Tirzepatide

FDA-approved (prescription) Evidence grade A — regulator-approved with pivotal randomised trials Updated 2026-10-20

This page describes published research and public regulatory records. It is not medical advice. SoluneFit does not sell, supply, or recommend any compound. The SoluneFit app includes a private, on-device tracker for people who want a record of what they and their clinician have already decided — the app neither suggests compounds nor doses.

Also known as: Mounjaro, Zepbound, LY3298176.

Regulatory status

FDA-approved: Mounjaro (type 2 diabetes, May 2022) and Zepbound (chronic weight management, Nov 2023; obstructive sleep apnoea in obesity, Dec 2024). Prescription only; compounded copies were restricted after the shortage was declared resolved in Dec 2024 [1][2].

What it is

Dual GIP and GLP-1 receptor agonist (39-amino-acid synthetic peptide with a C20 fatty diacid).

A once-weekly injected peptide that activates both the GIP and GLP-1 receptors. Approved in the US for type 2 diabetes (Mounjaro) and for chronic weight management and obstructive sleep apnoea in obesity (Zepbound).

What the published research shows

SURPASS (diabetes) and SURMOUNT (weight) phase 3 programmes, thousands of participants, 72-week endpoints.

Published human studies and reports (these describe trial populations, not SoluneFit claims):

Type 2 diabetes (Mounjaro label): 2.5 mg once weekly for 4 weeks to start, then 5 mg once weekly; increases of 2.5 mg at intervals of at least 4 weeks up to 15 mg once weekly.
Chronic weight management (Zepbound label): Same 2.5 mg start and 2.5 mg steps every 4 weeks or more; maintenance 5, 10 or 15 mg once weekly.
Weight loss in adults with obesity without diabetes (SURMOUNT-1 trial): At 72 weeks, mean weight change was about −15 % (5 mg), −19.5 % (10 mg) and −20.9 % (15 mg) versus −3.1 % with placebo.

Mechanism, as reported

Enhances glucose-dependent insulin secretion, lowers glucagon, slows gastric emptying and reduces appetite through central GLP-1 and GIP signalling. The fatty-acid side chain binds albumin, which is what makes it last a week.

Practical record

Elimination half-life: 120.0 h (confidence: high). Terminal half-life about 5 days; steady state after about 4 weekly doses; subcutaneous bioavailability about 80 %; apparent volume of distribution about 10.3 L.
Studied routes: subcutaneous.
Typical supply: Single-dose pens and vials, 2.5 / 5 / 7.5 / 10 / 12.5 / 15 mg per 0.5 mL (Rx).
Reconstitution: Supplied as a ready solution; not reconstituted.
Storage: Refrigerate 2–8 °C in the carton; may be kept unrefrigerated up to 30 °C for up to 21 days; do not freeze.

Safety signals on record

Reported adverse events: Mostly gastrointestinal: nausea, diarrhoea, decreased appetite, vomiting, constipation, dyspepsia, abdominal pain; injection-site reactions; hypoglycaemia when combined with insulin or sulfonylureas.
Contraindications: Boxed warning for thyroid C-cell tumours in rodents: contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2. Warnings for pancreatitis, gallbladder disease, acute kidney injury from dehydration, severe GI disease, diabetic retinopathy complications and suicidal thoughts (Zepbound).
Interactions: Delays gastric emptying, so oral medicines with a narrow therapeutic window may absorb differently; oral contraceptive absorption is reduced for 4 weeks after starting and after each dose increase (use a barrier method); insulin and sulfonylurea doses may need lowering.
Notes: Not recommended during pregnancy. Dehydration from GI effects can hurt the kidneys, so fluid intake matters for anyone with reduced kidney function.

Sources

General wellness education, not medical advice. Unapproved compounds have no established dosing, purity standard, or safety profile.

← All compounds