Retatrutide
LY3437943; "triple G"; "Reta"; "the Godzilla peptide" (community); GGG tri-agonist
Checked Oct 28, 2026
The short answer
Proven in humans for weight loss in adults with obesity
Grade A for weight loss in adults with obesity: several randomized trials, including two Phase 3 trials published in September 2026, beat placebo by wide margins.
- Approved?
- Not approved for any use.
- Safety: C, thinly characterized
- Stomach side effects are common and dose-related, a new skin-sensation side effect (dysesthesia) appeared in Phase 3, and no approved product exists, so vials outside trials are of unknown identity and purity.
We tried it. This is what happened.
- Retatrutide: the low dose, on purpose RunningMost people run this for big weight loss. I run a fraction of the trial doses for glucose handling, and I adjust it week to week.
The full answer: what it is for, the dose, the units
What people take it for: People take it for weight loss. It is also studied in type 2 diabetes and fatty liver disease. It is an unapproved Eli Lilly drug (LY3437943) that hits three hormone receptors: GLP-1, GIP and glucagon.
Does it work for weight loss in adults with obesity? A, proven in humans. Result: worked.
Grade A for weight loss in adults with obesity: several randomized trials, including two Phase 3 trials published in September 2026, beat placebo by wide margins. In TRIUMPH-1, 12 mg weekly gave 25.0% weight loss against 3.9% on placebo at 80 weeks.
No approval for any use.
Safety: C, thinly characterized. Stomach side effects are common and dose-related, a new skin-sensation side effect (dysesthesia) appeared in Phase 3, and no approved product exists, so vials outside trials are of unknown identity and purity.
Do not use if: Contraindicated (class labeling for GLP-1 agonists) in personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN2).
Could it be placebo? Trials for this use beat placebo on body weight by large margins (TRIUMPH-1, 12 mg: 25.0% versus 3.9% at 80 weeks), and weight is measured on a scale, so placebo does not explain the effect; the appetite-quieting reports from users have no controlled data of their own.
The dose people use, and the units to draw
Published trials gave it by weekly injection under the skin at 4 mg, 9 mg or 12 mg in Phase 3, and 1 mg to 12 mg in Phase 2. No label exists, so there is no approved dose, and no verified dose statement from Huberman, Dr. Abud Bakri, Examine or Attia was found.
| Source | Dose | How often and how | Who it was for | Link |
|---|---|---|---|---|
| Jastreboff et al., Phase 2 obesity trial (NEJM 2023) | Maintenance 1 mg, 4 mg, 8 mg or 12 mg; starting dose 2 mg or 4 mg in the 4, 8 and 12 mg arms | Once weekly, subcutaneous, 48 weeks; 2 mg start gave fewer stomach side effects than 4 mg start | 338 adults with obesity or overweight plus a weight-related condition | Abstract, randomization arms and dose table |
| Jastreboff et al., TRIUMPH-1 (NEJM 2026) | 4 mg, 9 mg or 12 mg | Once weekly, subcutaneous, 80 weeks | 2,339 adults with obesity without diabetes | Abstract, methods and results |
| Bajaj et al., TRANSCEND-T2D-1 (Lancet 2026) | 4 mg, 9 mg or 12 mg | Once weekly, subcutaneous, 40 weeks | 537 adults with type 2 diabetes managed by diet and exercise alone | Abstract, methods and results |
| Bellido et al., TRIUMPH-2 (Lancet 2026) | 4 mg, 9 mg or 12 mg | Once weekly, self-administered subcutaneous, 80 weeks | 1,152 adults with obesity and type 2 diabetes | Abstract, methods and results |
| Rosenstock et al., Phase 2 type 2 diabetes trial (Lancet 2023) | 0.5 mg, 4 mg, 8 mg or 12 mg; 2 mg starting dose in the 4, 8 and 12 mg escalation arms | Once weekly, subcutaneous, 24 weeks for the main endpoint and 36 weeks for weight | 281 adults with type 2 diabetes | Abstract, arms and results |
| Sanyal et al., Phase 2a MASLD substudy (Nature Medicine 2024) | 1 mg, 4 mg, 8 mg or 12 mg | Once weekly, subcutaneous, 48 weeks; doses escalated every 4 weeks where applicable | 98 adults with fatty liver disease and at least 10% liver fat | Abstract, methods |
| Dr. Abud Bakri on Huberman Lab, Peptides: The Science, Uses & Safety (June 1, 2026) | No verified dose statement found | Discussed as a drug class and a gray-market risk; no recommended dose given | General audience | Chapter list: Retatrutide; Drug Patents & Nomenclature at 02:33:53. The transcript text is not time-stamped; the only milligram figure near the drug is an aside about young patients, not a dose recommendation |
Phase 3 trials tested 4 mg to 12 mg once weekly under the skin (TRIUMPH-1, TRANSCEND-T2D-1, TRIUMPH-2); Phase 2 trials went from 0.5 mg or 1 mg up to 12 mg.
