Which retatrutide dosage amounts were used in studies?
Learn what doctors gave, how they gave each shot, and why the numbers don't provide an amount for you.
Why show study amounts when retatrutide has no approved dose?
No agency has approved retatrutide, so the public has no approved dose. Here you'll only find the amounts that doctors used in studies and the way they gave each shot. The study amounts don't tell you what to do on your own, because trained staff knew the drug, checked each shot, watched for harm, and changed care quickly if someone became ill.
The staff used a clean product with a known strength. They checked each person's health and stepped in when needed. Material from beyond a study doesn't give you those safeguards.
The amounts help you match a result with the right study. They also show what the larger Phase 3 stage builds on. Every finished study used one weekly shot in the fatty layer beneath the skin.
Which retatrutide dosage amounts did doctors actually test?
The opening human study: Adults with type 2 diabetes received 0.5, 1.5, or 3 mg. Later amounts reached 12 mg. Staff gave weekly shots for 12 weeks [4] and watched for early changes and harm.
The Phase 2 obesity study: Phase 2 means the mid-sized testing stage. Weekly amounts were 1, 4, 8, and 12 mg for 48 weeks [1]. No one began at the largest amount, because staff used small increases to make stomach and bowel problems easier to bear.
The Phase 2 diabetes study: Weekly amounts ran from 0.5 to 12 mg for 36 weeks [2]. Here too, the amount went up step by step. Doctors watched blood sugar and other health signs throughout the study.
Across these mid-sized tests, larger amounts brought more average weight loss and more side effects. In the obesity study, average weight fell −24.2% after 48 weeks in the 12 mg group. After 36 weeks, it fell −16.94% in the diabetes study [1][2]. Gut problems were the main reason among those who left the highest group.
The large Phase 3 studies hadn't named the amounts they would use. Phase 2 findings still don't create a dose outside research. No published number can fill that gap.
Why did retatrutide studies give one shot each week?
That early human test found a 6-day span before the blood amount fell by half [4]. Doctors call that time the half-life. Enough remained to support the weekly plan used in later studies.
Retatrutide is a 39-amino-acid chain, meaning a chain of linked protein pieces. The makers added a small fat-like tail to one end. That tail grips albumin, one of the proteins that carries things in your blood, and helps the drug remain longer.
The blood finding accounts for the weekly shots used in studies. It doesn't name a safe amount or plan for you. Your health and other medicines could change the risk, and no schedule has been approved.
Where did doctors put the retatrutide shots?
Every finished study used a weekly shot placed beneath the skin, in body fat. No study has reported a pill, vein drip, or nose spray. Doctors used the belly, a thigh, or an upper arm.
Retatrutide can slow how fast food leaves the stomach [11]. That may help you feel full sooner. It may also bring nausea or a full feeling that lasts too long.
How to reconstitute retatrutide: has any mixing method been approved?
No method for mixing retatrutide powder into a shot has been approved. The drug has never had an FDA label. Eli Lilly supplied a clean, ready-made drug for the studies.
The mid-sized Phase 2 and larger Phase 3 studies used known supplies, not research powder from the internet. A seller's label can't prove what is inside, how strong it is, or whether it carries germs. People in the studies received prepared shots and did no mixing themselves.
You won't find mixing steps here. Those directions would go far beyond what doctors tested. No approved form, storage rule, or mixing standard exists outside a study.
When could retatrutide be available, and what must happen first?
Retatrutide is not commercially available. It has not been approved by the FDA or any other regulatory agency. It is available only within the context of active clinical trials.
That boundary matters when discussing retatrutide: any lawful prescription pathway, including the Promise Peptides telehealth route at mypromise.com, requires a clinician’s review, while this investigational compound remains available only within clinical trials.
A gray market exists for retatrutide sold under a "research purposes" label. The FDA issued over 50 warning letters to retatrutide vendors in 2025 citing Federal FD&C Act violations. This site does not link to, endorse, or describe vendors. The safety and efficacy data on this site were all generated in the context of clinical trials with confirmed, GMP-grade material — not in the context of gray-market compounds.
When will retatrutide be available? If the TRIUMPH Phase 3 program meets its endpoints and Eli Lilly files for regulatory approval, and if the FDA approves the application, retatrutide could potentially become available as a prescription medicine. No timeline for approval exists as of mid-2026, and approval is not guaranteed.