Retatrutide Results: What Changed for People in the Trials?

What do the main results mean for you?

The scale may show the first change. Phase 1 came before the two Phase 2 reports. In Phase 2, 338 adults with obesity took part for 48 weeks. At 12 mg, their weight fell 24.2% on average. The placebo group got shots with no drug and lost 2.1%. No approved drug of this kind had reached that result in a Phase 2 trial.

The strong result came with more trouble. At the top test amount, nausea affected almost half the group and 18% left. Resting pulse rose as the amount rose. We don't know the long-term risks because Phase 3 is still gathering facts.

This page brings Phase 1b and two Phase 2 reports together. They cover weight, blood sugar, liver fat, and bad effects. Each number points to a source. For outside reports from people using research-marked material, see Retatrutide effects.

When you read the average loss, remember that some people lost more and some lost less, and the trial can't tell which result would be yours outside its care.

Which Phase 1b results matter most?

The trial followed 72 adults with type 2 diabetes for 12 weeks ^[4]. Staff raised test amounts in steps. People got one shot under the skin each week.

• At the top amount, people lost more weight than the placebo group. A 90% math check backed the group result, but it can't predict one person's loss.
• At 3 mg, blood sugar before food fell more than with placebo.
• Half the drug left in about 6 days.
• The weekly shot under the skin was the only way tested with blood checks.

Health problems affected 63%. Most were stomach trouble. The researchers found the safety signs acceptable at each amount. No one had severe low blood sugar.

This work found that a weekly shot and slow increases could be used in Phase 2.

How much weight did people with obesity lose in Phase 2?

The trial followed 338 adults with obesity for 48 weeks ^[1]. They scored at least 30 on the height-and-weight chart, or 27 with another health problem. Men made up 51.8%. The report writes its groups as 1/4/8/12 mg, meaning separate amounts. Chance set the groups. You can compare each line below.

Average weight change at 48 weeks

Health problems:

• Nausea rose from about 23% at 1 mg to 45% at 12 mg.
• Vomiting affected 12–28%.
• Diarrhea affected 12–20%.
• Constipation affected 12–22%.
• Health problems made 3% leave at 1 mg and 18% leave at 12 mg.
• About 8% had a reaction where the shot went in.
• Pulse rose with the amount. Near 24 weeks, the top groups averaged about 5–7 extra beats per minute.
• No severe low blood sugar was reported.
• No one died.

What changed for people with type 2 diabetes in Phase 2?

The trial followed 281 adults with type 2 diabetes for 36 weeks ^[2]. Their blood test of usual sugar began at 7.0–10.5%. Chance placed them in groups getting weekly drug shots, placebo, or another drug. Trial staff raised the amount in steps. The 12 mg group received the highest test amount.

At 12 mg compared with placebo:

• At 24 weeks, the blood test fell 2.02% against 0.01%. It reflects about a 3-month span of blood sugar.
• At 36 weeks, body weight fell 16.94% against 3.00%.

About 35% had mild to moderate stomach problems. No one died or had severe low blood sugar. People already using insulin needed less during the trial. Retatrutide plus insulin shots could make blood sugar fall too low ^[2].

How much did liver fat fall?

This 48-week study followed 98 people with obesity or excess weight ^[5]. They had fatty liver. Each started with at least 10% liver fat and no diabetes. MRI scans measured what share of the liver was fat, with no cut or needle.

Change in liver fat at 24 weeks:

Liver fat below 5% is called normal. At 24 weeks, 86% of people at 12 mg reached that mark. The drop held through 48 weeks. Liver fat at 12 mg was still far below the start.

What must Phase 3 trials still tell us?

Phase 3 trials were still running in mid-2026. No Phase 3 report had said how well the drug works. Long-term safety is also still open. Phase 3 has four main questions, listed on ClinicalTrials.gov:

• Weight trial 1: How much weight changes in people with obesity.
• Weight trial 2: What happens in people with obesity and diabetes.
• Heart health: What happens to the heart, and how retatrutide compares with tirzepatide.
• Kidney health: What happens when long-term disease has already harmed the kidneys.

Trial 1 covers obesity alone, while trial 2 adds diabetes. Reviews say Phase 3 weight loss may come near the amount seen after bariatric surgery ^[8]. A 2025 review said these trials may find the upper reach of weight loss from a drug ^[7]. That isn't a result yet.

A 2025 review discussed what similar drugs may do to the kidneys and heart ^[11]. A 2026 review covered drugs that copy several food-linked hormones ^[13]. The Retatrutide research page explains what retatrutide may do inside the body.