Tirzepatide

Dual GIP/GLP-1 Receptor Agonist

Tirzepatide hits two receptors instead of one — GIP and GLP-1 — which suppresses appetite and improves insulin sensitivity through separate pathways. Clinical trials showed it beats semaglutide on raw weight loss numbers (22.5% vs 15%), and people generally report less nausea. The titration matters just as much as with sema — start at 2.5mg, hold each dose for at least 4 weeks, and your gut will cooperate better than if you rush it.

Protocol

Dose: 2.5mg-15mg per week (titrated up) | Frequency: Once weekly | Cycle: Ongoing (not cycled) | Route: SubQ

Reconstitution: 2mL bacteriostatic water per 10mg vial for compounded versions. Use our free reconstitution calculator for exact syringe units.

Effects

• Weight loss (90%) — Up to 22.5% body weight reduction in 72-week trials, with nearly two-thirds of participants losing 20%+ at the highest dose
• Appetite suppression (88%) — Dual-receptor activation produces profound satiety, often described as food just not being interesting anymore
• Improved insulin sensitivity (72%) — Significant A1C and fasting glucose improvements even in non-diabetics
• Waist circumference reduction (80%) — Average reduction of ~13cm in waist circumference in clinical trials

Side Effects

• Nausea (31%) — Lower nausea rates than sema, but still the most common side effect. Worst during dose bumps, then it settles.
• Diarrhea (23%) — Can hit at any dose level. Stays mild for most people. Hydrate more than you think you need to.
• Constipation (18%) — Less common than with sema but still happens. Fiber, water, maybe magnesium.
• Vomiting (12%) — Usually only when the dose goes up. Smaller meals help a lot — your stomach is working differently now.
• Injection-site reactions (7%) — Mild red spot or some itching where you pinned. Nothing serious.

Evidence

Strong evidence — FDA-approved as Mounjaro (diabetes) and Zepbound (obesity). The SURMOUNT trials showed up to 22.5% body weight loss — more than semaglutide in head-to-head comparisons. Dual mechanism (GIP + GLP-1) appears to cause fewer GI side effects than GLP-1 alone.

Approval status: FDA-approved (branded)

References

1. Rosenstock J, et al. Efficacy and safety of a novel dual GIP and GLP-1 receptor agonist tirzepatide in patients with type 2 diabetes (SURPASS-1): a double-blind, randomised, phase 3 trial. Lancet, 2021. PMID: 34186022
2. Frías JP, et al. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med, 2021. PMID: 34170647
3. Jastreboff AM, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med, 2022. PMID: 35658024
4. Garvey WT, et al. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet, 2023. PMID: 37385275

Storage

• Lyophilized: Refrigerate at 2-8C. Stable for 6+ months sealed.
• Reconstituted: Refrigerate. Use within 28 days.
• Water: Bacteriostatic water, 2mL per 10mg vial for compounded versions.
• Needle: 30-31 gauge, 0.5 inch for subcutaneous injection

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These statements have not been evaluated by the FDA. This content is for educational purposes only and is not intended to diagnose, treat, cure, or prevent any disease. Consult a healthcare professional before starting any protocol.

vialprep research · Sources: PubMed, FDA, peer-reviewed trials · How we verify