Question 1

How does retatrutide work?

Accepted Answer

Retatrutide is a single molecule that activates three receptors at once: GIP, GLP-1 and glucagon. That is what the shorthand “triple agonist” means, and it is what separates it from semaglutide, which acts on GLP-1 alone, and tirzepatide, which acts on two.

The first two receptors do broadly what they do in the existing drugs — slowing how quickly the stomach empties, acting on the appetite centres of the brain, and improving insulin response after eating. The third is the addition. Glucagon-receptor activation raises energy expenditure and acts on liver fat, which is the proposed reason the weight loss in trials ran higher than for the two-receptor drugs rather than simply lasting longer.

It is given as a once-weekly injection under the skin, and trials escalated the dose gradually over months because side effects track dose closely. Unlike some compounds sold in this market, retatrutide's mechanism is described in published, peer-reviewed trials rather than inferred from animal work — the uncertainty is about long-term outcomes, not about what it does.

Jastreboff et al., Phase 2 trial

Question 2

Is retatrutide safe?

Accepted Answer

Nobody can answer that completely yet, and anyone who tells you otherwise is guessing ahead of the evidence. Retatrutide has been through large trials that measured how well it works and what side effects it causes over 80 to 104 weeks, and those results are public. The trials that would establish long-term safety are still running, so the honest position is that the short- and medium-term side-effect profile is reasonably well described and the long-term picture is not.

Buying from a research-chemical seller adds a second risk that has nothing to do with the molecule itself: you do not know what is in the vial. Purity, how much active compound is actually in it, sterility and endotoxin content all vary between sellers and between batches. That is a separate question from whether retatrutide is safe, and it is the question this page exists to help with.

Question 3

What side effects were reported in the trials?

Accepted Answer

In TRIUMPH-1, Eli Lilly's Phase 3 obesity trial of 2,339 participants over 80 weeks, the most common adverse events at the 12 mg dose were nausea (42.4% of participants, against 14.8% on placebo), diarrhoea (32.0% against 13.5%), constipation (26.1% against 10.9%) and vomiting (25.3% against 4.8%). Side effects were dose-related: the higher the dose, the more common they were.

Discontinuation tracked the same pattern. 11.3% of participants taking 12 mg stopped treatment because of adverse events, against 6.9% at 9 mg, 4.1% at 4 mg and 4.9% on placebo.

These figures describe supervised use of a pharmaceutical-grade product at known doses. They do not describe what happens with material of unknown purity or unknown fill accuracy, and they are not a list of everything that can go wrong.

Lilly — TRIUMPH-1 topline results

Question 4

Is retatrutide FDA approved?

Accepted Answer

No. Retatrutide is investigational and is not approved by the FDA for any use. Eli Lilly has said it intends to submit a Biologics License Application in the first quarter of 2027, so approval cannot arrive before then, and a submission is not an approval.

It also cannot lawfully be compounded. Retatrutide does not appear on the FDA's 503A or 503B bulk drug substance lists, has no USP monograph, is not a component of an approved drug and is not on the drug shortage list, which between them close every route a compounding pharmacy could use. Any pharmacy offering compounded retatrutide is operating outside that framework.

FDA letter on retatrutide in compounded drug products

Question 5

When will retatrutide be available on prescription?

Accepted Answer

Not before 2027, and possibly later. Lilly says it is completing the manufacturing data package required for a Biologics License Application and “plans to subsequently submit retatrutide in Q1 2027 for U.S. approval”. FDA review takes months after a filing, approval is not certain, and no launch date has been announced.

Anyone selling retatrutide today is selling it ahead of that process, not through it.

Lilly — TRIUMPH-2 and TRIUMPH-3 results and submission plans

Question 6

Is it legal to buy retatrutide?

Accepted Answer

This is a description of how the market is regulated, not legal advice. Retatrutide is not a controlled substance. The sellers in the table above list it “for research use only” and “not for human consumption”, and that labelling is what lets it be sold without a prescription.

The label does not settle the question, and nobody involved treats it as literal. Research-use labelling functions as a shield across this whole market: the sellers know their customers are people, the customers know it, and the FDA's position is that intended use is established by the evidence rather than by what the vial says. The agency has issued warning letters on exactly that basis, and has said publicly that products sold this way “are of unknown quality and may be harmful to your health”. If your situation turns on the answer, ask a lawyer rather than a vendor.