No FDA, EMA or DailyMed label exists because the drug is unapproved. Examine and Attia pages on retatrutide dosing were searched and none was found. Earlier community starting doses and a step schedule on the site had no named source that could be opened, so they are removed.
Reported by the named source, never prescribed by us.
How many units do I draw?
Use the calculator: units on the syringe equal dose in mg divided by (vial mg divided by water mL), times 100 for a U-100 syringe. Open the dose calculator
Why it might work
- Subcutaneous injection → triple-receptor engagementRetatrutide binds GLP-1R
- GCGR activation → hepatic energy expenditure increaseGlucagon receptor agonism is assumed t
- GLP-1R + GIPR co-activation → appetite suppression and insulin sensitizationThe incretin components suppress appet
- Combined energy-flux shift → accelerated fat mobilizationThe triple combination is hypothesized
- Potential cardiovascular and NASH remodelingGCGR agonism is associated with reduce
Assumed pathway, not shown in people.
Synthetic single-peptide triple agonist at the GLP-1, GIP, and glucagon receptors. GLP-1 + GIP drive appetite suppression, satiety, and improved insulin response; the added glucagon-receptor agonism is thought to increase energy expenditure and hepatic fat oxidation, contributing to the larger weight loss and strong liver-fat reduction versus dual agonists. Mechanism is well-characterized from extensive Lilly preclinical and clinical pharmacology (not "assumed"), though it remains investigational rather than approved-label.
The trials, claim by claim
All trials listed for obesity and type 2 diabetes worked on weight and blood sugar; the fatty-liver result is a single Phase 2a substudy.
Phase 2 obesity RCT (n=338, 48 wks): mean weight loss -24.2% at 12 mg vs -2.1% placebo; 83% of 12 mg group lost ≥15% body weight.
Result: worked
Double-blind, randomized, placebo-controlled Phase 2 trial published in NEJM (Jastreboff et al., 2023).
PubMed: Retatrutide Phase 2 obesity trial (NEJM 2023)Phase 3 TRIUMPH-1 (obesity without diabetes, n=2,339, 80 wks): all doses met primary/key secondary endpoints; 12 mg produced mean weight loss of 25.0% vs 3.9% on placebo (treatment-regimen estimand; 28.3% if everyone stayed on drug); 65.3% on 12 mg reached BMI <30.
Result: worked
Double-blind placebo-controlled Phase 3 RCT, topline May 2026, published in NEJM on September 29, 2026 (Jastreboff et al.).
PubMed: TRIUMPH-1 (Jastreboff, NEJM 2026)Phase 3 in type 2 diabetes (TRANSCEND-T2D-1, 40 wks): met primary and all key secondary endpoints; A1C reduction ~1.7-2.0% across doses; mean weight loss at 12 mg of 15.3% versus 2.6% on placebo (treatment-regimen estimand, everyone counted); 16.8% under the efficacy estimand (adherent participants only).
Result: worked
Phase 3 RCT in T2D (n=537), topline March 2026, published in The Lancet on June 6, 2026 (Bajaj et al.).
PubMed: TRANSCEND-T2D-1 (Bajaj, The Lancet 2026); registry NCT06354660Liver fat: Phase 2a MASLD trial showed large reductions in liver fat content (high proportions reaching normal liver-fat thresholds) at 24-48 weeks.
Result: worked
Randomized Phase 2a sub-study published in Nature Medicine (2024).
PubMed: Retatrutide for MASLD, phase 2a (Sanyal, Nature Medicine 2024)NOT FDA-approved as of October 28, 2026, entirely investigational; no approved finished product exists. Lilly says it will submit a Biologics License Application in the first quarter of 2027.
