Name: Retatrutide
Brand: PeptidesDirect
SKU: PD-RETATRUTIDE-20MG
Availability: InStock

Question 1

What is Retatrutide?

Accepted Answer

Retatrutide is a novel triple-agonist peptide that targets GLP-1, GIP, and glucagon receptors simultaneously. It is one of the most studied next-generation incretin peptides in metabolic research.

Question 2

How should I store Retatrutide?

Accepted Answer

Store lyophilized Retatrutide at -20°C for long-term storage or at 2-8°C for short-term use. Once reconstituted, keep refrigerated at 2-8°C and use within 30 days.

Question 3

What purity is your Retatrutide?

Accepted Answer

Every batch of Retatrutide ships with a certificate of analysis from Janoshik Analytical, an independent third-party laboratory, at a minimum purity of 99%. We do not run a lab ourselves: the manufacturer commissions this test, and we pass the report on unchanged, with an online verification link on the product page. This batch also carries a second, independent test from BT Labs, commissioned outside the manufacturer.

Question 4

How do I reconstitute Retatrutide?

Accepted Answer

Add bacteriostatic water slowly along the vial wall. Gently swirl until dissolved - never shake. Use 1-2 mL of bacteriostatic water per vial. Ensure the solution is clear before use.

Question 5

What is Retatrutide and how does its triple GLP-1/GIP/glucagon receptor mechanism work, according to the published research?

Accepted Answer

Retatrutide activates three separate incretin-system receptors at once: the GIP receptor, the GLP-1 receptor, and the glucagon receptor, which is why the phase 2 trials describe it as a triple hormone receptor agonist (Jastreboff AM et al, N Engl J Med 2023, PMID 37366315). GIP and GLP-1 receptor activity are proposed to slow gastric emptying and increase glucose-dependent insulin release, while the added glucagon receptor activity is proposed to raise energy expenditure, a mechanism component that GLP-1-only or GIP/GLP-1 dual agonists do not have. This is the receptor pharmacology described in the published trials, not a claim about what any product does in a person.

Question 6

What has Retatrutide actually been studied for (condition, model, species)?

Accepted Answer

Published trials have tested retatrutide in adults for obesity and weight-related conditions (phase 2, n=338, Jastreboff AM et al, NEJM 2023, PMID 37366315), for blood-sugar control in type 2 diabetes (phase 2, n=281, Rosenstock J et al, Lancet 2023, PMID 37385280), and for liver-fat reduction in MASLD (phase 2a substudy, n=98, Sanyal AJ et al, Nat Med 2024, PMID 38858523). A separate mouse study examined obesity-associated pancreatic and lung cancer progression (Marathe SJ et al, NPJ Metab Health Dis 2025, PMID 40094000). All three human trials are phase 2, mid-stage, industry-sponsored evidence; the cancer finding is preclinical, in mice only, and has not been tested in humans.

Question 7

What dose did the Retatrutide trials use (species, route, frequency, duration), and is there a published human dosing protocol?

Accepted Answer

The phase 2 obesity trial gave adult participants retatrutide by subcutaneous injection once weekly, escalating in stages up to a 12 mg maintenance dose, for 48 weeks (Jastreboff AM et al, N Engl J Med 2023, PMID 37366315). Because retatrutide has no FDA or EMA approval, that schedule was a research only regimen run under a clinical trial protocol with medical monitoring, not an approved or publicly recommended human dosing protocol: no such protocol exists for retatrutide. Separately, the earliest published animal work dosed mice at 30 nmol/kg per dose (about 0.14 mg/kg based on retatrutide's 4731.3 g/mol molecular weight), subcutaneously, every other day for about two weeks before tumor cell injection and continuing through tumor growth (Marathe SJ et al, NPJ Metab Health Dis 2025, PMID 40094000): that is a mouse research dose with no established human equivalent.

Question 8

What did the Retatrutide trials observe as the outcome, and how quickly did the effect appear?

