tirzepatide has produced unprecedented weight loss results in clinical trials, establishing it as the most effective obesity medication currently available.
Key Characteristics
- Novel Mechanism: First dual GIP/GLP-1 agonist
- Weight Loss: Up to 22.5% in trials (highest ever for a medication)
- Administration: Once-weekly subcutaneous injection
- Doses: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg
Mechanism of Action
Dual Incretin Activation
Tirzepatide activates two key metabolic hormone receptors:
GLP-1 Receptor Effects
- Enhanced glucose-dependent insulin secretion
- Reduced glucagon secretion
- Slowed gastric emptying
- Reduced appetite via CNS effects
GIP Receptor Effects
- Additional insulin secretion enhancement
- Improved fat tissue metabolism
- Potential bone health benefits
- Complementary satiety effects
Why Dual Agonism Works Better
- GIP and GLP-1 act on different cell populations
- Synergistic effects on insulin secretion
- GIP may reduce GLP-1 associated nausea
- Enhanced fat tissue effects from GIP
- Greater overall metabolic impact
Clinical Trial Results
SURPASS Trials (Type 2 Diabetes)
| Trial | Comparator | HbA1c Reduction | Weight Loss |
|---|---|---|---|
| SURPASS-1 | Placebo | -1.9 to -2.1% | -7 to -9.5 kg |
| SURPASS-2 | Semaglutide 1mg | Superior | Superior (-5.5 kg more) |
| SURPASS-3 | Insulin degludec | Superior | -12 kg vs +2 kg |
| SURPASS-4 | Insulin glargine | Superior | Superior |
SURMOUNT Trials (Obesity)
| Trial | Population | Weight Loss (15mg) | Key Finding |
|---|---|---|---|
| SURMOUNT-1 | Obesity without diabetes | -22.5% | Unprecedented weight loss |
| SURMOUNT-2 | Obesity with diabetes | -15.7% | Superior to placebo |
| SURMOUNT-3 | After intensive lifestyle | -18.4% additional | Maintenance/enhancement |
| SURMOUNT-4 | Withdrawal study | Continued vs regain | Sustained treatment needed |
Comparison: Tirzepatide vs Semaglutide
Head-to-Head Comparison
- Weight loss: Tirzepatide ~22% vs Semaglutide ~15% (at highest doses)
- HbA1c reduction: Tirzepatide superior in SURPASS-2
- Mechanism: Dual vs single incretin
- GI side effects: Similar profiles, possibly less nausea with tirzepatide
- Dosing: Both weekly injection
Side Effects
Common Side Effects
- Nausea (tends to improve with time)
- Diarrhea
- Vomiting
- Constipation
- Abdominal pain
- Decreased appetite
- Injection site reactions
Serious Risks
- Pancreatitis (rare)
- Gallbladder disease
- Hypoglycemia (especially with insulin/sulfonylureas)
- Thyroid C-cell tumors (boxed warning; rodent studies)
- Acute kidney injury (from dehydration)
Ongoing Research
Active investigation areas:
- Heart failure: Studies on HFpEF
- Sleep apnea: SURMOUNT-OSA showing improvements
- NASH/MASLD: Liver fat reduction studies
- Cardiovascular outcomes: Long-term CV benefit trials
- Kidney disease: Nephroprotection research
Key Published Research
| Year | Study | Key Finding | Journal |
|---|---|---|---|
| 2021 | SURPASS-2 | Superior to semaglutide in T2D | NEJM |
| 2022 | SURMOUNT-1 | 22.5% weight loss | NEJM |
| 2023 | SURMOUNT-2 | Weight loss in diabetes | Lancet |
| 2024 | SURMOUNT-OSA | Sleep apnea improvements | NEJM |
Future Directions
Tirzepatide represents a platform for further development:
- Retatrutide: Lilly's triple agonist (GIP/GLP-1/glucagon) showing ~24% weight loss
- Oral formulations: Under development
- Combination therapies: With other agents
- Broader indications: Beyond diabetes and obesity
Prescription Medication
Tirzepatide (Mounjaro, Zepbound) is a prescription medication that should only be used under medical supervision. It is not available for research purchase. This information is for educational purposes about dual incretin science. Always consult healthcare providers for medical decisions.
Summary
Tirzepatide has revolutionized metabolic medicine by demonstrating that dual GIP/GLP-1 agonism produces superior results to GLP-1 alone. With weight loss approaching that of bariatric surgery (~25%) and excellent glycemic control, it represents the new benchmark for obesity and diabetes pharmacotherapy. The platform approach — combining multiple incretin pathways — is likely to drive further innovation in this field.