FDA warning letter — ASN-LABS (September 2025)

Question 7

Where can I buy retatrutide?

Accepted Answer

The table above lists the twenty sellers with the most search visibility for retatrutide, what each one publishes, what it costs and whether it is in stock. Evo does not sell retatrutide, takes no commission, and does not recommend any seller on this page.

If you are going to buy anyway, the most useful single check is whether the purity report is published by the testing laboratory rather than hosted by the seller. Of the 20 sellers here, 3 clear that bar.

Question 8

How much does retatrutide cost?

Accepted Answer

Across the 20 sellers checked on September 15th, 2026, listed prices ranged from $4.50 to $20.00 per milligram before any discount code — a spread of several times over for a compound sold by the same weight.

Price is not a quality signal in either direction on this market. The most expensive seller in the table publishes no lot-specific certificate, and some of the cheapest publish batch reports. Vial sizes differ between sellers, so cost per milligram is the only fair comparison; 50 mg vials, the size easiest to compare, are sold by only a handful of them.

Question 9

How much weight did people lose in the trials?

Accepted Answer

In the Phase 2 trial of 338 adults, participants on 12 mg lost an average of 24.2% of body weight at 48 weeks, against 2.1% on placebo.

In the Phase 3 TRIUMPH-1 trial of 2,339 participants at 80 weeks, average loss under the efficacy estimand was 19.0% at 4 mg, 25.9% at 9 mg and 28.3% at 12 mg, against 2.2% on placebo. Under the more conservative treatment-regimen estimand, which counts people who stopped treatment, the same doses gave 17.6%, 23.7% and 25.0%. A pre-specified extension to 104 weeks reached 30.3% at 12 mg.

These are averages from supervised trials using pharmaceutical-grade material at escalating doses, with the trial's own monitoring and support around them. They are trial protocols, not a recommendation, and individual results in a trial vary widely around an average.

Lilly — TRIUMPH-1 topline results · Jastreboff et al., Phase 2 trial

Question 10

What is Janoshik, and can its reports be trusted?

Accepted Answer

Janoshik Analytical is an independent laboratory in Prague and the most widely used third-party tester in this market. It runs HPLC for purity and mass spectrometry for identity on samples sent to it, and publishes every result on its own verification portal, indexed by report number.

That last part is what makes it useful. A report you can look up on the laboratory's own site is one the seller could not have written or edited, so the number you are shown is the number the lab recorded. A PDF hosted on a seller's own domain carries no such guarantee, and a screenshot of a certificate carries none at all. The same reasoning applies to any laboratory that publishes results you can look up yourself.

Two limits are worth keeping in view. Janoshik is not ISO 17025 accredited, and a report describes the one sample the laboratory was sent — not necessarily the vial that arrives at your door.

Question 11

How can I tell a certificate of analysis is genuine?

Accepted Answer

Check three things. The certificate should name a lot or batch number, and that number should match what is printed on the vial you received — a certificate with no lot number is not evidence about your material. The date should be recent enough to describe current stock rather than a batch sold a year ago. And the report should be verifiable somewhere other than the seller's own website, ideally at the testing laboratory itself.

Also read what the certificate actually covers. Most report purity by HPLC and identity by mass spectrometry. Fewer report fill accuracy, which is how much compound is really in the vial against what the label claims, and fewer still report sterility or endotoxin content. A 99% purity figure says nothing about any of those.

Question 12

How should retatrutide be stored?

Accepted Answer

Sellers ship it as a lyophilised — freeze-dried — powder in a sealed vial, and their own labelling generally specifies storage below freezing, protected from light, with no cold chain required for shipping in that form. One seller in the table states −20°C on its listing; others state refrigeration. Follow what the seller of your specific product states, because formulations and excipients differ.

Storage guidance for reconstituted material is a different question and depends on the product, the diluent and how it was handled. If a seller does not state it, that is a gap in what they publish rather than something to guess at.