Accepted Answer

At 48 weeks, participants on the highest studied dose (12 mg weekly) lost a mean 24.2% of body weight versus 2.1% on placebo, with clear separation from placebo already visible at 24 weeks (-17.5% on 12 mg) (Jastreboff AM et al, NEJM 2023, PMID 37366315). In the diabetes trial, HbA1c fell by up to 2.02 percentage points at 24 weeks on the 12 mg dose versus 0.01 points on placebo (Rosenstock J et al, Lancet 2023, PMID 37385280). In the MASLD substudy, liver fat fell by a mean 82.4% at 24 weeks on the 12 mg dose, with 86% of that group reaching normal liver fat (under 5%), versus 0% on placebo (Sanyal AJ et al, Nat Med 2024, PMID 38858523). These are trial endpoints reached by study participants under a research protocol, not outcomes we can promise from any vial we sell.

Question 9

What side effects or adverse events were reported in the Retatrutide trials, with rates and citations where available?

Accepted Answer

In the phase 2 obesity trial, gastrointestinal events (nausea, diarrhea, vomiting) were the most common adverse effect, dose related and mostly mild to moderate, and heart rate rose in a dose-dependent way that peaked around week 24 of the 48-week trial before declining (Jastreboff AM et al, NEJM 2023, PMID 37366315). In the type 2 diabetes trial, gastrointestinal events occurred in 35% (67 of 190) of retatrutide participants overall versus 13% on placebo and 35% on dulaglutide, with no severe hypoglycemia and no deaths reported (Rosenstock J et al, Lancet 2023, PMID 37385280). In the MASLD substudy, transient, generally mild-to-moderate gastrointestinal events were again the most frequent adverse events, more common at the 8 mg and 12 mg doses, though that trial's published text did not break the rate down per individual event (Sanyal AJ et al, Nat Med 2024, PMID 38858523). These are the adverse events as reported in each trial, not a claim that they are the only ones that could occur.

Question 10

What is not known about Retatrutide's long-term safety, i.e. what is the honest evidence gap?

Accepted Answer

All human evidence on retatrutide comes from phase 2 trials only, each 24 to 48 weeks long; no phase 3 result has yet been published in a peer-reviewed journal, so there is no long-term (multi-year) human safety data (Jastreboff AM et al, NEJM 2023, PMID 37366315; Rosenstock J et al, Lancet 2023, PMID 37385280; Sanyal AJ et al, Nat Med 2024, PMID 38858523). There is no published data in anyone under 18, no pregnancy or breastfeeding data, and no FDA or EMA approval for any indication as of July 2026. All three trials were sponsored by Eli Lilly and authored largely by its employees or Lilly-funded investigators, so an assumption of sponsorship bias applies until independent replication exists. That is the honest evidence gap: mid-stage, short-duration, single-sponsor data only, nothing more.

Question 11

Is Retatrutide approved by the FDA, EMA, or any regulator, or is it strictly an unapproved research compound?

Accepted Answer

No. Retatrutide is not approved by the FDA, the EMA, or any other medicines regulator for any use, and it remains an investigational compound with no New Drug Application filed as of July 2026. Eli Lilly's phase 3 obesity trial (TRIUMPH-1) reported topline results by press release in May 2026, and industry reporting places a possible NDA filing around Q4 2026, but a press release is not a submission and a submission is not an approval. Until any such approval happens, retatrutide can only be sold and purchased as a research chemical, never as a medicine.

Question 12

How much bacteriostatic water should be used to reconstitute a given vial size of Retatrutide, and does the ratio matter for stability?

Accepted Answer

The water volume used does not need to match an exact recipe across our 10 mg, 20 mg, 30 mg, and 50 mg vials: adding more or less bacteriostatic water only changes the final concentration (mg per mL) drawn up, it does not change the peptide's chemical stability. Retatrutide is a neutral-pH compound in the GLP-1 drug class, so standard bacteriostatic water, with no special pH-adjusted water, is appropriate for every vial size we carry. What actually governs stability once dissolved is temperature and time, not the water-to-peptide ratio, which is why refrigeration and a defined use-by window matter more than getting the milliliters exact.