FDA's page on unapproved GLP-1 drugs (current as of Oct 1, 2026) states that retatrutide cannot be used in compounding under federal law. Phase 3 readouts for TRIUMPH-1 to -4 are complete and the filing is still ahead. This regulatory fact is itself grade-A certain.
FDA: Concerns with unapproved GLP-1 drugs (current as of 2026-10-01)In TRIUMPH-2 (n=1,152, adults with type 2 diabetes and obesity) retatrutide 12 mg lowered weight 18.8% versus 5.1% on placebo (treatment-regimen) and A1C by about 1.5 points.
Result: worked
Phase 3 RCT published in The Lancet, 2026-09-29.
PubMed: TRIUMPH-2 (Bellido, The Lancet 2026)Dysesthesia (abnormal skin sensation) was more frequent on retatrutide than placebo in every Phase 3 trial reported: 5.1 to 12.5% across doses in TRIUMPH-1 against 0.9% on placebo, and 20.9% at 12 mg in TRIUMPH-4 against 0.7%. Lilly describes it as mostly mild to moderate.
Result: worked
Adverse event tables for several Phase 3 RCTs: the TRIUMPH-2 paper in The Lancet reports dysesthesia at 4 to 7% against 1%, and the TRIUMPH-1 and TRIUMPH-4 figures come from Lilly releases.
Lilly: TRIUMPH-1 and TRANSCEND-T2D-1 results at ADA 2026 (June 6, 2026)Risks and the label warnings
Adverse events
Most common are dose-related gastrointestinal events (nausea about 42 to 43% at 12 mg in TRIUMPH-1 and TRIUMPH-4, vomiting, diarrhea, constipation), mostly mild-to-moderate. Dysesthesia (abnormal skin sensation) is dose-related: 5 to 21% at 9 to 12 mg vs under 1.5% on placebo. Adverse-event discontinuation reached 11 to 18% at 12 mg. Hypotension symptoms are also reported, more often with blood-pressure medicines. Resting heart rate rises with dose, peaking around week 24 in Phase 2 and then declining (the Phase 3 reports we read give no heart-rate figures). Decreased appetite, fatigue.
Contraindications
Contraindicated (class labeling for GLP-1 agonists) in personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN2). Caution/avoid with history of pancreatitis, severe GI disease/gastroparesis, active gallbladder disease. Not for pregnancy/breastfeeding. Because no approved product exists, there is no prescriber-vetted contraindication screen for gray-market users.
Theoretical concerns
Glucagon-receptor agonism can transiently raise fasting glucose and is theoretically counterproductive in poorly controlled diabetes (net effect in trials was glucose-lowering, as GLP-1 dominates). Class-effect rodent thyroid C-cell tumors underlie the boxed-warning concern (human relevance debated). Potential for increased heart rate to matter in susceptible cardiac patients pending CV-outcome data. In TRIUMPH-3 the cardiovascular event counts were small (MACE-3: 27 vs 23 events, hazard ratio 1.12, wide confidence interval) and the trial was not designed to prove benefit or harm.
What nobody knows yet
No FDA-approved product means no quality-controlled finished drug, gray-market vials carry unknown identity, purity, dose accuracy, and sterility risk. Long-term (>80 wk) safety, cardiovascular-outcome data (a dedicated outcomes trial has an estimated primary completion in 2029), and post-marketing surveillance do not yet exist. Effects of rapid 25-28% weight loss on lean mass, bone, and very-low-BMI individuals self-dosing outside trial supervision are unquantified.
What else could explain the result
Trial results come with diet/lifestyle counseling and dose titration, community results conflate the drug with concurrent calorie restriction. Affiliate/vendor blogs (peptide sellers, telehealth, "research chemical" sites) dominate search results and inflate enthusiasm while underselling that the drug is unapproved. Forum weight-loss numbers cannot verify actual compound identity or dose. Distinguish the legitimate Lilly trial evidence (real) from the gray-market product (uncharacterized).
Is the vial what it says?
Confirm any vial via independent third-party mass-spec/HPLC purity and identity testing before assuming contents; verify reconstitution math against actual labeled mg. Cross-check claims only against primary trial sources (NEJM, Lancet, Nature Medicine, ClinicalTrials.gov, Lilly investor releases), not vendor blogs. Note that no DailyMed/FDA label exists, so there is no official prescribing information to verify dosing against.
