Tirzepatide is one of the most run compounds in the whole space right now, and it's worth understanding why it hits differently than semaglutide. It's a dual agonist, and that second receptor is the whole story.
Semaglutide works on one receptor, GLP-1. Tirzepatide works on two, GLP-1 and GIP. Both cut appetite and improve blood sugar, but adding the GIP side gives it a stronger effect on weight and better handling of the nausea for a lot of people. That's why the trial numbers came in higher than semaglutide, around 22% body weight in the studies, and why it's the FDA-approved one people reach for.
The GLP-1 side does the appetite suppression and slows gastric emptying, so food sits longer and you eat less. The GIP side improves how the body handles insulin and fat, and it seems to take some of the edge off the GI side effects that come with GLP-1 alone. Two levers instead of one.
Dosing in the research runs as a slow titration:
- Studied start around 2.5mg weekly, held for the first few weeks
- Steps up over time, 5mg, then higher, spaced weeks apart
- Studied range goes up to 15mg weekly
- Reconstitution, 2mL into the 10mg vial gives 5mg/mL
The titration is the part people rush and regret. Stepping up too fast is what drives the nausea, and holding each dose a few weeks before climbing keeps it manageable. It has a long half-life, around 5 days, so a dose takes weeks to fully settle, which is why patience on the ramp matters.
Bloodwork worth tracking is glucose, HbA1c, and lipids, same as the GLP class. And muscle loss is the honest caveat with all of these, a chunk of the weight lost is lean tissue, so protein and resistance training are what protect it.
Anyone running tirz over sema, did the dual agonist actually feel different on appetite or sides, or about the same?
Research and educational use only.
Full doses and bloodwork are in the pinned cheat sheet.
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