Question 13

What does our own third-party CoA show for Retatrutide, and how can a specific batch be verified?

Accepted Answer

Our most recent Retatrutide batch (Blue, 20 mg) tested at 99.9% purity with 19.9 mg of peptide confirmed on content analysis, tested 18 April 2026 by BT Labs; that report is community-submitted, meaning a customer sent us that specific vial's lab result rather than us or the manufacturer commissioning it. We also carry manufacturer-commissioned reports from Janoshik for other batches, for example the 50 mg batch (Black Cap) at 99.81% purity and 56.06 mg content, tested 23 January 2026; Janoshik tests are paid for by the peptide manufacturer, not by us, and we disclose that source on every report rather than calling any of it independent testing. Every report carries a live verification link (verify.btlabtesting.com or verify.janoshik.com) so a specific batch and lot can be checked against the lab's own database instead of trusting a static PDF.

Question 14

How does Retatrutide compare to Tirzepatide in mechanism and trial evidence?

Accepted Answer

Both are incretin poly-agonists studied for obesity and type 2 diabetes, but tirzepatide activates two receptors (GIP and GLP-1) while retatrutide adds a third, the glucagon receptor, which researchers point to as the mechanistic driver of its larger measured effect sizes. A 2024 network meta-analysis of 27 randomized trials (15,584 patients) found retatrutide's higher doses produced more weight loss than tirzepatide's highest studied dose: -22.10% (12 mg) and -20.70% (8 mg) for retatrutide versus -16.53% for tirzepatide 15 mg (Xie Z et al, Metabolism 2024, PMID 39305981). No head-to-head randomized trial has put the two drugs in the same participants yet (one is underway, expected to report in December 2026); this is an indirect, pooled comparison across separate trials, not a direct one. Tirzepatide is an FDA-approved medicine (Mounjaro for diabetes since May 2022, Zepbound for weight management since November 2023); retatrutide has no such approval and remains investigational.

Question 15

Is "GLP-3" the same thing as Retatrutide, or is that a naming confusion?

Accepted Answer

No. "GLP-3" is not a real receptor or hormone in the published endocrine literature, and retatrutide does not act on anything by that name. The proglucagon gene produces glucagon, GLP-1, and GLP-2 (a distinct peptide studied for intestinal conditions, not weight or blood sugar); retatrutide's three confirmed targets are the GIP receptor, the GLP-1 receptor, and the glucagon receptor, as described in its phase 2 trials (Jastreboff AM et al, NEJM 2023, PMID 37366315). "GLP-3" appears to be a mix-up between that GIP/GLP-1/glucagon triple-agonist description and the real, unrelated GLP-2.

Question 16

Did the Retatrutide trials measure any effect on testosterone or other hormone levels?

Accepted Answer

No published retatrutide trial, including the phase 2 obesity, type 2 diabetes, or MASLD studies, reports testosterone or other sex-hormone data as an outcome (Jastreboff AM et al, NEJM 2023, PMID 37366315; Rosenstock J et al, Lancet 2023, PMID 37385280; Sanyal AJ et al, Nat Med 2024, PMID 38858523). A PubMed search for retatrutide together with testosterone or sex hormones returns no original research at all, only unrelated editorial correspondence. That is a genuine evidence gap, not a "no effect" finding: the trials were not designed to measure it, so the published record cannot say either way.

Question 17

Did the Retatrutide trials measure any effect on blood pressure or heart rate?

Accepted Answer

Heart rate rose in the phase 2 obesity trial in a dose-dependent way, peaking around week 24 of the 48-week trial and then declining (Jastreboff AM et al, NEJM 2023, PMID 37366315). Blood pressure itself was pooled across published retatrutide trials in a 2026 meta-analysis, which found a mean 6.79 mmHg reduction in systolic and 2.46 mmHg reduction in diastolic blood pressure (Simental-Mendía LE et al, High Blood Press Cardiovasc Prev 2026, PMID 42371360). So the trial record shows two separate cardiovascular signals, a transient heart-rate rise and a net blood-pressure fall, reported from different analyses, not something attributable to any vial we sell.

