Retatrutide has no list price because it is not approved, and the only legal route, Lilly's expanded access program, is free. On the gray market the monthly cost depends on the dose step in the trials: 8 mg per four weeks at 2 mg a week, rising to 48 mg at 12 mg a week. At the $8.50/mg median of the listings we logged in May and June 2026, that is $68 to $408 per four weeks.
Retatrutide has no price because nobody is allowed to sell it to you. Eli Lilly's triple agonist is still investigational. Lilly says it will file with FDA in Q1 2027, and its expanded access program supplies the drug free to a narrow group of patients. Everything else is the research-peptide market, where we logged listings from $6.27 to $29.99 per mg in May and June 2026.
Monthly cost is milligrams times price per milligram. The milligrams come from the dose steps Lilly used in its Phase 3 trials. The price comes from vendor catalogs. Both inputs move, so we show the arithmetic.
How much does retatrutide cost per month?
In TRIUMPH-2, participants "initiated treatment with 2 mg once weekly and increased the dose in a stepwise approach every four weeks," per Lilly's 29 September 2026 release. The 12 mg arm stepped 2, 4, 6, 9, then 12 mg. The 9 mg arm stopped at 9 and the 4 mg arm at 4.
We price each step per four-week block (four weekly doses). Multiply by 1.086 for a calendar month.
| Weekly dose in trial | mg per 4 weeks | At $6.27/mg (lowest listing) | At $8.50/mg (median) | At $12.18/mg (upper listing) |
|---|---|---|---|---|
| 2 mg | 8 | $50 | $68 | $97 |
| 4 mg | 16 | $100 | $136 | $195 |
| 6 mg | 24 | $150 | $204 | $292 |
| 9 mg | 36 | $226 | $306 | $438 |
| 12 mg | 48 | $301 | $408 | $585 |
The price columns come from our peptide price index: 16 retatrutide listings from 5 US and EU research vendors, vial sizes 5 to 50 mg, captured between 9 May and 25 June 2026. The median is $8.50 per mg. The lowest single listing was $6.27 (a 50 mg vial). We used $12.18 as the upper column because it is the next price up after one vendor's small-vial premium, where 5 mg and 10 mg vials ran $29.99 and $17.99 per mg.
These prices are three to five months old. Since we captured them, Lilly sued six sellers and FDA sent five warning letters to others (see the August letters and lawsuits), and several vendors have closed or pulled pages. Treat the columns as a scale, not a quote.
Over a year the totals add up quickly. Stepping to 12 mg over 16 weeks and holding it for the remaining 36 weeks is 516 mg: about $3,235 at the lowest listing, $4,386 at the median and $6,285 at the upper column. Holding at 9 mg instead is 408 mg ($3,468 at the median). Holding at 4 mg is 200 mg ($1,700).
These numbers leave out shipping, reconstitution supplies, vial loss and any retesting. They also assume the vial holds what the label says, which is the assumption that most often fails.
Why does the per-mg price understate the real cost?
The index divides price by the milligrams printed on the label. What matters is milligrams of retatrutide actually in the vial, and a lab measures that separately from purity.
A vial that holds more than its label lowers the effective price. The one retatrutide test in our Janoshik mirror that matches an index vendor measured 5.79 mg in a 5 mg vial, which cuts the effective cost per mg by about 14%.
A vial that holds less raises it. Our vendor failure taxonomy documents a 50 mg SS-31 vial that measured 44.10 mg, an 11.8% under-fill. Applied to retatrutide at the $8.50 median, that gap means an effective $9.64 per mg.
A vial with the wrong molecule, or none, costs its full price for zero milligrams. That outcome dominates every column in the table above, and only a lot-specific test can rule it out.
Why do retatrutide prices vary so much between vendors?
Three drivers show up in our index.
Vial size. Per-mg price falls as vials get larger. One vendor charged $29.99 per mg on a 5 mg vial and $8.66 on a 30 mg vial of the same product. Another priced every size from 10 to 50 mg at a flat $8.50.
Channel. The 16 listings above are retail research vendors with US or EU storefronts. Factory-direct sellers price far lower. Finnrick's retatrutide leaderboard showed one vendor at $1.23 per mg on 25 September 2026. That is a different channel with different risks: international shipping, customs seizure and less recourse.
What the price claims to include. Some vendors attach a lot-specific certificate from an outside lab; some post a generic one; some post nothing. A certificate costs a vendor a few hundred dollars per lot. A Janoshik GLP-1 blind test lists at $360 (testing labs compared). Spread over a large lot, that adds pennies per mg.
A post in r/longevity claimed "The cheapest vendor just tested purer than vendors charging 3x more" (thread). The same text appeared from a second account five days later and promoted a price-index site, so we read it as seeded marketing rather than a buyer report.
What will retatrutide cost once approved?
Nobody has said. Lilly's September release gives a Q1 2027 BLA target and no price. We found no projection from a named analyst or from Lilly. Until a price is announced, any branded figure is a guess.
What we can say is where approval changes the math. An approved product comes as a dosed pen with a fixed price per pen, not a per-mg vial. Insurance coverage, manufacturer savings programs and Lilly's direct-to-patient channels would decide what a patient pays, as they do for tirzepatide today. Compare the compounds themselves in retatrutide vs tirzepatide.
What is the legal route, and what does it cost?
There is exactly one outside a trial, and it is free.
