Tirzepatide

Tirzepatide is a medicine you inject once a week. You may know it by its brand names, Mounjaro and Zepbound.

Your gut makes natural hormones that tell your brain you are full. Tirzepatide copies two of those hormones at the same time. They are called GLP-1 and GIP. It turns up that "I am full" signal. So you feel hungry less often, you eat less, and you lose weight.

It is FDA-approved. That means the U.S. government checked it in large studies and agreed it is safe and that it works.

Most people take tirzepatide to lose weight.

Doctors also give it to people with type 2 diabetes, because it helps keep blood sugar down.

It is not a recovery or anti-aging peptide. If that is what you are after, this is not the one.

Yes. This is one of the best-studied weight-loss drugs we have.

In the biggest study (called SURMOUNT-1), people lost about 22.5% of their body weight in about a year and a half on the top dose. That is the largest weight loss ever seen in a big trial like this. For someone who weighs 250 pounds, that is around 56 pounds.

One honest catch: the weight comes back if you stop. When people quit, a lot of the weight returns. Most people who do well either stay on it long-term, or come off slowly with a real plan.

You take it as a small shot under the skin once a week. This kind of shot is called a subcutaneous shot. People usually do it in the belly, the thigh, or the upper arm.

You start at a low dose and go up slowly. Going up slowly is called titration. Starting low gives your stomach time to get used to it, so you feel less sick.

The usual ladder is 2.5 → 5 → 7.5 → 10 → 12.5 → 15 mg, moving up about every 4 weeks.

15 mg is the top of the ladder, not the start. Lots of people lose plenty of weight without ever reaching the top. If a dose is working and you feel fine, there is no rush to climb higher.

The common stuff

Most side effects are stomach problems: feeling sick (nausea), throwing up, diarrhea, or being backed up (constipation). They are usually worst right after you go up a dose, and they ease over time. Smaller meals and going up slowly help a lot.

The serious stuff

• It carries the FDA's strongest warning (a "black box") for a rare thyroid cancer. Do not use it if you or a close family member has had this cancer, or a condition called MEN-2.
• Birth control pills may not work as well after you raise your dose. Use a backup method (like condoms) for 4 weeks after each dose bump.
• Losing weight fast can mean losing muscle too. To protect your muscle, eat plenty of protein and do some strength exercise while you are on it.

If anything feels wrong, talk to a real doctor. We are not your doctor.

There are a few ways people get tirzepatide. Here they are from safest to riskiest.

• Brand (Mounjaro / Zepbound). A real pharmacy product you get with a prescription. Safest. Lilly's own service (LillyDirect) sells cash vials for about $300–$450 a month.
• Compounded. Made by special pharmacies. This used to be a cheaper middle option, but most of the big ones were shut down in 2025, so it is getting hard to find.
• Research-only (RUO) or the gray market. Cheap, but sold "for research only," with no promise of what is really in the vial. You mix it yourself. This is the highest risk.

One scam to know about: stay away from vials labeled "tirzepatide + B12" or "tirzepatide blend." That mix is a common way sellers water down the real drug, so you get less than you paid for. The cleanest product is tirzepatide on its own. If you buy from a research vendor, ask for a COA, a lab report that shows what is really in the vial.