Question 18

Did any published Retatrutide trial test a split or divided weekly dose, or only a single weekly dose?

Accepted Answer

No. Every published human trial, the phase 2 obesity, type 2 diabetes, and MASLD studies, dosed retatrutide once weekly by subcutaneous injection; none tested a split or twice-weekly schedule (Jastreboff AM et al, NEJM 2023, PMID 37366315; Rosenstock J et al, Lancet 2023, PMID 37385280; Sanyal AJ et al, Nat Med 2024, PMID 38858523). That single weekly injection design tracks retatrutide's roughly 6-day mean half-life, which a pharmacokinetic review states supports once-weekly dosing (Tetelbaun L et al, Cardiol Rev 2024, PMID 39724554). No published research has compared a divided dose against the once-weekly schedule, so there is no trial evidence either way on whether splitting the same weekly total would change anything.

Question 19

How does Retatrutide compare to Semaglutide in mechanism and trial-reported weight-loss data?

Accepted Answer

Semaglutide is a single-receptor GLP-1 agonist, while retatrutide is a triple agonist acting on the GLP-1, GIP, and glucagon receptors, the added glucagon-receptor activity being the mechanistic addition researchers cite for retatrutide's larger measured effect sizes. In retatrutide's own phase 2 trial, the 12 mg dose produced a mean 24.2% body-weight reduction at 48 weeks versus 2.1% on placebo (Jastreboff AM et al, NEJM 2023, PMID 37366315). Semaglutide's pivotal phase 3 trial reported a mean 14.9% reduction at 68 weeks on its 2.4 mg dose versus 2.4% on placebo (Wilding JPH et al, NEJM 2021, PMID 33567185). No head-to-head randomized trial has tested both drugs in the same participants, so this remains an indirect, cross-trial comparison. Semaglutide (Wegovy, Ozempic) is FDA-approved and EMA-authorized; retatrutide has no such approval and remains investigational.

Question 20

How long does Retatrutide solution last, and how should it be stored, once it has been reconstituted?

Accepted Answer

Unopened, lyophilized Retatrutide is stable refrigerated (2-8C), and freezing extends that shelf life further, so keep the sealed vial cold, dark, and dry until you are ready to reconstitute it. Once mixed with bacteriostatic water, keep the vial refrigerated at 2-8C, protected from light, and avoid repeated freeze-thaw cycles: each cycle risks degrading the peptide. As with the other GLP-1-class compounds we carry, a reconstituted Retatrutide solution holds for a matter of weeks, not months, so treat it as a research reagent with a defined use-by window rather than an indefinitely stable stock solution, and never refreeze it once it has thawed.

Question 21

Is Retatrutide banned by WADA, or would it show up on a standard drug test?

Accepted Answer

No. Retatrutide does not appear on WADA's Prohibited List, so its use is not currently an anti-doping violation in or out of competition. WADA's Monitoring Program, which tracks non-prohibited substances for misuse patterns rather than banning them, added semaglutide markers in 2024 and expanded to tirzepatide markers from January 2026; retatrutide, which has no FDA or EMA approval and remains investigational, is not named on that public monitoring list either. Standard workplace or general drug-screening panels test for illicit drugs of abuse such as opioids, amphetamines, and cannabinoids, not peptide compounds like retatrutide, so it would not show up on one. WADA reviews its lists annually, so this status can change; this is regulatory information, not medical or doping advice.

Question 22

Does Retatrutide cause a distinctive tingling or numbness sensation (dysesthesia) not seen with Semaglutide or Tirzepatide, and how common is it by dose?

