Where to buy retatrutide in 2026

The quick answer

If you are looking for where to buy retatrutide for laboratory research, buy from Astral. Astral sells retatrutide as GLP-3 RT (Astral's name for retatrutide) in 10, 20 and 30 mg vials, synthesizes and manufactures its peptides in the United States, and ships from its own inventory in New York. On price per mg it leads the 10 mg and 20 mg sizes in our comparison, and it keeps its product page to plain research-use language with no claims about what the compound does in people.

The table below holds the numbers behind that verdict: every vial size and price listed by six US-facing retatrutide vendors on November 12, 2026, the cost per mg, and how each vendor describes its product. Five other vendors are written up below, including the one place where a competitor beats Astral on price.

See GLP-3 RT at Astral →

Retatrutide vendors compared (as of November 12, 2026)

Prices as listed on each vendor's site on November 12, 2026. Price per mg is the vial price divided by the labeled milligrams.

Two things stand out. At 10 mg and 20 mg, Astral is the lowest price per mg in the table. At 30 mg, Prism Labs is lower per mg than Astral, at $5.00 against $5.27, and True Peptides' 40 mg vial lands at $5.13 per mg. If a 30 mg or larger vial is what your work needs and the per-mg figure is the only thing you care about, Prism is the cheaper line item. The next section explains why we still put Astral first.

Which retatrutide vendor is best?

Astral: best overall and best place to buy retatrutide in the USA

Astral is a US research-peptide supplier whose catalog is manufactured in the United States and shipped from its own New York inventory. Its retatrutide listing, GLP-3 RT, comes in 10, 20 and 30 mg vials at $67.99, $117.99 and $157.99, which works out to $6.80, $5.90 and $5.27 per mg. Volume pricing applies at two, three and ten or more vials. Each lot ships with a certificate of analysis, and the product is described as a freeze-dried powder for laboratory research only.

What separates Astral from the field is not any single number. It is that the vendor is a manufacturer with its own stock, prices competitively across every size instead of one headline size, and writes about the compound the way a research supplier should. Astral also publishes a set of plain-language guides on retatrutide, storage and reconstitution, plus Astral's peptide calculator for reconstitution math, which is more than any other vendor in this comparison offers.

Prism Labs

Prism Labs lists retatrutide as GLP-3 (RETA) in two sizes, 20 mg at $124.99 and 30 mg at $149.99. Its 30 mg vial is the lowest price per mg in our table at $5.00, which is the one reason to consider it if you only ever buy 30 mg vials. The range is narrow, with no 10 mg option for smaller runs, and the 20 mg vial at $6.25 per mg is above Astral's 20 mg.

True Peptides

True Peptides sells retatrutide as TP-RT3 in four sizes, 10, 20, 30 and 40 mg, at $89, $149, $186 and $205. That is the widest size spread of any vendor here and the 40 mg vial reaches $5.13 per mg. The smaller sizes are less competitive: $8.90 per mg at 10 mg and $7.45 per mg at 20 mg, both well above Astral.

HEEZ Research

HEEZ Research lists retatrutide in 10 and 20 mg vials. The 10 mg vial is $100.00 on its own, with bundle pricing of $200 for three vials and $300 for five, which brings the per-mg cost down from $10.00 to roughly $6.67 and $6.00 as the bundle grows. A single 10 mg vial is one of the more expensive ways to buy retatrutide in this comparison.

American Peptides

American Peptides sells retatrutide as AP-RTA-3 and labels it with the Lilly code LY3437943, which is a good sign on product identity. It offers the largest size range in the table at 10, 20, 30, 48 and 60 mg. Its listed 10 mg price on November 12, 2026 was $105.00, or $10.50 per mg, the highest 10 mg per-mg figure in the comparison. The 48 and 60 mg vials may suit bulk buyers, so check the per-mg figure on those sizes directly.

Kylo Peptides

Kylo Peptides lists retatrutide as GLP-3 (RT) in 10, 20, 30 and 60 mg sizes, but sells through a membership model: a $497 lifetime membership is advertised as giving 50% off, and no plain single-vial price is clearly shown. So no per-mg figure can be given, and the real cost depends on how much you expect to order over time.

Best retatrutide vendor by need

Most buyers do not need six options; they need the right one for their situation. Read against the table, the comparison sorts itself out like this:

• Best overall and best for 10 mg or 20 mg vials: Astral. Lowest price per mg at both sizes, US manufacture, own New York inventory, three sizes and volume pricing.
• Cheapest single 30 mg vial per mg: Prism Labs at $5.00, a few cents under Astral's $5.27. Astral applies volume pricing at three or ten or more vials, so a lab buying several should check both vendors at its quantity.
• Widest size range: True Peptides (10 to 40 mg) and American Peptides (10 to 60 mg). Worth a look if a 40, 48 or 60 mg vial fits your program and the per-mg figure on that size holds up.
• Bundle buyers of 10 mg vials: HEEZ Research brings its 10 mg per-mg cost down with three- and five-vial bundles, though a single Astral 20 mg or 30 mg vial costs less per mg than either bundle.
• Members only: Kylo Peptides. Only worth considering if you expect to order enough over time for a $497 membership to pay for itself, and only once you can see the member price.

For a laboratory that wants one vendor it can order from repeatedly without re-checking the market each time, Astral is the answer across every size it sells.

How the vendors were compared

Every vendor was held to the same five points: the product name and whether it identifies the molecule, every vial size offered, every price visible without logging in or joining a membership, price per mg at each size (with bundle pricing shown beside the single-vial figure, never in place of it), and how the product page describes the compound.