Half-life and storage
Half-life: Approximately 6 days, supporting once-weekly dosing; dose-proportional pharmacokinetics across the 0.5-12 mg range with no clinically meaningful accumulation beyond expected steady state.
Once mixed: As a peptide drug, retatrutide is reconstituted from lyophilized powder with bacteriostatic or sterile water and is sensitive to vigorous agitation, heat, and light; reconstituted solution should be refrigerated. The larger risk is not handling but provenance, unverified gray-market lyophilate may be underdosed, mislabeled, or contaminated, making reconstitution math meaningless without identity/purity testing.
What I noticed, and what people report
Case study
- Retatrutide: the low dose, on purpose RunningMost people run this for big weight loss. I run a fraction of the trial doses for glucose handling, and I adjust it week to week.
What people report
Volume of reports: strong. Large, consistent community + practitioner record.
High. A large, active community (r/Retatrutide ~30K+ members) plus extensive coverage across telehealth, medspa, and peptide-vendor sites. It is one of the most-discussed investigational metabolic compounds online, frequently dubbed the "Godzilla" of weight-loss drugs.
High and consistent on the core experience, large weight loss and strong appetite/"food-noise" suppression are near-universal in reports, as are dose-related GI side effects (nausea/fatigue appear in 70%+ of weekly experience threads). Consistency tracks the trial data closely, which raises credibility that real material is circulating, but does not verify any individual vial.
Mixed-to-discounted. The underlying clinical evidence is genuinely top-tier, but most search-surface content is affiliate/commercial (peptide sellers, telehealth funnels, "research-only" vendors) with a strong incentive to overstate safety and downplay that the drug is unapproved. Discount vendor blogs heavily; weight anecdotes carry weight only because they align with independent RCTs, not on their own.
- Overwhelmingly the most-reported benefit is dramatic appetite and 'food-noise' suppression, many users say the psychological relief from constant food thoughts rivals or exceeds the weight loss itself.
- Users frequently report continued weight loss without the plateau they experienced on semaglutide or tirzepatide, and many describe switching to retatrutide specifically to break a stall.
- GI side effects dominate negative reports, nausea, fatigue, and constipation are common, especially during dose escalation.
- A recurring sober thread is awareness that the drug is unapproved and sourced gray-market, with experienced users urging third-party purity testing and cautioning newcomers that vial contents and dosing are unverifiable.
Reports are anecdote, not proof.
Can you tell if it is working?
DEXA is the direct efficacy readout (total fat mass and android/visceral fat fall hard), with weight/waist as the equally-direct, most-validated corroboration; CGM only helps if you start dysglycemic.
Bloodwork
A lab moves, but it's noisy, indirect, or off-target, treat it as a hint, not proof.
Retatrutide is a single-peptide triple agonist at the GLP-1, GIP, and glucagon receptors. It augments glucose-dependent insulin secretion, drives large weight loss, and via glucagon-receptor agonism increases hepatic fat oxidation. Those actions do shift standard glycemic, lipid, and liver markers, so it is not blood-silent. But its headline effect (weight loss) is measured on a scale, and the blood markers move meaningfully only when baseline glycemia/liver fat are abnormal, so routine bloodwork is an indirect, population-dependent proxy for efficacy rather than a clean readout.
Falls in people with elevated baseline glycemia. In the phase 2 T2D trial the highest dose lowered HbA1c ~2 percentage points vs baseline at 24 weeks; magnitude scales with how elevated baseline is, and a metabolically healthy user near normal may barely move.
GLP-1/GIP components enhance glucose-dependent insulin secretion and, with weight loss, improve 3-month average glycemia (Rosenstock 2023).
Drops toward the normal fasting range (70-99 mg/dL) in dysglycemic users; may be near-flat if baseline is already normal. Faster-moving read than HbA1c.
Incretin action plus improved insulin sensitivity from weight loss lowers fasting glucose; glucagon component nudges the other way but nets to lowering in trials.
Fall, often substantially when baseline triglycerides are elevated; total/LDL shifts are smaller and unreliable. Confounded by weight loss, so supportive not proof.
Improved insulin sensitivity and reduced hepatic/visceral fat lower circulating triglycerides.
Elevated liver enzymes trend toward normal, mirroring large hepatic-fat reductions (phase 2a MASLD trial: normal liver fat <5% reached by up to 86% at 12 mg). Confounded by weight loss itself, so treat as supportive.
