Retatrutide

Retatrutide is a weight-loss shot you take once a week. It is made by the drug company Lilly.

Your gut makes hormones that tell your brain you are full. Most weight-loss shots copy one or two of these. Retatrutide copies three at once: GLP-1, GIP, and glucagon. Doctors call this a "triple agonist."

The third one, glucagon, is the new part. It seems to make your body burn a bit more energy. That may be why the weight-loss number is so big.

It is not FDA-approved. It is still in the final round of testing, called Phase 3 (the trial name is TRIUMPH). The only form you can buy today is research-only powder you mix yourself.

People use it for weight loss. It is the "next big number" drug after tirzepatide.

That is really the whole story right now. It is being studied for obesity, type 2 diabetes, and a liver condition. But none of that is approved use yet.

The early data looks strong, but it is not finished.

In the Phase 2 trial (338 people, published in 2023), people on the top dose lost about 24.2% of their body weight in 48 weeks. That is bigger than tirzepatide at the same point. For a 250-pound person, that is about 60 pounds.

The honest catch: the final, biggest trial (Phase 3) is still running. We do not have those results yet. So the early number is promising, but it is not the last word.

You take it as a small shot under the skin (subcutaneous), once a week.

Like the other shots in this family, you start low and go up slowly. Going up slowly is called titration. It gives your stomach time to adjust so you feel less sick.

There is no FDA-approved dose ladder, because the drug is not approved. People copy the trial doses, which climbed up to 12 mg a week. If you use RUO powder, get the molecule checked by a lab first (mass spec or HPLC) before you start dosing.

The common stuff

Expect the same stomach issues as the other GLP-1 shots: nausea, throwing up, diarrhea, or being backed up. They are worst right after a dose increase and ease over time. Smaller meals and going up slowly help.

The serious stuff

• It raised resting heart rate by about +7 bpm at the top dose, your heart working harder around the clock and more than the single-hormone shots push it. Skip it if you have an irregular heartbeat, uncontrolled high blood pressure, or heart disease.
• Like the others in this family, do not use it if you or a close family member has had a rare thyroid cancer (medullary thyroid carcinoma) or a condition called MEN-2.
• The biggest risk is the vial itself. RUO "retatrutide" has tested as tirzepatide or a mixed product, because this triple drug is hard to make cleanly.

Talk to a real doctor before you use this. We are not your doctor.

Here are the lanes, from safest to riskiest.

• Brand. None exists yet. Lilly's version is still in testing. FDA submission is expected in late 2026.
• Compounded. Some pharmacies sell it for $200 to $600 a month, but this lane is legally shaky. Retatrutide is not on the approved list, and the FDA sent warning letters in March 2026.
• Research-only (RUO). This is the main supply today, about $120 to $280 a month. Sold "for research only." Often below 95% pure because it is hard to make.
• Gray market. Overseas powder, $10 to $70 a month. Illegal to import for human use. Identity failures (it is really tirzepatide) are documented here too.

Key warning: because no approved version exists, even a lab report can only confirm it looks like the right peptide. It cannot prove it matches Lilly's real drug. Mislabeled vials are the recurring problem in this lane.