Lilly's pre-approval single-patient expanded access program is registered as NCT07629401 (record updated 6 August 2026). Per Lilly Medical:
- The patient must be 18 or older with a BMI of 35 or more despite adherence to the highest available dose of approved weight-management therapy.
- The patient needs two or more serious or life-threatening obesity-related complications and must be unable to join a trial.
- The treating physician applies, becomes sponsor of an individual IND with FDA, gets IRB approval and handles storage and dispensing.
- "Direct to patient shipping is not available from Lilly."
- "Lilly provides products at no cost through the expanded access program."
There is no compounded route. FDA has stated retatrutide "cannot be used in compounding under federal law," as quoted in Lilly's August complaints, and a compounding pharmacy is one of the six defendants Lilly sued. Our where-to-buy page covers the access question in full.
Is cheaper retatrutide more likely to fail testing?
Our data cannot answer this yet, and we would rather say so than imply a trend.
Only one of the five vendors in the price index has a retatrutide test in our Janoshik mirror (99.7% purity, 5.79 mg measured on a 5 mg label, April 2026). Most retatrutide certificates in our Kovera registry do not name the vendor, so we cannot join them to prices.
The broader Kovera data shows why vendor-published certificates cannot settle the price question. Our Kovera mirror (retrieved 2 August 2026) holds 274 retatrutide certificates, counting code-named products and blends. Of the 272 with a purity figure, the median is 99.88%. One record shows 0%, meaning no retatrutide detected, and every other record sits between 98.67% and 99.99%. Vendors choose which batches to send, so these numbers describe the batches vendors were willing to publish. They say nothing about the vials that were never tested.
Buyer reports point the other way. In September, one r/PeptidePathways reply read "Purchased 4 kits of reta and had it test as Sema" (thread), and a gray-market tirzepatide vial came back "No Analyte Detected" (thread). If a vial labelled retatrutide holds something else, its price per mg of retatrutide is infinite. That is the most common reason a low monthly cost turns out not to be one; see retatrutide not working for how buyers tell a bad vial from a non-response.
Do RUO vendors charge more because they test?
A thread asked, "I don't really understand the hate for RUO companies because they cost more" (r/PeptidePathways). The price itself tells you nothing. What you can check is whether the vendor publishes a certificate for the lot you receive, whether that certificate resolves on the issuing lab's own server, and whether the lot number on your vial matches. A vendor that passes all three has earned some of its markup. A vendor that charges more and passes none has not. Our Kovera vendor leaderboard ranks vendors by what their published certificates show.
What we read
Our price index snapshots for retatrutide (16 listings, 5 vendors, captured 9 May to 25 June 2026); Lilly's TRIUMPH-2 release of 29 September 2026; the ClinicalTrials.gov record and Lilly Medical page for NCT07629401; Lilly's August 2026 complaints; finnrick.com's retatrutide leaderboard on 5 October 2026; our Janoshik and Kovera mirrors; Reddit threads on r/longevity and r/PeptidePathways.
What we did not read
Current vendor prices after 25 June 2026; we did not refresh the index for this piece. Any analyst forecast of branded retatrutide pricing. Prices from med spas or telehealth sellers offering retatrutide, which Lilly's suits target.
Sources
- vialaudit peptide price index, retatrutide listings captured 9 May to 25 Jun 2026
- Eli Lilly, TRIUMPH-2 release, 29 Sep 2026
- ClinicalTrials.gov, NCT07629401, updated 6 Aug 2026
- Lilly Medical, retatrutide expanded access, reviewed 26 Aug 2026
- Eli Lilly v. Legendary Peptides, complaint, 12 Aug 2026
- Finnrick, retatrutide leaderboard, 25 Sep 2026
- r/longevity, cheapest-vendor post
- r/PeptidePathways, RUO pricing thread
Frequently asked
How much does retatrutide cost per month?
There is no approved product, so no list price. Research-vendor listings we logged in May and June 2026 ran $6.27 to $29.99 per mg, median $8.50. At the median, the trial dose steps cost about $68 per four weeks at 2 mg a week and $408 at 12 mg a week, before shipping and losses.
Is retatrutide available legally?
Only through clinical trials or Lilly's single-patient expanded access program (NCT07629401). A treating physician must apply, the patient needs a BMI of 35 or more despite the highest available approved therapy plus two serious obesity-related complications, and Lilly supplies the drug at no cost. Compounding retatrutide is not lawful.
How much will retatrutide cost when it is approved?
Lilly has not announced a price. It plans to submit a Biologics License Application to FDA in the first quarter of 2027, according to its 29 September 2026 release. Any figure you see for a branded price today is a guess, and we found no projection from a named source.
Why is gray-market retatrutide cheaper than Mounjaro?
No trials, no approval costs, no cold chain you can audit, and no guarantee the vial holds what the label says. One buyer quoted in Lilly's August 2026 complaints said ten 20 mg vials cost "about half the cost of a single 7.5mg Mounjaro pen". Lilly sued six sellers partly on that diversion argument.
Is cheaper retatrutide more likely to fail testing?
Our data cannot answer that yet. Only one vendor in our price index has a retatrutide test in our lab mirrors. The vendor-submitted Kovera certificates we hold for retatrutide have a 99.88% median purity across every price point, which reflects which batches vendors choose to test.
Do RUO vendors cost more because they test?
Sometimes, but price is not evidence of testing. Ask for the lot-specific certificate, resolve it on the lab's own site and match the lot on your vial. A higher price with no verifiable certificate buys you nothing a cheaper unverified vial does not.