Accepted Answer

Yes. Cutaneous sensory events are a documented retatrutide signal: the 2023 phase 2 obesity trial reported cutaneous hyperesthesia in 7% of retatrutide participants versus 1% on placebo, and the phase 3 TRIUMPH program reported it more prominently, and broken out by dose, as dysesthesia (tingling, numbness, or altered skin sensation). In the TRIUMPH-1 obesity trial (topline results by press release, May 2026), dysesthesia was reported in 5.1% of participants on 4 mg, 12.3% on 9 mg, and 12.5% on 12 mg, versus 0.9% on placebo; a separate osteoarthritis trial (TRIUMPH-4) reported higher rates, 8.8% on 9 mg and 20.9% on 12 mg, versus 0.7% on placebo. Lilly describes the events as mostly mild to moderate, generally resolving on treatment. Semaglutide's and tirzepatide's published trials do not report a comparable signal at meaningful rates, so it appears relatively specific to retatrutide among the incretin agonists. As with the rest of the TRIUMPH program, these are announced topline figures, not yet a peer-reviewed publication.

Question 23

Does Retatrutide research show lean-mass loss alongside fat loss, the way other GLP-1-class peptides do?

Accepted Answer

Yes. The phase 2 obesity trial assessed body composition by DEXA in a subset of participants and found that both fat mass and lean mass declined, with fat mass making up the larger share of the weight lost, a pattern the literature describes as broadly typical of GLP-1-class agents (Jastreboff AM et al, NEJM 2023, PMID 37366315). That is a trial-subject finding recorded under a supervised research protocol, not a statement about lean-mass outcomes for anyone using a vial we sell, and the analysis did not isolate diet or exercise as separate variables, so it cannot be read as guidance on preserving muscle while losing weight.

Question 24

Is it legal to buy or possess Retatrutide as a research chemical in the EU, given it has no marketing authorization?

Accepted Answer

Retatrutide is sold and marketed by us exclusively as an unapproved research chemical for in-vitro laboratory use, never for human or animal consumption, and it carries no FDA, EMA, or other regulatory approval for any indication. Rules on possessing, importing, or ordering unapproved research compounds differ by EU member state and can change, so we cannot state one legal conclusion that covers every country we ship to. Buyers are responsible for checking their own country's import and research-substance regulations before ordering; nothing here is legal advice, and none of it authorizes use in a person or animal.

Question 25

Does Retatrutide's known pharmacology (delayed gastric emptying) create a documented interaction risk with other orally absorbed compounds, such as oral contraceptives?

Accepted Answer

Published pharmacology describes GIP, GLP-1, and glucagon receptor agonists, the mechanism class retatrutide belongs to, as slowing gastric emptying, and the drug-labeling literature for approved GLP-1-class medicines notes that a slower stomach can alter how quickly a co-administered oral compound is absorbed, oral contraceptives included. That is a general pharmacological mechanism reported in the literature for the drug class, not medical or contraceptive guidance, and no retatrutide trial specifically tested an oral-contraceptive interaction or measured contraceptive efficacy. Anyone with a medical question about drug interactions should direct it to a licensed physician or pharmacist, not to a vial sold for research use only.

Question 26

Has Retatrutide been studied in combination with Cagrilintide or other GLP-1-class peptides, and is there published data on stacking?

Accepted Answer

No published clinical trial has tested retatrutide together with cagrilintide, an amylin analogue, or any GLP-1-class peptide, in the same participants; retatrutide's trial evidence comes entirely from single-agent studies (Jastreboff AM et al, NEJM 2023, PMID 37366315). Claims about combined or "stacked" use circulating online extrapolate from those separate single-agent results, which is not the same as a trial that dosed the combination and measured what happened. We do not provide a combined-use protocol or dosing schedule for any peptide combination, and GLP-1-class medicines available by prescription are regulated pharmaceuticals in the EU, a status separate from the research-use-only compounds we sell.

Retatrutide

What is Retatrutide

How it works

Often studied alongside

Documentation

Storage and stability

Frequently Asked Questions

Technical data sheet

Frequently bought together

AOD-9604

Tesamorelin

Bacteriostatic Water

Lab Measuring Syringe + Prep Wipes Set (1 mL 31G)

Graduated Measuring Syringe 1 mL 31G x 6 mm

Alcohol Prep Pads 30 x 65 mm

Peptide Storage Box (10 Compartments)

Peptide Vial Case 30 Slots