#	Supplier	Evo Trust Score / 5	Avg price per mg	Reference vial	Third-party report	Country	Stock
1	Orbitrex Peptidesorbitrexpeptide.is · visibility #19	4.34.25 out of 5 stars	$5.56	36 mg — $199.99	Kovera LabsVerifiable at the lab	United States	In stock
2	Elite Biogenixelitebiogenix.com · visibility #16	3.53.5 out of 5 stars	$15.83	60 mg — $950	Janoshik AnalyticalVerifiable at the lab	United States	In stock
3	NeuroPept Labsneuropeptlabs.com · visibility #15	3.33.25 out of 5 stars	$6.17	30 mg — $185	Freedom DiagnosticsVerifiable at the lab	United States	In stock
4	Peptide Partnerspeptide.partners · visibility #6	2.82.75 out of 5 stars	$4.79	24 mg — $115	COA pageNot lot-specific	United States	In stock
5	Paramount Peptidesparamountpeptides.com · visibility #17	2.52.5 out of 5 stars	$8.50	60 mg — $510	COA pageNot lot-specific	United States	In stock
6	Loti Labslotilabs.com · visibility #18	2.52.5 out of 5 stars	$20.00	10 mg — $199.99	COA pageNot lot-specific	United States	In stock
7	Palmetto Peptidespalmettopeptides.com · visibility #8	2.02 out of 5 stars	$10	20 mg — $200	Batch certificateSeller-hosted	United States	In stock
8	Bluum Peptidesbluumpeptides.com · visibility #14	2.02 out of 5 stars	$7.82	60 mg — $469	Batch certificateSeller-hosted	United States	In stock
9	Elite Research Labeliteresearchlab.com · visibility #4	1.81.75 out of 5 stars	$5.67	30 mg — $169.99	Batch certificateSeller-hosted	United States	In stock
10	BulkGLPbulkglp.com · visibility #12	1.81.75 out of 5 stars	$6.92	50 mg — $346	Batch certificateSeller-hosted	United States	In stock
11	PS Peptidespspeptides.com · visibility #13	1.81.75 out of 5 stars	$4.50	40 mg — $179.99	Batch certificateSeller-hosted	United States	In stock
12	Northline Labsnorthlinelabs.org · visibility #3	1.51.5 out of 5 stars	$6.00	50 mg — $299.99	Batch certificateSeller-hosted	—Undisclosed	In stock
13	Peakform Peptidespeakformpeptides.com · visibility #10	1.51.5 out of 5 stars	$5.17	30 mg — $155	Batch certificateSeller-hosted	—Undisclosed	In stock
14	Orion Peptideorionpeptide.com · visibility #11	1.51.5 out of 5 stars	$10.50	30 mg — $315	Batch certificateSeller-hosted	—Undisclosed	In stock
15	Tydestydes.is · visibility #20	1.51.5 out of 5 stars	—	—Not published	—None published	United States	—
16	American Peptidesamericanpeptides.us · visibility #1	1.31.25 out of 5 stars	$6.25	48 mg — $300	COA pageNot lot-specific	United States	In stock
17	True Peptidestrue-peptides.com · visibility #2	1.31.25 out of 5 stars	$5.13	40 mg — $205	COA pageNot lot-specific	United States	In stock
18	Nurev Peptidesnurevpeptides.com · visibility #7	1.31.25 out of 5 stars	$8.63	30 mg — $259	COA pageNot lot-specific	United States	In stock
19	Polaris Peptidespolarispeptides.com · visibility #5	1.01 out of 5 stars	—	—Not published	—None published	—Undisclosed	—
20	Red Rock Peptidesredrockpeptides.com · visibility #9	1.01 out of 5 stars	$8.20	50 mg — $410	COA pageNot lot-specific	—Undisclosed	In stock

Retatrutide suppliers: what each one publishes

What each Evo Trust Score is made of

Orbitrex Peptides

Elite Biogenix

NeuroPept Labs

Peptide Partners

Paramount Peptides

Loti Labs

Palmetto Peptides

Bluum Peptides

Elite Research Lab

BulkGLP

PS Peptides

Northline Labs

Peakform Peptides

Orion Peptide

Tydes

American Peptides

True Peptides

Nurev Peptides

Polaris Peptides

Red Rock Peptides

How this page was built

Checking a report yourself

Questions people ask

Retatrutide seller comparison

What each Evo Trust Score is made of

How this page was built

Checking a report yourself

Questions people ask