Tirzepatide
A dual GIP and GLP-1 receptor agonist, the same molecule sold as Mounjaro and Zepbound. People run it for appetite control and weight loss, taken as a once-weekly subcutaneous shot that quiets hunger and slows the stomach.
Where to buy Tirzepatide, cheapest first.
The one vetted vendor we found currently listing Tirzepatide. We link straight to its product page and grade it on public lab data. As more vendors list it, they’ll show up here, cheapest first.
Tirzepatide
What Tirzepatide actually does.
The simple version first, then a little more for the curious. No biochem degree required.
It hits two appetite switches at once, the GIP and GLP-1 receptors, so you feel full sooner, eat less, and your blood sugar stays steadier.
How it works
Tirzepatide is a 39 amino acid peptide that activates both the GIP and GLP-1 receptors, the two gut hormone pathways that tell your brain you are full. Hitting both at once is what sets it apart from single-receptor drugs like semaglutide.
Where it acts
It works on the brain's appetite centers, the pancreas, and the gut. It slows how fast the stomach empties, prompts glucose-dependent insulin release, and dials down glucagon, so you stay full longer and blood sugar runs steadier.
What people notice
Most people report a sharp drop in appetite and food noise within the first weeks, then steady weight loss over months. A C20 fatty acid tail gives it a roughly five-day half-life, which is why one shot a week is enough.
Honest caveat: tirzepatide is unusually well studied for a research peptide, with large human trials behind the approved Mounjaro and Zepbound products. But the vials sold by research vendors are not those approved medicines, are not quality controlled the same way, and are sold strictly for research use only. None of this is medical advice, talk to a licensed provider before starting anything.
How to take it.
Tirzepatide is an injection, given subcutaneously into the fat with a tiny insulin needle, once a week. It isn't an oral peptide in this form, so the injectable vial is what people run. The routine is below; for titration and timing, see the full guide.
Reconstitute the vial
Add bacteriostatic water down the side of the vial (a 30mg vial + 3mL = 10mg/mL). Let it dissolve. Swirl gently, don't shake.
Draw your dose
On a U-100 insulin syringe, pull to your unit mark. 2.5mg at 10mg/mL is 25 units (0.25mL). Use the calculator if you're unsure.
Pinch and inject
Swab with alcohol, pinch a bit of fat, insert at 45–90°, push slowly. The belly, thigh, or back of the upper arm all work. Take it the same day each week.
Rotate your sites
Move to a different spot each week so no area gets sore or lumpy. Store the vial in the fridge between doses.
The easiest spots are the belly (about 2 inches either side of the navel), the love handles, the front of the thigh, and the back of the upper arms. Rotate every injection.
Don't do the math, let the calculator do it.
This is Tirzepatide's typical setup, already worked out. Change any value and the draw updates instantly.
Typical Tirzepatide dose: 2.5 mg once a week to start, held for four weeks, then stepped up by 2.5 mg every four weeks as tolerated, up to a maximum of 15 mg once a week. Many people settle at 5 to 10 mg.
Cycling Tirzepatide.
Whether Tirzepatide is cycled at all, how long people run it, and the honest reasoning behind it.
Titrated up slowly to a maintenance dose, not cycled.
Tirzepatide is not really cycled the way recovery peptides are. People run it continuously while they are losing weight, slowly titrating the dose upward, then holding at a maintenance level once they hit their goal.
The honest catch is what happens when you stop. Appetite tends to come back, and a chunk of the lost weight often returns unless eating habits have genuinely changed. This is true of the approved drugs too, so plan for the long game rather than a quick fix.
- Titrate up slowly, four weeks per step, never more than 2.5 mg at a time.
- Hold at the lowest effective dose that keeps appetite in check, rather than always chasing the maximum.
- If you stop, taper rather than quit cold, and expect appetite to rebound. Whether and how to come off is a conversation for a licensed provider.
Want the full picture, on and off periods, the washout, stacking, and keeping your results? Read how peptide cycling works →
What's actually in the vial.
For one of these vendors we link the per-batch certificate itself, and the purity below is read straight off it. The rest link to the vendor's general lab-results page. We don't run the labs ourselves and we don't show a purity number unless it's printed on a certificate we link, so you can open the document and check it against the batch yourself.
| Vendor | Purity (per COA) | Batch / report | Certificate |
|---|---|---|---|
| Onyx Biolabs | 99.223% | TIR15-26032A | View COA ↗ |
| Spartan Peptides | see lab page | not shown | Lab results ↗ |
What people pair it with.
Tirzepatide is often run alone, since it is potent on its own. When people do stack it, the goal is usually to push appetite suppression further or to protect muscle while losing fat.
Triple-pathway appetite
Adds an amylin analogue on top of the GIP/GLP-1 base, so three appetite pathways are hit at once. The aim is deeper appetite suppression than either alone. Note this combo has no human trial behind it.
View stack →Fat loss with gut support
Some people add BPC-157 to ease the nausea and gut upset that come with GLP-1 dosing. The evidence for that is anecdotal, not clinical, so treat it as experimental.
View stack →Aggressive cut (advanced)
Running two incretin agonists together is something a few advanced users try for stalled weight loss. There is no safety data for stacking them, and the side-effect load roughly doubles. Most people should not.
View stack →In the same corner.
Other weight and metabolic peptides people compare against Tirzepatide.
Questions, answered straight.
Is Tirzepatide legal?
Tirzepatide is an FDA-approved medicine under the brand names Mounjaro and Zepbound, available by prescription. The research-grade vials we compare are a different thing: they are sold strictly for research use only, not as the approved drug, and are not for human use. WADA began monitoring tirzepatide in 2026, so competing athletes should check their sport's rules. Laws vary by country, so check what applies where you are.
What does research use only actually mean?
It means the product is sold for laboratory and research purposes, not as a supplement or medicine for people. These research vials have not been reviewed or approved for human use, even though the same molecule is approved as a prescription drug. We aggregate prices and public lab data so you can see the landscape; what you do with that is between you and a licensed provider.
How do I store it?
Keep the sealed, freeze-dried vial in the fridge and out of direct light. Once you mix it with bacteriostatic water, store it refrigerated and use it within about 28 days. Don't freeze a reconstituted vial.
How often do people dose it?
Once a week, every week, on the same day. People start at 2.5 mg, hold it four weeks, then step up by 2.5 mg every four weeks as tolerated, up to 15 mg. Use the calculator to turn your vial and dose into exact units.
Why titrate so slowly?
The nausea, and the gut side effects in general, are worst right after a dose increase. Climbing slowly, four weeks per step, gives your stomach time to adjust and keeps most of those effects mild. Jumping the dose is the fastest way to feel miserable.