Tirzepatide 15mg Guide & Tableau de Dose

What is Tirzepatide 15mg?

Tirzepatide — sold under the brand name Mounjaro® — is a research peptide that belongs to a class called dual incretin agonists. That's a fancy way of saying it mimics two gut hormones at once: GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1).^[5] Most older drugs in this space only target GLP-1, so tirzepatide's two-target approach makes it genuinely novel — it's described as "first-in-class."^[2]

The 15 mg dose is the highest weekly dose studied in the major clinical trial program (the SURPASS trials) and represents the maximum maintenance dose investigated for glycaemic control in type 2 diabetes research.^[1] This page covers the 15 mg protocol specifically. Researchers exploring lower doses should visit the main tirzepatide chart.

Important note: This page is for research and educational reference only. Tirzepatide is a research compound on this platform. Nothing here is medical advice.

How Tirzepatide 15mg Works

Think of your gut as a messaging system. When you eat, your intestines release hormones — GIP and GLP-1 — that act like texts to the pancreas saying "hey, release some insulin." Tirzepatide is a synthetic molecule that pretends to be both of those hormones at the same time, activating both their receptors simultaneously.^[5]

Here's what that triggers in research models:

• More insulin release — but only when blood sugar is actually elevated, which reduces hypoglycaemia risk.^[2]
• Less glucagon — glucagon is the hormone that raises blood sugar, so dialling it down helps keep glucose levels in check.^[5]
• Slower stomach emptying — food moves through your digestive system more gradually, blunting sugar spikes after meals.^[5]
• Reduced appetite and improved satiety — subjects in trials felt fuller, which contributed to significant weight loss.^[5]

GIP also plays its own unique role in fat and energy metabolism, which researchers believe amplifies the weight-loss effects beyond what GLP-1 alone can achieve.^[5]

What the Research Shows

Most of what we know about tirzepatide 15 mg comes from the SURPASS clinical trial program — a series of five phase III trials.^[1] Here are the headline findings in plain language:

• Blood sugar control: In a large network meta-analysis comparing 10 GLP-1 class agents added to metformin, tirzepatide 15 mg produced the largest average HbA1c reduction of all agents studied — approximately −2.23%.^[4] HbA1c is a 3-month average blood sugar measure; lower is better in diabetes research.
• Body weight: The same analysis found tirzepatide 15 mg was associated with an average body weight reduction of around −11.33 kg — again the largest of any agent in the comparison.^[4]
• Head-to-head comparisons: In the SURPASS trials, once-weekly tirzepatide outperformed the GLP-1 agonists dulaglutide and semaglutide 1 mg for both glycaemic control and weight loss.^[2]
• Hypoglycaemia risk: Across GLP-1 class agents including tirzepatide, researchers did not observe an increased incidence of hypoglycaemia (dangerously low blood sugar).^[4]
• Safety profile: Tirzepatide was generally well tolerated. The most common adverse events were gastrointestinal — nausea, diarrhoea, decreased appetite, and vomiting — and these were mostly mild to moderate.^[2] No increased risk of major adverse cardiovascular events was observed.^[2]
• Rapid uptake in real-world data: Following its 2022 approval, Mounjaro showed the fastest monthly growth rate (254.3%) of any GLP-1 class agent tracked in a large University of California health system dataset — a signal of the significant research and clinical interest in this compound.^[6]

What Tirzepatide 15mg Is Being Studied For

Tirzepatide received its first regulatory approval in the USA in May 2022 for improving glycaemic control in adults with type 2 diabetes, as an adjunct to diet and exercise.^[5] Beyond that, researchers are actively investigating tirzepatide across a broad range of metabolic and cardiovascular conditions, including:

• Obesity and weight management^[5]
• Cardiovascular disorders in type 2 diabetes^[5]
• Heart failure^[5]
• Non-alcoholic steatohepatitis (fatty liver disease)^[5]
• Obstructive sleep apnoea^[5]
• Reducing mortality and morbidity associated with obesity^[5]

Several of these areas are in phase II or phase III trials, meaning the evidence base is still developing.^[5]

How Tirzepatide 15mg Is Dosed in Research

The 15 mg weekly subcutaneous dose is the maximum maintenance dose evaluated in the SURPASS trials for glycaemic control.^[1] Research protocols typically use a gradual dose-escalation schedule before reaching 15 mg, in order to manage gastrointestinal side effects. The full breakdown — including starting doses, escalation steps, and injection timing — is laid out in the dosage chart on this page. You can also use the calculator to work through weight-based or protocol-specific figures. Always refer to the trial-sourced numbers in the chart rather than estimating independently.

Mixing and Storing Tirzepatide 15mg

In clinical trials, tirzepatide was supplied as single-dose prefilled pens and single-dose vials for subcutaneous (under-the-skin) injection.^[2] For research settings using lyophilised (freeze-dried) powder, standard peptide reconstitution practice applies: use bacteriostatic water, add the solvent slowly down the side of the vial (never inject directly onto the powder), and swirl gently — never shake. Once reconstituted, store the vial refrigerated at 2–8 °C and protect it from light. Discard any unused solution per your lab's protocol. Reconstituted peptides are generally considered stable for a limited window, so prepare only what is needed. Always check your specific supplier's documentation for product-specific storage guidance.

Sources

1. New Drug: Tirzepatide (Mounjaro(™)). — The Senior care pharmacist, 2023. PMID 36751934.
2. Tirzepatide: A Review in Type 2 Diabetes. — Drugs, 2024. PMID 38388874.
3. Tirzepatide (Mounjaro®, Zepbound®). — , 1994. PMID 39038307.
4. Comparison of the efficacy and safety of 10 glucagon-like peptide-1 receptor agonists as add-on to metformin in patients with type 2 diabetes: a systematic review. — Frontiers in endocrinology, 2023. PMID 37701904.
5. Tirzepatide: First Approval. — Drugs, 2022. PMID 35830001.
6. Trends in glucagon-like peptide 1 receptor agonist use, 2014 to 2022. — Journal of the American Pharmacists Association : JAPhA, 2024. PMID 37821008.