Retatrutide
made by Eli Lilly (in clinical trials)
Quick facts
- Researched for
- Weight loss, appetite control, less food noise, higher energy use and body changes
- Route or form
- Injection
- Evidence so far
- Human trials show weight loss and better blood sugar; long-term heart data are still missing.
- Not established
- It is still in trials; forum comparisons with semaglutide or tirzepatide are not controlled studies.
- Commonly researched
- Starts at 2 mg, once weekly, then steps upPractitionerSee every range
- Where to get it
- At our partner, US Precision Peptides.Go to Next step
By the Learn Peptides editorial team · Updated · How We Research
What people are researching it for
People are researching retatrutide for weight loss, appetite control, less , higher energy use, and body changes.
Three pathways. More possibilities.
Retatrutide is an investigational research peptide...
- What is Retatrutide?
- Not written out in this text version.
- How does it work?
- Receptors: GLP-1, GIP, and glucagon
- Common research use cases
- ...those with obesity, type 2 diabetes, and cardiovascular risk factors.
- What research shows
- Up to 28.3% mean weight loss at 80 weeks (Phase 3 TRIUMPH-1, highest studied dose)
- Up to 82.4% reduction in liver fat at 24 weeks (in participants with fatty liver disease)
- Improvements in cardiometabolic markers (including A1C, lipids, and liver enzymes)
- Most common side effects in trials were gastrointestinal (nausea, diarrhea, vomiting, constipation), increased heart rate, and skin sensitivity. Results may vary based on individual response, dose, and study population.
- What users report
- Increased resting heart rate
- Skin sensitivity (“sunburn-like” feeling)
- Varied energy effects (more energy for some, fatigue for others)
- Mixed reports on strength and exercise performance
- Key takeaway
- It's not a magic solution, and experiences vary widely. Use only high-quality peptides, follow a research-focused approach, and set realistic expectations.
- The bottom line
- ...but it remains investigational, and individual results can vary.
Reasons people look into Retatrutide. An interest is not a promise that it works.
- Weight loss & metabolic
- Body composition & performance
People compare its hunger control with semaglutide or tirzepatide, and watch energy and fat loss.
Community reports
Community discussion often compares appetite control with semaglutide or tirzepatide while watching for differences in warmth, energy, and fat loss.
Community reports
People on retatrutide describe some of the strongest appetite and suppression of the three drugs, and several say it keeps working well past the point where semaglutide or tirzepatide leveled off for them. Reports also include reduced alcohol interest, flattened mood or lower sex drive, and a real need to actively manage water and electrolytes to avoid feeling awful.
Human trials show large weight loss; it acts on 3 hormone signals tied to appetite.
Human trials have shown large weight-loss effects. Retatrutide acts on three hormone involved in appetite and metabolism.
The newest of the three -class weight-loss drugs: it acts on a third hormone that the other two don't touch.
What this is based on
- Human researchStudied in people for this or a related question.
- Community reportsWhat people describe noticing. Not proof of cause.
- Industry perspectiveCommentary from practitioners and the industry, based on experience. Not a study.
- Learn Peptides explanationOur own plain-English summary of the sources. It is not a source itself.
It is still in trials; forum comparisons with semaglutide or tirzepatide are not controlled studies.
It is still an investigational drug. Community comparisons with semaglutide or tirzepatide are not controlled head-to-head studies.
Safety notes
Tested in people. How many took part, for how long, and who they were still matter.
- You have trouble breathing or wheezing, or your face, lips, tongue or throat swell.
- You get hives away from the injection site, or feel severely dizzy or faint.
For these signs, call 911 or your local emergency number.
- You have severe stomach pain that does not go away, with or without vomiting. It may spread to your back. Stop it and get medical help now. The semaglutide and tirzepatide labels list this as a sign of pancreatitis, and retatrutide is in the same drug class. Wegovy label and Medication Guide (FDA, via DailyMed) (opens in a new tab) Zepbound label and Medication Guide (FDA, via DailyMed) (opens in a new tab)
- You notice a lump or swelling in your neck, hoarseness, trouble swallowing or shortness of breath. The semaglutide and tirzepatide labels list these as possible signs of thyroid cancer, and retatrutide is in the same drug class. Wegovy label and Medication Guide (FDA, via DailyMed) (opens in a new tab) Zepbound label and Medication Guide (FDA, via DailyMed) (opens in a new tab)
- You have pain in your upper stomach, a fever, yellow skin or eyes, or clay-colored stools. The semaglutide and tirzepatide labels list these as possible signs of gallbladder problems, and retatrutide is in the same drug class. Wegovy label and Medication Guide (FDA, via DailyMed) (opens in a new tab) Zepbound label and Medication Guide (FDA, via DailyMed) (opens in a new tab)
- You also take insulin or other blood-sugar medicine and feel dizzy, shaky, sweaty, confused or drowsy, or your heart beats fast. The semaglutide and tirzepatide labels list these as signs of low blood sugar, and retatrutide is in the same drug class. Wegovy label and Medication Guide (FDA, via DailyMed) (opens in a new tab) Zepbound label and Medication Guide (FDA, via DailyMed) (opens in a new tab)
- Redness spreads, or heat, swelling or pain keeps growing where you injected.
- A lump keeps growing or does not go away, or you see pus or red streaks.
- You have a fever or chills, or feel sick all over.
- Medullary thyroid cancer or MEN2 (you or your family). It is in the same drug class as semaglutide and tirzepatide, whose labels carry a boxed warning for medullary thyroid cancer and MEN2.
- Pancreatitis or gallbladder disease. It is in the same drug class as semaglutide and tirzepatide, whose labels warn about pancreatitis and gallbladder problems. With a history of either, this is one to talk through with your doctor first.
