Peptide ScheduleTirzepatide
Benefits
About Tirzepatide
Tirzepatide is a dual GIP/GLP-1 receptor agonist, sold as Mounjaro (diabetes) and Zepbound (obesity). It targets two incretin hormones simultaneously, producing greater weight loss than semaglutide in head-to-head trials (up to 22.5% vs 15%). GIP activation enhances fat metabolism and may improve tolerability compared to GLP-1-only drugs.
Who Should Consider Tirzepatide
- Adults with BMI ≥30 (or ≥27 with weight-related comorbidity)
- Type 2 diabetics needing superior glycemic control
- Patients who plateaued on semaglutide or liraglutide
- Those seeking the most potent FDA-approved weight-loss injectable
- Adults with obesity-related cardiovascular risk factors
How Tirzepatide Works
Tirzepatide activates both GIP and GLP-1 receptors. GLP-1 receptor activation suppresses appetite, slows gastric emptying, and enhances insulin secretion. GIP receptor activation improves fat metabolism, enhances insulin sensitivity, and may reduce nausea compared to GLP-1-only agonists. The dual mechanism produces superior weight loss and glycemic control.
What to Expect
Starting dose 2.5mg weekly. Appetite suppression begins within days. Nausea is most common but usually mild. Minimal weight loss expected — this is a tolerability phase.
Dose escalated to 5mg. Noticeable hunger reduction. Early weight loss of 2-4% body weight. GI side effects typically improving.
Dose escalated to 7.5mg. Steady weight loss continues. Blood sugar improvements measurable on labs.
Dose escalated to 10mg. Significant appetite changes. Cumulative weight loss approaching 8-10%.
Dose escalated to 12.5mg, then 15mg if tolerated. Maximum efficacy phase begins. SURMOUNT-1 showed 22.5% weight loss at 72 weeks on 15mg.
Maintenance at maximum tolerated dose (5-15mg). Weight loss continues to plateau around 20-25%. Cardiovascular and metabolic markers significantly improved.
Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 2,500mcg | Weekly |
| Moderate | 5mg | Weekly |
| Aggressive | 10mg | Weekly |
Note: Dual GIP/GLP-1 agonist (Mounjaro/Zepbound). Titrate from 2.5mg. More potent weight loss than semaglutide in trials.
How to Inject Tirzepatide
Inject subcutaneously once weekly into abdomen, thigh, or upper arm. Rotate sites. Titrate slowly — increase dose every 4 weeks to minimize GI side effects.
Cycling Protocol
Intended for long-term use. Weight regain expected upon discontinuation. Maintenance dosing may be lower than escalation dose.
Pharmacokinetics
Source: Mounjaro FDA Label, Section 12.3; confirmed by PopPK analysis (t½ ~117h)
Pharmacokinetics — Active Dose Over Time
t½ = ~5 daysDisclaimer: This curve is a simplified first-order exponential decay model. Actual pharmacokinetics vary based on injection site, individual metabolism, body composition, and other factors. Half-life values are approximate and based on available preclinical and clinical literature. Many research peptides lack formal human pharmacokinetic studies. This is for educational purposes only — not medical advice.
Side Effects
BLACK BOX WARNING: Tirzepatide causes thyroid C-cell tumors in rodents. It's unknown whether it causes thyroid C-cell tumors, including medullary thyroid carcinoma (MTC), in humans. Contraindicated in patients with a personal or family history of MTC or MEN2. Common side effects: nausea (12-18%), diarrhea (12-17%), decreased appetite, vomiting, constipation. GI effects are usually mild-to-moderate and improve with slow dose titration. Rare: pancreatitis, gallbladder disease, hypersensitivity reactions.
Contraindications
- Personal or family history of medullary thyroid carcinoma (MTC)
- Multiple Endocrine Neoplasia syndrome type 2 (MEN2)
- History of pancreatitis or active pancreatitis
- Pregnancy or planning to become pregnant (stop at least 2 months before conception)
- Breastfeeding
- Known hypersensitivity to tirzepatide or any excipients
- Severe gastrointestinal disease (e.g., gastroparesis)
Drug Interactions
- Insulin and sulfonylureas — increased hypoglycemia risk; dose reduction often needed
- Oral contraceptives — reduced efficacy due to delayed gastric emptying; use barrier method for 4 weeks after initiation and each dose escalation
- Oral medications with narrow therapeutic index (e.g., warfarin) — monitor closely due to delayed gastric emptying
- Other GLP-1 receptor agonists (semaglutide, liraglutide) — do not combine; overlapping mechanism
- Oral medications requiring threshold concentrations — absorption timing may shift; monitor efficacy
Storage & Stability
Molecular Profile
Related Peptides
References
- SURMOUNT-1 — Tirzepatide Once Weekly for the Treatment of ObesityPubMed 35658024
- SURPASS-1 — Tirzepatide vs Placebo in Type 2 DiabetesPubMed 34170647
- SURPASS-2 — Tirzepatide vs Semaglutide in Type 2 DiabetesPubMed 34170646
- Mounjaro (Tirzepatide) FDA Prescribing InformationFDA Label
- Zepbound (Tirzepatide) FDA Prescribing InformationFDA Label
- Population Pharmacokinetics of TirzepatidePubMed