Retatrutide
Also called LY3437943, triple agonist, triple G, retra
The one that works on three hormones at once
Retatrutide is an experimental weekly weight-loss injection from Eli Lilly. It copies three hormones your body already makes, two that tell your brain you are full and one that raises the energy you burn at rest. In its main trial people lost an average of 24.2% of their body weight over 48 weeks. It is not approved yet.
Retatrutide is a weekly injection being tested for weight loss. Most drugs in this family copy one or two of your gut hormones to blunt appetite. Retatrutide copies three, and the third one also nudges up the energy you burn while resting, so weight comes off through burning a little more as well as eating a little less. In its main trial people lost an average of 24.2% of their body weight in 48 weeks, and the weight was still dropping when the trial ended. It is still being tested and is not approved anywhere.
- Half-life
- About 6 days, which is what makes weekly dosing possible
- Route
- Weekly injection under the skin
- Typical dose
- Trial doses ran from 1 mg to 12 mg weekly, started low and raised gradually
- Availability
- Research-only
Human trials published, with more underway
160 papers · 7 clinical trials
What people use Retatrutide for
Reported uses, roughly in order of how often they are the reason someone goes looking. Whether it works for any of them is a separate question, answered under each one.
- Weight loss, at the top end of what drugs can do
- This is the one people are waiting for. In its Phase 2 trial the highest dose took people down around 24% over 48 weeks, which is more than any other drug in this class has managed and closer to surgery territory than to Ozempic.
- Fatty liver
- The glucagon part of it works directly on the liver, and liver fat dropped sharply in the trials. That is a separate benefit from simply being lighter.
Mechanism of Action
How Retatrutide works
Your gut releases hormones after you eat. They are the reason a meal eventually makes you feel done. Retatrutide copies three of them at once.
- The fullness signal tells your brain you have eaten enough and slows how fast your stomach empties, so meals stay satisfying for longer. This is the same signal Ozempic uses.
- The insulin-sensitivity signal helps your body handle sugar and fat more efficiently, and adds a second, separate nudge toward feeling full. This is what Mounjaro added on top.
- The energy-burning signal is what makes retatrutide different. It raises the amount of energy you burn at rest and pushes your liver to use up its stored fat. Nothing else in this class does it.
The practical difference: the other drugs mostly work by making you eat less. Retatrutide does that too, and then also raises what you burn. That is why its trial numbers came in higher, and why the liver-fat results stood out.
Retatrutide dosage: what each dose produced
Retatrutide is not approved. No regulator has cleared it, so there is no established dose and nothing below is a recommendation. It is a record of what one published trial ran.
Retatrutide is not approved, so there is no prescribed dose. What exists is the trial. Everyone started low and stepped up gradually over about 12 weeks, which is how the higher doses were made tolerable. Here is what each group was given and what they weighed 48 weeks later.
| Dose | How it was given | Average body-weight change at 48 weeks |
|---|---|---|
| Placebo | Weekly injection | −2.1% |
| 1 mg | Weekly, no step-up | −8.7% |
| 4 mg | Weekly, stepped up over 12 weeksTwo groups reached 4 mg by different routes, one starting at 2 mg and one at 4 mg. The trial reports them as one figure. | −17.1% |
| 8 mg | Weekly, stepped up over 12 weeksTwo groups reached 8 mg by different routes, one starting at 2 mg and one at 4 mg. The trial reports them as one figure. | −22.8% |
| 12 mg | Weekly, stepped up over 12 weeks from 2 mgPeople in this group were still losing weight when the trial stopped, so nobody knows where it would have levelled off. | −24.2% |
Least-squares mean change in body weight from the start of the trial to 48 weeks. This is an adjusted average, not a raw one.
Source: Jastreboff et al., Triple-Hormone-Receptor Agonist Retatrutide for Obesity, a Phase 2 Trial, New England Journal of Medicine, 2023. 338 people, randomised across seven groups.
Converting one of these into syringe units? The calculator below opens on this compound.
These are group averages. Two people on the same dose did not get the same result, and the genes that build these receptors are one reason why. That is the part a DNA report can speak to. It is not medical advice, and any decision belongs with a qualified clinician.
Retatrutide dosage calculator
Opens at 1 mg, from the doses reported for Retatrutide. Change any box to match your own vial. It works out where to pull the plunger to.
How much is in the vial?
Printed on the label, in milligrams
How much water did you add?
Bacteriostatic water, in millilitres
What dose are you taking?
The dose you already intend to use
Which syringe?
Barrel size, printed on the wrapper
Draw to
20 units
on a 0.5 mL insulin syringe (0.2 mL)
- Strength once mixed
- 5 mg/mL
- Doses in the vial
- 10
10 mg in 2 mL makes 5 mg/mL. A 1 mg dose is 0.2 mL of that, which is 20 units.
