GLP-1 / Weight Loss

Tirzepatide

Half-life: 117h Subcutaneous injection (abdomen, thigh, or upper arm); rotate sites. Once weekly, same day each week.

Warnings. Boxed warning for thyroid C-cell tumors in rodents. Avoid with MTC/MEN2 history. GI side effects common during escalation.

Mechanism

Dual agonist of GIP and GLP-1 receptors; enhances insulin secretion, suppresses appetite, slows gastric emptying, and improves insulin sensitivity through complementary incretin pathways.

Overview

Tirzepatide is a dual GIP/GLP-1 receptor agonist approved for type 2 diabetes (Mounjaro) and chronic weight management (Zepbound). It produced greater average weight loss than semaglutide in trials, up to roughly 20% of body weight. Dosed once weekly with gradual titration.

Protocols

Standard Titration (Zepbound Schedule)

Official BEGINNER

Full titration from 2.5mg to 15mg weekly, escalating in 4-week intervals as tolerated.

Goal: Weight loss

Step 1 4w

2.5 mg · 1×/day

2.5mg once weekly - initiation dose.

Step 2 4w

5 mg · 1×/day

5mg once weekly.

Step 3 4w

7.5 mg · 1×/day

7.5mg once weekly.

Step 4 4w

10 mg · 1×/day

10mg once weekly.

Step 5 4w

12.5 mg · 1×/day

12.5mg once weekly.

Step 6 4w

15 mg · 1×/day

15mg once weekly - maximum dose. Escalate only if tolerated and additional effect desired.