- Diabetes, or you take insulin or blood-sugar medicine. Combined with insulin or other blood-sugar medicine it can push blood sugar too low. Your doctor may need to adjust those medicines.
- Sort out hormones (testosterone, thyroid, cortisol) before starting; do not use it as a substitute for hormone optimization. Industry perspective
- Resting heart rate reliably rises, peaking around week 24. The cited commentary describes adding 5 to 10 g of taurine a day to help manage it. Industry perspective
- In the practitioner's figures, about 27% get nausea, 23% diarrhea and 18% vomiting. Stepping up every 4 or more weeks, not every 2, helps reduce this. Industry perspective
- Suppresses thirst too, so dehydration risk is high and can worsen other side effects. Industry perspective
- A skin-sensation side effect (tingling/burning with nothing visible) occurs in up to 1 in 5 people at 12 . Industry perspective
- Can drop blood pressure significantly, especially risky for lean people with already-normal blood pressure. Industry perspective
- Losing significant weight without enough protein and resistance training causes disproportionate muscle loss. Industry perspective
- Do not stop suddenly after a high dose. Step down first. Industry perspective
Questions to bring to your doctor
Only for the conditions this page cautions about. Bring this page with you.
- I or someone in my family has had medullary thyroid cancer or MEN2. Does that rule out retatrutide for me?
- I have had pancreatitis or gallbladder problems. Is retatrutide a concern for me?
- Would my insulin or blood-sugar medicine need to change if I used retatrutide?
Shows practitioner schedules and the amounts one human trial used, each with its source.
Commonly researched ranges, and how they were measured.
Commonly researched range for Retatrutide
Starting dose
2 mg
once weekly · Injection
Practitioner
How the dose steps up
Each schedule comes from one source, shown in order. Do not mix steps from different sources.
Practitioner schedule
- Step 1 of 4: Weeks 1 to 42 mg once weekly
- Step 2 of 4: Weeks 5 to 84 mg once weekly, if tolerated and needed
- Step 3 of 4: Weeks 9 to 126 mg once weekly, if needed
- Step 4 of 4: Weeks 13 to 178 mg once weekly, if needed
The practitioner treats 8 mg as the most that works for most people, though the trial allowed up to 12 mg.
Phase 2 trial (NEJM)
- Step 1 of 3: Start2 to 4 mg once weekly
- Step 2 of 3: ThenSteps up every 4 weeks, for up to 12 weeks
- Step 3 of 3: Target4 to 12 mg once weekly
These are the amounts the trial used, not dosing instructions for other products. One trial group took 1 mg with no stepping up.
All 9 ranges in our record
Each one is labeled with where it comes from. Some are parts of the step-up schedules above. Do not mix steps from different sources.
Standard titration, weeks 1-8 (starting dose)
Practitioner- Amount per dose
- 2 to 4 mg
- How often
- Once weekly
- Typical schedule
- Weeks 1-4 at 2 mg, then weeks 5-8 at 4 mg if tolerated/needed
- Route
- Injection
Standard titration, weeks 9-17 (ceiling)
Practitioner- Amount per dose
- 6 to 8 mg
- How often
- Once weekly
- Typical schedule
- Weeks 9-12 at 6 mg, then weeks 13-17 at 8 mg (trial allowed up to 12 mg, but 8 mg is the practitioner's stated maximum effective dose for most people)
- Route
- Injection
Long-term lower-burden maintenance
Practitioner- Amount per dose
- 4 mg
- How often
- Once weekly
- Typical schedule
- Long-term, after initial titration
- Route
- Injection
Lean/longevity starting dose
Practitioner- Amount per dose
- 1 mg
- How often
- Once weekly
- Typical schedule
- Hold 4 weeks then reassess
- Route
- Injection
Lean/longevity working dose
Practitioner- Amount per dose
- 2 to 4 mg
- How often
- Weekly or twice weekly
- Typical schedule
- Not stated
- Route
- Injection
Longevity maintenance taper
Practitioner- Amount per dose
- 1 to 2 mg
- How often
- Once or twice weekly
- Typical schedule
- Indefinite
- Route
- Injection
Initial dose (for 4 mg+ target arms)
StudyNEJM Phase 2 trial- Amount per dose
- 2 to 4 mg
- How often
- Once weekly
- Typical schedule
- Gradual dose escalation every 4 weeks for up to 12 weeks to reach target dose
- Route
- Injection
This is the amount a study used. It is not a dosing instruction for other products.
Target dose, low/no-titration arm
StudyNEJM Phase 2 trial- Amount per dose
- 1 mg
- How often
- Once weekly
- Typical schedule
- Not stated
- Route
- Injection
This is the amount a study used. It is not a dosing instruction for other products.
Target dose, escalated arms
StudyNEJM Phase 2 trial- Amount per dose
- 4 to 12 mg
- How often
- Once weekly
- Typical schedule
- Reached via gradual escalation - see the initial-dose convention above
- Route
- Injection
This is the amount a study used. It is not a dosing instruction for other products.
These ranges were last reviewed Sep 2026.
Check your syringe math with your own numbers.
An Eli Lilly drug still in clinical trials that acts on 3 hormone signals.
Retatrutide is made by Eli Lilly and is still in . It activates three separate hormone at once instead of one or two. In a mid-size human trial for obesity, people lost a substantial amount of weight. It's given as an injection.
Three weekly injections studied for weight loss. They act on 1, 2 or 3 hormone signals. Here is what people report, what trials show and what is still unknown.
Next step
About product links
Purchases at US Precision Peptides help keep Learn Peptides free.