Retatrutide

Areas of active research — not promised effects

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Retatrutide has not been approved by the FDA and no New Drug Application has been submitted as of May 2026. Access is legally limited to enrolled participants in Eli Lilly's TRIUMPH Phase 3 clinical trial program. No prescription pathway or compounding exemption exists; unlike semaglutide or tirzepatide, there is no approved reference drug to trigger a compounding shortage exemption. The fda19 flag is not applicable (fda19: false). NDA submission is anticipated Q4 2026; FDA approval, if granted, is projected no earlier than late 2027.

Transparent blend · bci-1.0 · never paid-placement

Primary name

Retatrutide

Origin

Fully synthetic 39-amino acid peptide developed by Eli Lilly (code: LY3437943). Conjugated to a C20 fatty diacid moiety enabling albumin binding and extended half-life. Not derived from any endogenous sequence; engineered de novo for balanced multi-receptor agonism.

Registry IDs

PubChem CID

171934787

CAS

2381089-83-2

InChIKey

MLOLQJNKXBNWFW-JMUPIODPSA-N

InChIKey

MLOLQJNKXBNWFW-JMUPIODPSA-N

Appearance

White to off-white lyophilized powder (vendor-reported; no USP monograph available)

Solubility

Soluble in aqueous buffers; the fatty diacid moiety confers amphiphilic characte…

Sequence not available in current seed.

Stability: Stabilized in vivo by albumin binding via the C20 fatty diacid moiety; in vitro stability data for RUO material not found in published literature. Acylated pept

Vial sizes

null mg

Purity grades

research grade

Salt forms

Free base (primary)

• GHS hazard class on file
• PPE & spill response
• Disposal guidance
• Not-for-human-consumption posture

How much research exists, and of what maturity — never a verdict on whether it works.

Mechanism of action

• Retatrutide simultaneously activates three receptors: the glucagon-like peptide-1 receptor (GLP-1R), the glucose-dependent insulinotropic polypeptide receptor (GIPR), and the glucagon receptor (GCGR)
• GLP-1R and GIPR engagement promotes glucose-stimulated insulin secretion and appetite suppression via central satiety pathways, while GCGR activation increases energy expenditure through enhanced hepatic glucose output and thermogenesis
• Relative to the endogenous hormones, retatrutide is approximately 8.9-fold more potent at GIPR, and about 0.3–0.4-fold the potency at GCGR and GLP-1R respectively, producing a balanced anorectic plus energy-expenditure profile
• In the Phase 2 obesity trial, mean body-weight reduction at 48 weeks reached 24.2% in the highest-dose (12 mg) group, with the glucagon component contributing additive fat-mass loss beyond what incretin agonism alone achieves

Pharmacokinetics (ADME)

Half-life

~6 days (enables once-weekly subcutaneous dosing; steady state reached at ~4–5 weeks)

Clearance

Renal and proteolytic; the fatty diacid–albumin interaction substantially retards clearance; approximately 97% eliminated within 30 days of last dose

PK–PD note: PK is dose-proportional in clinical studies. The fatty diacid moiety provides albumin binding that protects against DPP-4 enzymatic degradation and extends systemic exposure. Data sourced from Phase 1…

Reading the evidence

• Evidence quality and gaps vary by application — see the cited grades above.
• Indexed-article counts span all evidence tiers, not only completed human trials.
• No first-party human-dosing, efficacy, or benefit claims are made here.

Key reviews & evidence-gap sources

• Abouelmagd et al. Efficacy and safety of retatrutide...systematic review and meta-analysis. Proc (Bayl Univ Med Cent). 2025;38(3):291-303. PMID 40291085 — Systematic review/meta-analysis; 3 RCTs, 878 patients
• Pasqualotto et al. Effects of once-weekly subcutaneous retatrutide on weight and metabolic markers: systematic review and meta-analysis. Metabol Open. 2024;24:100321. PMID 39318607 — Systematic review/meta-analysis; 3 RCTs, 640 patients
• Efficacy and safety of triple hormone receptor agonist retatrutide for the management of obesity: systematic review and meta-analysis. PMID 39817343 — Systematic review/meta-analysis
• Katsi et al. Retatrutide—A Game Changer in Obesity Pharmacotherapy. Biomolecules. 2025;15(6):796. PMID 40563436 — Narrative review
• Effect of Retatrutide on Blood Pressure and Lipid Levels: Systematic Review and Meta-analysis. PMID 42371360 — Systematic review/meta-analysis

5 registered trials — 0 currently recruiting.

Phase 3
NCT05882045
A Study of Retatrutide (LY3437943) in Participants With Obesity and Cardiovascular Disease

ACTIVE_NOT_RECRUITING

Phase 3
NCT06662383
A Study of Retatrutide (LY3437943) Compared to Tirzepatide (LY3298176) in Adults Who Have Obesity

ACTIVE_NOT_RECRUITING

Phase 1
NCT06039826
A Study of LY3437943 in Postmenopausal Female Participants Who Are Overweight or Obese

COMPLETED

Phase 3
NCT06354660
Effect of Retatrutide Compared With Placebo in Adult Participants With Type 2 Diabetes and Inadequate Glycemic Control With Diet and Exercise Alone (TRANSCEND-T2D-1)