Glucagon-receptor agonism drives hepatic fat oxidation; falling aminotransferases track the liver-fat reductions (Sanyal 2024).
Declines with improved HOMA-IR, signaling better insulin sensitivity. Noisy and best interpreted only alongside a paired fasting glucose; weakest of the set.
Weight loss and incretin-driven metabolic improvement reduce the insulin needed to control glucose.
Draw baseline
before first dose (draw the full panel before starting, ideally before dose escalation begins)
Retest
8-12 weeks (HbA1c needs at least 8-12 weeks to move given the ~3-month RBC lifespan; fasting glucose, insulin, and triglycerides shift within 2-4 weeks but are best retested together at the 12-week mark)
Read this before you spend on labs
Bloodwork only partially verifies retatrutide. The glycemic markers (HbA1c, fasting glucose) genuinely track its metabolic action and are well documented in humans, but the effect is strongest in people with elevated baseline glycemia (prediabetes/T2D). In a metabolically healthy person taking it purely for weight loss, baseline HbA1c and glucose may already be normal and barely move, so a flat panel does NOT mean the drug isn't working. The headline effect (weight loss) is measured on a scale, not in blood. Liver enzymes and triglycerides shift too but are confounded by the weight loss itself, so read them as supporting evidence rather than standalone proof.
- Rosenstock J et al. Retatrutide, a GIP/GLP-1/glucagon receptor agonist, for people with type 2 diabetes: phase 2 trial. Lancet 2023 (HbA1c ~2% reduction at highest dose).
- Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial. NEJM 2023 (~24% weight loss at 12 mg).
- Sanyal AJ et al. Retatrutide for metabolic dysfunction-associated steatotic liver disease: randomized phase 2a trial. Nat Med 2024 (dose-dependent liver-fat reduction).
Other ways to track it
DEXA scan, total body fat mass, android (visceral) fat, and lean mass
A working result shows total fat mass and android/visceral fat dropping clearly. In the phase 2 T2D DEXA body-composition substudy (Lancet Diabetes & Endocrinology, 2025; n=189) top-dose changes were large: total fat mass down up to ~-26% (up to ~-10.9 kg) and android visceral fat down up to ~-31%. CRITICAL honest caveat: lean mass also falls meaningfully, up to ~6.5 kg, and in the pooled 4/8/12 mg analysis lean tissue made up roughly 35% of total weight lost (fat loss index ~65%), NOT the smaller fraction sometimes quoted. So 'working' means fat/visceral fat falling much faster than lean, not lean collapsing alongside it. DEXA is the only accessible tool that separates the two, so track the fat-to-lean split rather than scale weight alone. Note DEXA's visceral estimate is regional (android) and less precise than MRI/CT, the large percent VAT drop rides on a small absolute change, so read it as a trend, not a hard number.
The triple agonist pairs GLP-1/GIP appetite suppression with glucagon-driven energy expenditure and fat oxidation. A dedicated retatrutide DEXA substudy in humans confirmed significant, dose-dependent total-fat and android/visceral-fat reduction, measured efficacy, not mechanism hope.
Tape-measure waist circumference + scale weight (weekly); home BP cuff (baseline + monthly)
Weight and waist are the most accessible direct efficacy readouts and were the primary trial endpoints. If it's working both fall substantially and steadily (phase 2 obesity trial showed up to ~24% body-weight loss at 12 mg/48 weeks, with waist reductions on the order of several to ~20 cm at higher doses). Blood pressure tends to drift modestly downward with the weight loss. Honest counter-signal to not misread: resting heart rate can tick UP a few bpm on this drug class (a prespecified finding in the trials), that's expected pharmacology, not failure, so don't treat a higher resting HR as a red flag on its own, and don't count it as an efficacy signal either.
Body weight and waist circumference are the most validated, best-powered efficacy endpoints for this class, and retatrutide produced the largest reductions of any incretin agent in its trials. Waist specifically tracks the visceral-fat loss that DEXA confirms.
