Tirzepatide
aka Mounjaro, Zepbound
Hits two appetite-and-insulin hormones at once. Sold as Mounjaro and Zepbound.
Technically · Dual agonist (GLP-1 + GIP)
In one sentence
The most powerful FDA-approved weight-loss shot — up to 22.5% weight loss at the top dose.
— Ozempic's upgraded twin — hits one more receptor (GIP) for stronger appetite control.
Half-life
~5 days
Stays active about 5 days — one shot per week.
Dosing
Once weekly
How often you take a dose
Route
SubQ
How it goes into the body
Status
FDA
Approved by the FDA for prescription use
What it is
The most powerful weight-loss drug the FDA has approved. It mimics two of your gut hormones (GLP-1 and GIP) to crush appetite, slow your stomach down, and steady your blood sugar. In its trial, top dose lost 22.5% body weight in just over a year.
The full technical answer
FDA-approved dual GLP-1/GIP agonist marketed as Mounjaro (T2D) and Zepbound (obesity). Outperforms semaglutide on weight loss in head-to-head trials.
How it works
After you eat, your gut releases GLP-1 and GIP — they signal "you're full, sugar is handled." Tirzepatide is a synthetic version of those signals but stronger and longer-lasting. Result: smaller portions feel satisfying, cravings fade, and your body manages food more efficiently.
The full technical answer
Activates both GLP-1 and GIP receptors. Suppresses appetite, slows gastric emptying, enhances glucose-dependent insulin secretion.
What the research says
SURMOUNT-1 trial showed up to 22.5% weight loss at 72 weeks at 15mg weekly.
Sources: NEJM SURMOUNT-1 · FDA label (Zepbound)
Common dosing ranges
- Range
- Start 2.5 mg/week, titrate to 15 mg/week max per FDA label
- Frequency
- Once weekly
- Duration
- Long-term per FDA label
Sources: FDA Zepbound label
How to take it
Practical guidance synthesized from clinical protocols, FDA labels, and clinician interviews. Always cross-check with a prescribing physician.
Best time of day
Once a week, any day, any time of day per FDA label. Pick a day you'll remember (most people pick Sunday).
With food or fasted
With or without — doesn't affect the drug. Eat lighter, lower-fat meals the first few days after injection to reduce nausea.
How long to cycle
Long-term per FDA label. Titrate every 4 weeks: 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg.
When to get off
Severe abdominal pain, persistent vomiting, or a new neck lump → stop and call a doctor immediately. Don't push past a dose step that causes lasting side effects.
Administration
Side effects
Common
- Nausea
- Diarrhea
- Vomiting
- Constipation
- Abdominal pain
Serious / theoretical
- Pancreatitis
- Gallbladder disease
- Thyroid C-cell tumor warning
Sources: FDA label
Further reading & listening
Where the experts go deeper.
Curated from the PeptideFacts expert directory — vetted YouTube channels, podcasts, books, and communities. No anecdote-only or supplier-affiliated picks.
Videos
Dr. Jones DC — GLP-1 dose management playlist
Dr. Jones, DC — 700+ short clinical videos on titration, side-effect handling, and stalls
Dr Trevor Bachmeyer — three-failures framework applied to GLP-1
Dr Trevor Bachmeyer — Why GLP-1 stalls trace back to inflammation, insulin resistance, or mitochondria
Peptide Protocol — Tirzepatide 101
Peptide Protocol — Beginner-friendly overview
Podcasts
Books
Communities