COMPLETED

Phase 3
NCT05931367
A Study of Retatrutide (LY3437943) Once Weekly in Participants Who Have Obesity or Overweight and Osteoarthritis of the Knee

COMPLETED

Summary (literature)

Based on Phase 2 data (Jastreboff et al., NEJM 2023) and emerging Phase 3 signals: the most frequent adverse events are gastrointestinal—nausea (up to ~60% at 12 mg), diarrhea (~33%), vomiting (~21%), and constipation—occurring predominantly during dose escalation, generally mild…

WADA status

Not listed by name on WADA Prohibited List (2026). However, as an unapproved pharmacological agent with GLP-1R and GIPR/GCGR agonism, it falls under WADA S0 (No…

Dominant research route: Subcutaneous injection (SC), once weekly

Phase 1 (SAD/MAD in healthy volunteers and T2DM), Phase 2 obesity trial (NCT04881760), Phase 3 TRIUMPH program — humans

Bioavailability: Pharmacokinetics described as dose-proportional with a half-life of approximately 6 days, enabling once-weekly administration; Tmax reported 12–72 h after subcutaneous dosing in Phase 1. Precise absolute SC bioavailability value not published in retrieved sources.

Dominant research route. Phase 2 trial randomized adults to subcutaneous retatrutide (1, 4, 8, or 12 mg) or placebo once weekly for 48 weeks. Phase 1b in T2DM used once-weekly SC injections across 5 ascending dose groups over 12 weeks.

No retatrutide-specific human or animal intranasal studies retrieved; only mechanistic/general peptide-delivery discussion

Bioavailability: Retatrutide molecular weight ~4,895 Da places it in the 1,000–6,000 Da range where nasal absorption is challenging but theoretically possible with enhancers; no retatrutide-specific bioavailability data. For reference, intranasal unmodified GLP-1 in a Diabetes Care trial showed ~2.7% bioavailability vs IV.

Intranasal retatrutide is an emerging/theoretical research area only; no clinical trials of intranasal retatrutide were identified. General nasal peptide delivery principles (mucociliary clearance ~15–20 min window, paracellular tight-junction ~1,000 Da cutoff) cited from aggregator discussion, not retatrutide-specific data.

No oral retatrutide formulation or human oral study retrieved

Bioavailability: No oral bioavailability data for retatrutide. As a ~34-amino-acid peptide (~4,895 Da) conjugated to a C18 fatty diacid moiety, oral absorption would be expected to be negligible without absorption enhancers; no oral formulation is in clinical development per retrieved sources.

Oral route not studied for retatrutide. Oral stability note (distinct from absorption): peptide backbone susceptible to proteolytic degradation in the GI tract; fatty-acid conjugation extends half-life via albumin binding but does not confer oral stability.

Animal & human figures are kept visibly separate so studied animal doses are never misread as human guidance.

Sorted A–Z by vendor — never by price

Weekly median $/mg from the live vendor crawl.

Researched storefront prices, bucketed

p25 $5.00 · median $6.92 · p75 $8.00 · 6 researched vendors

Legit, COA-backed band: $4.50–$11.00/mg.

Value rule: don't just buy the cheapest — a price under $3/mg is a red flag. Pair price with COA and independent-test grade.

Estimated cost of research (10 mg)

Vial (best researched price)

$37

Bacteriostatic water (generic estimate)

$6

Syringes / supplies (generic estimate)

$12

What each test proves — general guidance, plus this compound's researched purity data

Independent labs cited for this compound

Buyer red-flag checklist

• No COA / in-house only
• Price < ~$3/mg
• Crypto-only payment
• No contact info
• No reship policy
• Old or photoshopped COA (> 6 mo)

GMP vs research-grade: the chemistry (SPPS + HPLC + MS) is identical — the difference is the quality system.

• An RUO label is not an import exemption — CBP judges actual intended use.
• Lyophilized powder is ambient-stable in transit; temperature control needed for > 7-day transit.
• US-warehouse vendors dodge import scrutiny — they cost more but ship more reliably.

Every item dated & sourced

No granted patents identified in current seed. Composition-of-matter coverage is limited given the peptide's synthetic origin.

• IACUC / IRB research context
• RUO buyer responsibilities & documentation
• Veterinary / alternative-use where lawful
• Jurisdiction-aware "who may lawfully obtain"

What people discuss

Reported concerns — discussion, not established effects

Reading caveats

• self-selection bias — positive responders more likely to post
• unsanctioned self-experimentation context — not clinical-trial population
• vendor-affiliated content present in aggregator pages (e.g. PeptideDeck ads)
• anecdotal self-report — no lab verification of dose/identity in most posts
• third-party testing often performed in China per user reports

Manually researched from reddit, youtube, x— theme weights are research estimates, not live counts; aggregated & de-identified. No individual posts, quotes, or usernames are ever shown.

Relative research / market volume — populated once the activity stream is wired

Inline tooltips for lyophilized, RUO, EU/mg, SPPS, 503A and more.

Toggle plain-language ↔ scientific in the header.

• How to read a COA
• Free base vs acetate
• Understanding evidence grades

Investigational synthetic 39-aa triple agonist (GLP-1R/GIPR/GCGR) from Eli Lilly in Phase 3 development for obesity and type 2 diabetes. Approximately 142 articles are indexed (literature last scanned 2026-05-29). US regulatory status: Investigational — no NDA filed as of mid-2026. Research use only.

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