14-day continuous glucose monitor, mean glucose, time-in-range, glucose variability (post-meal excursions)
Conditional. If your baseline glucose is elevated, a working result shows mean glucose falling, time-in-range climbing, and post-meal spikes flattening, trial HbA1c drops of ~1.7-2.0 points in T2D translate to a clearly lower, tighter CGM trace. But this is downgraded to PARTIAL because it only reflects efficacy when there's dysglycemia to correct: if you start normoglycemic, expect little to no CGM movement, and glucose is a secondary axis for a weight-loss compound, not its primary indication. The glucagon-receptor arm also mildly opposes glucose lowering (net effect across trials is still downward). Read CGM as a bonus readout for the dysglycemic subset, not a general efficacy tracker.
GLP-1 + GIP agonism enhances glucose-dependent insulin secretion and cuts intake, and retatrutide's documented T2D HbA1c reductions are among the strongest in the class, but that signal only appears on CGM when baseline glucose is high enough to move.
Bottom line
Retatrutide is genuinely, objectively trackable, DEXA is the anchor (direct fat-mass and android/visceral-fat readout, from a real human substudy), and weight/waist are equally direct and the actual trial primary endpoints; CGM is only a partial, conditional readout that lights up if baseline glucose is already elevated. Blood (HbA1c, glucose, triglycerides, ALT/AST) covers the metabolic/liver-fat side. Hard honest caveats: (1) meaningful lean mass is lost, roughly 35% of total weight lost was lean tissue in the DEXA substudy, so track body composition on DEXA (not the scale) and pair with resistance training plus adequate protein; (2) resting HR tends to RISE a few bpm, expected pharmacology, not an efficacy signal; (3) sleep/wearable, VO2max, urine, stool, and genetic testing add nothing validated for this compound. Finally, every number here is from investigational trials on pharmaceutical-grade drug (not FDA-approved as of October 2026); gray-market material has unverified identity and purity, so your own tracking is the only real evidence it's doing anything.
Logging baseline vs retest is the whole game. The Truth Tracker is our free log for bloodwork, DEXA, genetics, and wearable data, bring your own numbers.
How to track itHistory
First documented human use: First-in-human Phase 1 single/multiple-ascending-dose studies in healthy adults and adults with type 2 diabetes began ~2019-2020 (Eli Lilly, LY3437943); first peer-reviewed human data published in The Lancet in 2022 (Phase 1b/2 multiple-ascending-dose, T2D). Pivotal Phase 2 obesity trial published NEJM, online June 26, 2023.
- ~2019-2020First-in-human Phase 1 single/multiple-ascending-dose studies begin (Eli Lilly, LY3437943) in healthy adults and adults with T2D.
- 2022First peer-reviewed human data published in The Lancet (Phase 1b/2 multiple-ascending-dose in type 2 diabetes); ~6-day half-life supports once-weekly dosing.
- Jun 26, 2023Pivotal Phase 2 obesity RCT published in NEJM, up to 24.2% mean weight loss at 48 weeks; triggers intense media and community attention.
- 2024Phase 2a MASLD (liver) results published in Nature Medicine showing large liver-fat reductions.
- Dec 2025TRIUMPH-4 (obesity + knee osteoarthritis) topline: ~28.7% mean weight loss at 68 wks (12 mg, efficacy estimand) plus substantial WOMAC pain relief.
- Mar 19, 2026TRANSCEND-T2D-1 (type 2 diabetes, n=537) topline: A1C down 1.7 to 2.0 points across doses.
- May 21, 2026TRIUMPH-1 pivotal Phase 3 obesity topline announced: bariatric-level weight loss, all doses met endpoints.
- Jun 6, 2026TRIUMPH-1 detailed results presented at ADA; TRANSCEND-T2D-1 published in The Lancet.
- July 23, 2026Lilly reports topline TRIUMPH-2 (T2D) and TRIUMPH-3 (established CV disease) Phase 3 results, up to 22.6% average weight loss at 80 weeks in TRIUMPH-3, and says it will submit to FDA in the first quarter of 2027. Still no regulatory approval.
- Sep 29, 2026TRIUMPH-1 published in NEJM (n=2,339) and TRIUMPH-2 published in The Lancet (n=1,152); a dysesthesia signal is reported across the Phase 3 trials.
- Oct 1, 2026FDA's page on unapproved GLP-1 drugs states retatrutide cannot be used in compounding under federal law. Not approved anywhere.
All sources
- NEJM Phase 2 obesity trial (PubMed)(Pivotal double-blind RCT, n=338, 48 wks; up to -24.2% weight at 12 mg. Primary grade-B evidence.)
