What retatrutide dosage did Phase 1, 2, and 3 test?
The first round checked safety, the middle round tested results, and the final round uses larger groups. Study doctors raised set amounts with care.
What do the retatrutide amounts mean for you?
The amounts below are only those used in human studies through 2026. They don’t tell what would fit your health or your medicines.
No country has approved retatrutide for people. Doctors have set no safe amount outside a watched human study.
Each section says how much the studies used, how the drug entered the body, and how long the test ran. Those facts aren’t personal directions.
Which retatrutide dosage did the Phase 2 weight study use?
In 2023, the 48-week Phase 2 weight study used 1 milligram, 4 milligrams, 8 milligrams, or 12 milligrams each week; milligrams measure drug weight [1]. Each shot went into the fatty layer below the skin.
Doctors began with less drug and moved upward over several weeks to ease stomach trouble. At 12 milligrams each week, average weight fell 24.2% over 48 weeks.
Every amount was given once a week in this way. Human tests haven’t tried another way to give the drug.
Which retatrutide dosage did the Phase 2 type 2 diabetes study use?
During 2023, the Phase 2 type 2 diabetes study raised the weekly amount from 0.5 milligrams to 12 milligrams over 36 weeks [2]. The steps were 0.5, 1.5, 3, 6, and then 12 milligrams.
The slow rise gave each person’s body time to adjust. Larger amounts brought larger drops in the long-term blood-sugar test.
At 12 milligrams each week, the blood reading fell 2.02% by 24 weeks. Weight fell 16.94% by 36 weeks.
What does retatrutide half life mean?
Retatrutide’s half-life is about 6 days [4]. This means your body still holds about half of the drug after that time.
In 2022, the first human test found this 6-day span. The finding helps explain why later studies used weekly shots.
Several weekly shots were needed before the blood level became steady. Weight and blood-sugar changes built later, over months rather than days.
Scientists altered one part so retatrutide travels with albumin, a common blood protein. Traveling with albumin lets the body clear the drug much more slowly than a natural hormone.
Why can’t powder become tested retatrutide at home?
Human studies used retatrutide made under strict drug rules. They didn’t use powder mixed at home.
Powder sold outside a study has no approved mixing method or sure germ-free standard. A vial labeled “research retatrutide” may not match what researchers gave to people.
The powder may have the wrong drug or strength. It may also contain germs or poisons left by germs.
Storage facts for the study drug apply only to that drug. They give no sound handling answer for powder with unknown contents.
What is the current retatrutide availability?
No pharmacy sold retatrutide as medicine anywhere by mid-2026. Eli Lilly was still testing it in Phase 3.
Neither a doctor nor a pharmacy can provide it by prescription. A listed human study is the only sound place where a person may receive the test drug with health checks.
Products sold outside studies as “research” retatrutide have no sure proof of contents or purity. In 2025, the FDA sent warning notices to over 50 sellers of such products.
When might retatrutide become available?
No one knows. Eli Lilly must finish its Phase 3 tests and then ask drug reviewers for permission to sell retatrutide.
As of mid-2026, several Phase 3 studies still had work left. Results about the heart and kidneys were also still due.
People outside the company have guessed at a 2026-2027 filing, but no public result supports that date. Lilly hasn’t announced when it will ask for review.
Eli Lilly reports company news. ClinicalTrials.gov lists whether each study is still running, but neither source gives an approval date.
What might retatrutide cost?
Retatrutide has no sale price because it isn’t approved. Any future price would depend on its approved use, insurance, the market, and Eli Lilly’s plans.
For comparison only, approved drugs such as tirzepatide can list for $900-$1,400 a month in the United States without insurance. That range shows what related medicines cost now; it doesn’t predict a retatrutide price.
Retatrutide could cost more, less, or about the same. No firm answer exists, and this site doesn’t link to sellers.