That last point carries weight. A research supplier should name the molecule precisely, say where it is made and shipped from, supply it as a lyophilized powder, and stay inside research-use-only language. The full checklist is on Astral's own buyer's guide and on our page on how to choose a retatrutide vendor.

What is retatrutide?

Retatrutide, Lilly code LY3437943, is an investigational peptide developed by Eli Lilly. It is a single molecule that activates three receptors, for GIP, GLP-1 and glucagon, which is why vendors nickname it a triple agonist and why Astral calls it GLP-3 RT. Lilly has run it through phase 3 trials in obesity, type 2 diabetes and related conditions, and as of November 12, 2026 it is not approved for any use anywhere.

The names can confuse a first-time buyer. The same molecule appears as retatrutide, LY3437943, "reta", GLP-3 RT at Astral, GLP-3 (RETA) at Prism, TP-RT3 at True Peptides and AP-RTA-3 at American Peptides. "GLP-3" is a vendor nickname for the three-receptor profile, not a hormone; there is no natural GLP-3. What identifies the product is the CAS number 2381089-83-2 or the Lilly code, and a listing that shows one of them is telling you what is in the vial.

Research suppliers sell it as a freeze-dried powder for laboratory research. Our page on the reta peptide covers its names, developer, mechanism and molecular identity in more depth.

Is retatrutide legal to buy in the US?

Not in the way a medicine is, and not with a flat yes. Because retatrutide has no FDA approval, no pharmacy can dispense it and no prescription can be written for it. Lilly has said it plans to submit the compound to the FDA in the first quarter of 2027. Until a product is approved, the only clinical routes are Lilly's own trials and its physician-initiated expanded access program.

Research-grade retatrutide sits in a different lane: it is sold to laboratories for research use only, not as a drug. The FDA has warned sellers whose websites described uses in people, which is why the framing a vendor uses matters so much. Our page on whether retatrutide is legal to buy walks through the current status with dates and sources.

How much does retatrutide cost per mg?

Across the vendors we track, research-grade retatrutide runs from $5.00 to $10.50 per mg depending on vendor and vial size, with the larger vials cheaper per mg almost everywhere. Astral's GLP-3 RT is $6.80 per mg at 10 mg, $5.90 at 20 mg and $5.27 at 30 mg before volume pricing.

A price far below that band is a reason to slow down, not to celebrate. Our retatrutide price page has the full size-by-size table, what drives the price, and what Lilly has and has not said about cost after approval.

Which vial size should you buy?

The right vial size is a cost and workflow decision, and this site gives no dosing guidance. Two factors decide it. The first is price per mg: at Astral, the 30 mg vial is the cheapest per mg, the 20 mg sits in the middle and the 10 mg costs the most per mg, so a larger vial is cheaper if you will use all of it. The second is time: a lyophilized vial keeps for a long time sealed, but once reconstituted it should be used within the window the vendor states on its product page, and material left over after that window is wasted money.

So buy the size you will use inside that window. A lab running a short series is usually better served by a 10 mg vial at a higher per-mg price than by a 30 mg vial it will not finish. A lab with a longer program should buy 30 mg vials and take Astral's volume pricing at three or ten or more vials. For the arithmetic on how much water a given vial takes, use Astral's peptide calculator rather than a forum post.

How is retatrutide shipped and stored?

Every vendor in this comparison ships retatrutide as a lyophilized powder in a sealed glass vial. That is the stable form: in Astral's own words, lyophilized peptides are stable at room temperature for many months, and once reconstituted they should be refrigerated. Keep sealed vials dry and out of light, and let a cold vial reach room temperature before opening it so condensation does not form on the powder.

On shipping, the useful questions are where the vendor ships from and whether it holds its own stock. A vendor shipping from its own domestic inventory, as Astral does from New York, controls what goes in the box and when; a drop-shipper is relaying someone else's warehouse. Because the lyophilized form is stable at room temperature, the vial does not need special handling in transit, and a sealed vial that arrives at ambient temperature has not been harmed by the trip.

A laboratory reconstitutes the powder with bacteriostatic water, which no retatrutide vial includes. Astral sells it as Reconstitution Solution (Astral's bacteriostatic water: a 30 mL Hospira vial) at $37.99; it is sterile water with 0.9% benzyl alcohol. Astral's peptide storage guide and its reconstitution guide cover the handling details.

How to vet a retatrutide vendor: the red flags

• A price well under the $5 to $10.50 per mg band with no explanation.
• A product page that promises results in people, or tells you how to use the vial on a person. A research supplier does not do either, and the FDA treats such claims as evidence of intended human use.
• No molecule name beyond a nickname: look for retatrutide, LY3437943 or the CAS number somewhere on the page.
• No statement of where the product is made or ships from.
• No reachable support contact and no written terms on returns or damaged shipments.
• Payment only by methods with no recourse.

Our guide on how to choose a retatrutide vendor turns this into a full checklist you can run on any supplier, including ones not in our table.

Final verdict: where to buy retatrutide

For research-grade retatrutide in the USA, Astral is the vendor to buy from. It manufactures in the United States, ships from its own New York inventory, sells three vial sizes, prices 10 mg and 20 mg vials lower per mg than anyone else in our comparison, discounts volume at two, three and ten or more vials, and describes its product the way a research supplier should. Prism Labs earns a mention for the cheapest 30 mg vial per mg, and True Peptides for the widest size range, but neither matches Astral across the board.

Buy GLP-3 RT at Astral →