Want a rounder number? Adding 1 mL instead would put this dose at exactly 10 units, which is easier to draw accurately.
This is arithmetic, not advice. It converts a dose you already have into a mark on a syringe. It does not tell you what dose to take, and Retatrutide is not prescribed by us. Dosing belongs with a qualified clinician.
Retatrutide side effects: what people reported
Most of what people reported was stomach-related, and most of it showed up while the dose was being stepped up rather than once they had settled at their dose.
Most commonly reported
- Nausea
- Diarrhoea
- Vomiting
- Constipation
Worth knowing about
- Heart rate went up on higher doses. It peaked around the 24-week mark and then came back down over the rest of the trial.
Not yet answered
- What happens past 48 weeks, and what happens if you stop
- How it behaves in people who were not part of this trial group
Dose matters. Reports were more frequent on higher doses, and eased once the step-up period was over.
Source: Jastreboff et al., New England Journal of Medicine, 2023. The larger Phase 3 trials have not reported yet, so the long-term picture is still being filled in. This is a summary of published findings, not a complete safety profile and not medical advice. Retatrutide should only be considered with a qualified clinician who knows your history.
Your Genetics & Retatrutide
The genes involved in how Retatrutide works
Retatrutide works through the receptors these genes build, and the genes vary from person to person. Researchers have linked some of that variation to differences in how people respond. A DNA report tells you which versions you carry.
This is the gene for the receptor that handles retatrutide's third hormone, the one that raises what you burn at rest. It is the part of retatrutide that no other drug in this class has, so this gene is worth looking at here and is beside the point for Ozempic or Mounjaro. Studied for its association with how strongly that signal comes through.
GIPR · ••
The Glu354Gln variant is associated with differences in how this receptor is made and how strongly it responds. Retatrutide shares this signal with Mounjaro, so it relates to part of the appetite and blood-sugar effect rather than the whole thing.
GLP1R · ••
The Gly168Ser variant sits in the receptor for the main fullness hormone and has been associated with differences in how much weight people lose on drugs in this family. It relates to the part of retatrutide that overlaps with Ozempic.
TCF7L2 · ••
The most common inherited variant linked to type 2 diabetes risk. People carrying the T version tend to release less insulin after eating. It is included because it relates to the blood-sugar side of how these drugs behave, not to how much weight you lose.
The dots after each gene are where your own result goes. Your report fills them in with the two letters you carry at that position.
Which variants do you carry?
Upload your DNA data, or get tested through our partner, to find out.
Commonly combined with
What Retatrutide is most often paired with, and why:
BPC-157
GI Protection StackModerate EvidenceBody Protection Compound 157
BPC-157 is the peptide people reach for when something will not heal. Tendons, ligaments, a gut that has been irritated by painkillers, an injury that has stalled. It is a short chain of amino acids copied from part of a protein your stomach already makes, and the animal research on it is unusually consistent for this category: across a lot of separate rat studies, injured tissue healed faster than it did without it. The gap is that this has largely not been repeated in people, and it is not an approved medicine, so nobody is checking what is in the vial you buy.
3
Gene variants
19+
Studies
AOD-9604
Body Composition StackEmerging EvidenceAdvanced Obesity Drug 9604 (hGH Fragment 177-191)
AOD-9604 is a fragment cut out of growth hormone, specifically the piece thought to handle fat burning, with the rest of the molecule left behind. The idea was elegant: get the fat-loss effect without the blood-sugar and growth effects of the whole hormone. It is also one of the very few peptides in this space that was put through a proper randomised human trial, which is the part vendors do not mention, because it did not beat the placebo. Development stopped there.
4
Gene variants
15+
Studies
Tesamorelin
Visceral Fat StackStrong EvidenceTesamorelin (GHRH Analog)
A stabilized growth-hormone-releasing-hormone (GHRH) analog and the only GH-axis peptide with an FDA approval (Egrifta, for visceral fat in HIV-associated lipodystrophy). It stimulates your own pulsatile GH release, which drives IGF-1 and preferential breakdown of visceral (deep belly) fat — backed by real randomized trial data on VAT reduction. Off-label use for visceral fat is common. WADA-banned in sport.
3
Gene variants
40+
Studies
Sourcing & access
Where to buy Retatrutide
Retatrutide is sold as a research compound, not a licensed medicine, so quality and legal status vary widely by country and vendor. If you're sourcing it, treat independent purity testing as non-negotiable.
- Insist on a recent third-party Certificate of Analysis (COA) for the exact batch — labs like Janoshik verify purity and identity.
- Check the legal status where you live before ordering — it differs from country to country.