- Retatrutide T2D phase 2 trial (Rosenstock, Lancet 2023, PubMed)(Phase 2 RCT in type 2 diabetes (Lancet) establishing glycemic + weight effects.)
- Retatrutide MASLD phase 2a (Sanyal, Nature Medicine 2024, PubMed)(Nature Medicine 2024 liver-fat sub-study; large reductions in hepatic fat.)
- PubMed. TRIUMPH-1 obesity Phase 3 (Jastreboff, NEJM 2026)(Pivotal Phase 3, n=2,339; 25.0% (treatment-regimen) to 28.3% (efficacy) at 12 mg over 80 wks. Published Sept 29, 2026.)
- ClinicalTrials.gov. TRIUMPH-1 obesity Phase 3 (NCT05929066)(Registry record for the pivotal Phase 3.)
- PubMed. TRIUMPH-2 obesity with type 2 diabetes (Bellido, The Lancet 2026)(Phase 3, n=1,152; published Sept 29, 2026.)
- ClinicalTrials.gov. TRIUMPH-2 obesity with type 2 diabetes (NCT05929079)(Registry record for TRIUMPH-2 (this number was previously listed under TRANSCEND-T2D-1).)
- PubMed. TRANSCEND-T2D-1 type 2 diabetes Phase 3 (Bajaj, The Lancet 2026)(Phase 3, n=537, 40 wks; published June 6, 2026. Registry: NCT06354660.)
- ClinicalTrials.gov. TRANSCEND-T2D-1 (NCT06354660)(Registry record for the type 2 diabetes Phase 3.)
- ClinicalTrials.gov. Retatrutide + cardiovascular disease, TRIUMPH-3 (NCT05882045)(Phase 3 in obesity + established CV disease; topline July 2026, no full paper found yet; a dedicated CV-outcome trial is still ahead.)
- PubMed. LY3437943 phase 1b in type 2 diabetes (Urva, Lancet 2022)(Source for the half-life of about 6 days and once-weekly dosing.)
- FDA: Concerns with unapproved GLP-1 drugs (current as of 2026-10-01)(States retatrutide cannot be used in compounding under federal law, and that no approved finished product exists, the central safety caveat.)
- ClinicalTrials.gov. Retatrutide expanded access (NCT07629401)(Single-patient expanded access, limited to adults with BMI 35 or higher, serious obesity-related complications, and no response to approved therapy.)
- Eli Lilly (PR Newswire). TRIUMPH-2 and TRIUMPH-3 results, July 23, 2026(Company release: TRIUMPH-2 and -3 results and the plan to submit a Biologics License Application in Q1 2027.)
- Eli Lilly investor release. TRIUMPH-1 topline(Company topline for pivotal Phase 3; full paper in NEJM, September 29, 2026.)
- Jastreboff AM et al. Triple-Hormone-Receptor Agonist Retatrutide for Obesity, A Phase 2 Trial. N Engl J Med 2023;389:514-526. PMID 37366315. DOI 10.1056/NEJMoa2301972(dose table)
- Jastreboff AM et al. Retatrutide, a Triple Hormone Receptor Agonist, for Treatment of Obesity. N Engl J Med 2026 (online Sep 29). PMID 42814954. DOI 10.1056/NEJMoa2604169(dose table)
- Bajaj HS et al. Lancet 2026;407(10546):2402-2413. PMID 42250575. DOI 10.1016/S0140-6736(26)00967-0(dose table)
- Bellido V et al. Retatrutide in adults with obesity and type 2 diabetes (TRIUMPH-2). Lancet 2026;408(10563):1455-1472. PMID 42810372. DOI 10.1016/S0140-6736(26)01861-1(dose table)
- Rosenstock J et al. Lancet 2023;402(10401):529-544. PMID 37385280. DOI 10.1016/S0140-6736(23)01053-X(dose table)
- Sanyal AJ et al. Nat Med 2024;30(7):2037-2048. DOI 10.1038/s41591-024-03018-2. PMID 38858523(dose table)
- Huberman Lab, episode with Dr. Abud Bakri, June 1, 2026(dose table)
Not medical advice. Grades reflect the evidence as of the date above and will change as data arrives. Reports from users are anecdote, not proof. Talk to a licensed clinician before you act on anything here.