Phase 1 and Phase 2 studies tested retatrutide dosage.

Retatrutide study amounts are not directions

Retatrutide remains under study. No approved sale exists. No drug agency has set an approved dose. The amounts below come from published studies.

Study doctors watched each person. They checked blood and asked about side effects. A doctor could lower or stop an amount. An unchecked bottle is different. Words on a label can't replace a known drug and clinic care.

These amounts are not home-use steps. The Retatrutide research page tells what happened at each amount.

Your care can't come from a study table.

Retatrutide dosage varied across four studies

Early studies gave a shot beneath the skin each week. The smallest amount was 0.5 mg. The largest was 12 mg.

First study, 72 adults, 12 weeks. The study used 0.5, 1.5, 3, 3/6, and 3/6/9/12 mg. The slashes mark planned increases. They do not mean mixed amounts. The top group moved through 3, 6, 9, and 12 mg during those 12 weeks ^[4].

Phase 2 obesity study, 338 adults, 48 weeks. Phase 2 was an early test of benefit and harm. Groups worked toward 1, 4, 8, or 12 mg each week. Doctors started low, then increased the amount. The slower rise sought to ease stomach trouble ^[1].

Phase 2 diabetes study, 281 adults, 36 weeks. Phase 2 amounts rose from 0.5 mg to 12 mg. Doctors again raised them slowly to ease stomach trouble ^[2].

Phase 2 fatty liver study, 98 adults, 48 weeks. Weekly amounts were 1, 4, 8, and 12 mg ^[5].

These amounts describe research. They aren't advice.

Retatrutide half life explains the weekly study shots

The first small study found a retatrutide half life of about 6 days ^[4]. Half life tells how long half the drug remains in blood. That finding helped support one shot in each 7-day span. Every Phase 2 study used weekly shots.

An added part binds retatrutide to albumin. Albumin is a common blood protein. The bond slows the drug's exit. Similar weight drugs use this approach.

With weekly shots, the amount in blood rises for a while. It may take 4-5 half lives to level off. That means about 3-4 weeks. By then, the blood amount may be 4-5 times the amount after the first shot. Study doctors raised doses while the drug built up. The slow rise helped limit stomach and bowel trouble.

Your kidneys and other drugs may change this timing.

Retatrutide side effects increased at larger amounts

GLP-1 is a gut hormone that curbs hunger. Across Phase 2 studies of drugs copying it, stomach and bowel trouble rose with the dose. Phase 2 gives an early test of benefit and harm. Nausea, diarrhea, vomiting, and constipation were common. At the top dose, 18% left the obesity study ^[1].

Retatrutide keeps food in the stomach longer. That can curb hunger. It can also bring nausea. Larger amounts slowed the gut more.

The pulse rose more at larger amounts. At the top doses, the average rise was about 5-7 beats a minute. It peaked near 24 weeks ^[1]. The hormone tied to liver fat can also speed the heart.

In the diabetes study, doctors lowered the insulin amount for insulin users. Retatrutide also helps the body release insulin ^[2]. A doctor and blood tests kept watch.

Tell your doctor if your resting pulse speeds up.

Retatrutide cost has not been announced

Retatrutide isn't an approved prescription drug. The maker hasn't set a store price. No standard insurance price or coverage exists.

Phase 3 study drugs aren't sold like approved drugs. In some cases, the FDA lets a person seek an unapproved drug outside a study. No public retatrutide program had been announced.

Research sellers set their own prices. Those prices don't cover a drug checked by the FDA. A seller price does not prove the bottle is safe.

A price today isn't an approved price.

How to reconstitute retatrutide has no safe public answer

Retatrutide has no approved drug form. The FDA and maker haven't issued mixing steps for use outside a trial.

In Phase 2 studies, people got retatrutide from a pre-filled pen. They didn't mix dry powder with water. Study papers name the liquid and other parts used by researchers. No public drug label gives home steps.

Online steps for research bottles have no approved standard. No sound public source gives those steps. An unchecked bottle could contain another drug, wrong strength, or germs.

An unknown bottle gives you no sound starting point.

Retatrutide availability does not reach pharmacy shelves

Pharmacy appears in the site name. Retatrutide isn't stocked by a pharmacy. A pharmacist can't lawfully give it to you. Neither can a pharmacy that mixes drugs for people or clinics. The drug is still in Phase 3 trials.

In 2025, the FDA warned these mixing pharmacies and research sellers. The letters cited federal drug law. Current rules don't let either type of special mixing pharmacy make retatrutide.

No pharmacy can offer you an approved prescription. Approved retatrutide isn't on a pharmacy shelf.

You won't find it behind a drug counter.