- Reconstitute correctly with bacteriostatic water and start at a conservative dose.
Before you buy: see whether your DNA actually responds to Retatrutide, and at what dose. Analyze my DNA — $99 →
Educational information only, not medical advice. Some outbound links are affiliate links (disclosed, at no extra cost to you). Most peptides are not FDA-approved — consult a qualified professional and check your local laws before purchasing.
Worth knowing before you consider Retatrutide
Interactions and situations where there is a specific reason to be careful. Where the honest answer is that nobody has studied something, it says so and says what that leaves open.
- You cannot get the real thing
- It is still in Phase 3. Everything sold online under this name is a research vial of unknown content, not the compound Lilly is testing. Given how much attention this one gets, it is also among the most counterfeited.
- Heart rate goes up
- The glucagon component raises how much energy you burn, and your heart rate goes with it. In the trial it climbed, peaked around week 24, then came back down. Worth knowing if you already have a cardiac reason to care.
- The dose ramp is the whole game
- The impressive numbers came from people who spent months building up. Starting high produces nausea bad enough that most people quit before they get anywhere.
The evidence behind Retatrutide
Worth comparing against the research peptides. Retatrutide has fewer papers than BPC-157 does, 160 against 224, and seven of them are indexed as clinical trials where BPC-157 has none. A bigger pile of papers is not more evidence; what matters is whether any of it was a trial in people.
The literature, counted
Counted in PubMed on 2 August 2026 for retatrutide. Every figure links to the search that produced it, so you can re-run it. “Tagged human” is not the same as a human trial: that tag also covers work on human cells and reviews discussing people, which is why the trial count is given separately.
Studied in people
2 of 2The only kind that directly answers whether it works in humans.New England Journal of Medicine · 2023
HumanTriple-Hormone-Receptor Agonist Retatrutide for Obesity, a Phase 2 Trial
Jastreboff AM, Kaplan LM, Frías JP, et al.
Every dose figure on this page comes from here. Seven randomised groups, and least-squares mean weight change at 48 weeks running from −2.1% on placebo to −24.2% at 12 mg.
Triple-Hormone-Receptor Agonist Retatrutide for Obesity, a Phase 2 Trial — source for Retatrutide (opens in a new tab)Phase 2 · n=338 · 48 weeks
Read the paperClinicalTrials.gov
HumanTRIUMPH programme: Phase 3 trials of retatrutide in obesity
Registered and running. Results are not published yet, which is why the long-term picture is still open.
TRIUMPH programme: Phase 3 trials of retatrutide in obesity — source for Retatrutide (opens in a new tab)Phase 3
Read the paper
Last updated · literature counts verified against PubMed on
Frequently Asked Questions
Can I get retatrutide?
Not legitimately, no. It has not been approved by any regulator, which means no pharmacy can fill a prescription for it. The 24.2% figure that gets quoted everywhere comes from a mid-stage trial published in 2023. The larger trials that decide whether it gets approved are still running.
Why does it work better than Mounjaro or Ozempic?
It adds a third hormone the others do not use, and that one raises the energy you burn at rest rather than just curbing appetite. So weight comes off two ways instead of one. Worth being careful with head-to-head comparisons, though: retatrutide's 24.2% comes from a 48-week mid-stage trial of 338 people, while Mounjaro's 22.5% comes from a 72-week late-stage trial of 2,539. Different trials, different lengths, different sizes.
How much weight would I actually lose?
Nobody can tell you that, and anyone who does is guessing. What the trial gives you is group averages: 8.7% on the lowest dose, 24.2% on the highest. Individuals within those groups varied a lot. Some of that variation is genetic, which is what our report looks at, but the honest answer is that genetics explains part of it and not all of it.
What do my genes have to do with it?
Retatrutide works through three receptors, and the genes that build those receptors vary from person to person. The interesting one here is GCGR, because it handles the energy-burning signal that only retatrutide uses. It is beside the point for Ozempic or Mounjaro. This is about the receptors, not about how fast your liver clears the drug.
Learn more about Retatrutide
peptide guides
In depthWhy Retatrutide Outperforms Ozempic and Mounjaro in Weight Loss (And Why It Isn't Approved Yet)
13 min read
genetics
Semaglutide vs Tirzepatide: Which Actually Works Better Based on Your GLP-1 Receptor Gene?
11 min read
comparisons
In depthTirzepatide vs Retatrutide vs Semaglutide: Which GLP Agonist Wins by Genotype?
11 min read
Your next move
Two ways forward with Retatrutide.
Not sure it's for you?
How does Retatrutide relate to your genes?
Your report scores Retatrutide against your receptor, pharmacogene and pathway variants and shows the genetic markers relevant to it, with commonly cited dosing information to review with a clinician.
Analyze my DNA — $99