Tirzepatide
Dual GIP/GLP-1 receptor agonist FDA-approved for type 2 diabetes (Mounjaro) and weight management (Zepbound).
🔬 Mechanism of Action
Tirzepatide is the first dual GIP/GLP-1 receptor agonist — a novel mechanism that activates both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors simultaneously. This dual-agonist approach amplifies the metabolic effects beyond what GLP-1 agonism alone achieves.
Tirzepatide enhances insulin secretion, suppresses glucagon, slows gastric emptying, and acts centrally to reduce appetite. The addition of GIP receptor activation improves adipose tissue insulin sensitivity and may enhance fat oxidation. Clinical trials (SURMOUNT-1) demonstrated up to 22.5% body weight reduction at the 15 mg dose — the highest weight loss achieved by any single pharmacological agent. FDA-approved as Mounjaro for type 2 diabetes and Zepbound for weight management.
Source: FDA Label (Mounjaro), PMID: 35658024 (SURMOUNT-1)
📜Background & History
Tirzepatide (LY3437943) was developed by Eli Lilly as the first "twincretin" — a single molecule activating both GIP and GLP-1 receptors. Approved as Mounjaro in 2022 for T2D and Zepbound in 2023 for obesity, it achieved 22.5% body weight reduction in the SURMOUNT-1 trial — surpassing all prior pharmacological weight loss agents. The GIP component improves adipose tissue insulin sensitivity and may mitigate GLP-1-induced nausea, making tirzepatide better tolerated than pure GLP-1 agonists.
🎯 Research Use Cases
- ✓Type 2 diabetes with cardiovascular comorbidity
- ✓Obesity treatment with superior weight loss vs semaglutide
- ✓Metabolic syndrome: improves insulin resistance, lipids, and blood pressure
- ✓Obstructive sleep apnea (FDA approved 2024)
- ✓Compounded research: body recomposition and metabolic optimization
💉 Dosing Protocol
| Typical Dose | 2.5-15 mg/week |
| Frequency | 1× weekly |
| Half-Life | ~120 hours (5 days) |
| Common Vial Sizes | 5 mg, 10 mg, 15 mg, 30 mg |
🧪 Reconstitution Example
⚠️Safety & Considerations
FDA-approved for type 2 diabetes and weight management. Common side effects include nausea, diarrhea, and decreased appetite (typically during dose escalation). Same MTC/MEN 2 contraindications as semaglutide. Dose escalation over 20+ weeks minimizes GI side effects.
⚡Interactions & Contraindications
Same contraindications as semaglutide: MTC/MEN2 history. Do not combine with other GLP-1 or GIP agonists. MK-677 (and other GH secretagogues) may partially oppose insulin-sensitizing effects — monitor fasting glucose. Warfarin/anticoagulant patients should monitor INR during dose escalation.
🔗Synergies & Common Stacks
BPC-157 may attenuate GI side effects of tirzepatide during dose escalation via gastroprotective and anti-inflammatory mechanisms.
In body recomposition protocols, tirzepatide drives fat loss while MK-677 supports GH-mediated muscle preservation — but monitor for insulin resistance interaction.
❓ Frequently Asked Questions
What makes tirzepatide different from semaglutide?▼
What is the tirzepatide dose escalation schedule?▼
How do I calculate tirzepatide syringe units from a compounded vial?▼
📖 References
- Jastreboff AM, et al. “Tirzepatide once weekly for the treatment of obesity (SURMOUNT-1).” N Engl J Med (2022). PMID: 35658024
- Frias JP, et al. “Tirzepatide versus semaglutide once weekly in patients with type 2 diabetes (SURPASS-2).” N Engl J Med (2021). PMID: 34170647