When Will Retatrutide Be FDA Approved? The Q1 2027 Filing Timeline

For most of 2026, the answer buyers heard was “by the end of the year.” Lilly had put retatrutide on its list of medicines that might go to the FDA before 2026 was out, and the phase 3 results kept arriving: six positive trials between December 11, 2025 and October 28, 2026, the last of them a head-to-head win over Ozempic.

Then the date moved. On July 23, Lilly said the application would reach the FDA in the first three months of 2027, after it finishes the manufacturing section the agency reads alongside the trials. The clinical data were already done. What’s left is the filing, a review that runs eight to twelve months on the FDA’s own clock, and a launch that took Lilly weeks, not months, on its last two weight-loss drugs.

Simms Research stocks it now as a research powder, Retatrutide (GLP-3), sized from 10mg up to 60mg, and six of its batches have been through an independent ISO-certified lab.

Is retatrutide FDA approved

No. As of October 30, 2026, no regulator anywhere has approved retatrutide, and Lilly hasn’t filed it with the FDA yet. Lilly’s October 28 release still describes it as an investigational molecule “that has not been approved by FDA or any regulatory organization anywhere in the world.”

What Lilly does have is a finished clinical package. Its August 5 earnings release called the data complete for registrations worldwide in three uses: obesity, moderate-to-severe obstructive sleep apnea and knee osteoarthritis pain. Type 2 diabetes runs on its own track, the TRANSCEND trials, whose third study was still running on the trial registry in October 2026.

The UK, Canada, Europe and Australia wait on the same data. Lilly has said the package supports submissions around the world but has given a date only for the US one. How retatrutide got here, from receptor to trials, is told in What Is GLP-3.

When will retatrutide be FDA approved

Most likely between January and March 2028. With priority review the window moves up to September to November 2027.

Both come from the FDA’s published clock. The agency takes 60 days to accept a new application, then aims to decide within 10 more months on a standard review or 6 on a priority one, so the decision lands about 12 or 8 months after the application arrives:

The fastest row has a Lilly precedent. Foundayo, Lilly’s weight-loss pill, held one of the FDA’s national priority vouchers and was approved on April 1, 2026, 50 days after filing, the fastest approval of a new molecule since 2002. Lilly hasn’t announced a voucher or priority review for retatrutide, and the FDA settles the review type when it accepts the application, so early 2028 is the base case and the autumn of 2027 the fast one.

The clock can also stretch. A major amendment sent in during the review lets the FDA push its goal date back three months, which would move a standard decision into the spring of 2028.

Why Lilly delayed the retatrutide filing to 2027

To finish the manufacturing file. The trials weren’t the reason.

Early in 2026, Lilly grouped retatrutide with the medicines that might be submitted before the year was out. On July 23, the day TRIUMPH-2 and TRIUMPH-3 read out, it named the first quarter of 2027 instead, saying it was completing the chemistry, manufacturing and controls package a biologic application needs. It told reporters it needed more time to gather manufacturing and quality-control data for the agency.

That section is the half of an application buyers never see: how the drug is made at commercial scale, how each batch is tested before release, and how long it holds up on the shelf. The FDA reads it as closely as the weight-loss results, so Lilly is finishing it before the application goes in. The trial side was finished by August 5, when Lilly called the clinical package complete, and it repeated the first-quarter 2027 date then and again on September 29.

Retatrutide FDA approval timeline

Six trials in, the evidence is in hand; what remains is the submission and the review.

TRIUMPH-5 is the last big readout before the filing. It puts retatrutide up against tirzepatide, the molecule behind Zepbound and Mounjaro, and the trial registry lists its main phase finishing in November 2026. Lilly called the clinical package complete without it, so it adds a comparison rather than a requirement. Where the two stand on the published numbers so far is in retatrutide vs tirzepatide, and the newer amylin drug Lilly is testing beside them is covered in eloralintide vs retatrutide.

What the retatrutide FDA review will weigh

Not whether it works. Six positive trials settle that; the questions sit with the top dose and how people tolerate it.

In TRIUMPH-1, 12mg brought an average 28.3% weight loss at 80 weeks, and 11.3% of people on it stopped over side effects, compared with 4.9% on placebo. Nausea, the most common one, affected 42.4% against 14.8%. The 4mg dose gives reviewers a gentler rung: 19.0% weight loss with a single dose step, and fewer people stopping than on placebo, 4.1% against 4.9%.

Dysesthesia, an odd prickling or heightened sensation in the skin, is the side effect that sets retatrutide apart from tirzepatide. It reached 12.5% on 12mg against 0.9% on placebo, was mostly mild to moderate, and most people who had it kept taking the drug. The side effects women ask about most are covered in side effects of retatrutide for women.

Heart safety rests on TRIUMPH-3 for now: 44 major cardiovascular events among people on retatrutide and 52 on placebo over 80 weeks. The 10,000-person outcomes trial reads out in 2029, after the first decision; Zepbound was approved in 2023 the same way, before its own outcomes trial had finished.

When will retatrutide be available in the US

Within weeks of approval, going by Lilly’s last two launches.

Zepbound was approved on November 8, 2023 and reached US pharmacies on December 5, 27 days later. Foundayo was approved on April 1, 2026, and LillyDirect, Lilly’s own online pharmacy, began shipping it on April 6. On the review clock above, that puts the first retatrutide prescriptions in late 2027 at the earliest and most likely in the first half of 2028.

Before then, the prescription route runs through the trials still enrolling and Lilly’s expanded access program, which takes requests from a treating doctor one patient at a time. Who qualifies and how a request works are covered in retatrutide early access.

How much will retatrutide cost

Lilly hasn’t set a price. The two weight-loss drugs it already sells direct show how it prices them: a monthly self-pay figure that steps up with the dose and levels off near the top.

Miss the 45-day refill window and Zepbound’s higher doses list at $499 to $699 a month. Those are the prices retatrutide would launch beside.

Research supply is priced by the vial instead. Here is four weeks of each step on the trial ladder, priced from Simms Research’s Retatrutide (GLP-3) vials:

A prescription pays for the clinician, the pharmacy and a ready-to-use product. A vial price covers powder only, which gets mixed with Research Water ($20 for 10mL) and measured out with the retatrutide calculator. Simms Research’s July 16, 2026 batch tested 99.611% pure and held 10.68mg against a 10mg label, and the five batches before it are listed under retatrutide lab results.

What the timeline means for buyers

The filing is a few months off and the approval about a year after it. Lilly submits retatrutide between January and March 2027. The FDA’s standard clock then puts a decision in early 2028, priority review brings it to the autumn of 2027, and Lilly’s recent launches put the drug in pharmacies within a month of either.

Until then, research supply is where most buyers meet it. Simms Research’s Retatrutide (GLP-3) starts at $84 for 10mg; an order in by 5PM Eastern leaves that day, and the Free Delivery Guarantee covers a parcel lost, stolen after a delivery scan or damaged. The retatrutide dosage chart has the units for each step, and Tirzepatide (GLP-2) sits with the other compounds in the shop.

Frequently asked questions

Has Lilly submitted retatrutide to the FDA yet?

No. Lilly plans to submit its application between January and March 2027, once its manufacturing and quality data are complete.

Will retatrutide be approved in 2026?

No. The application goes in during 2027, and the FDA’s review runs months after that, so the first possible decision falls in 2027 and the likeliest in early 2028.

Is retatrutide approved in the UK or Canada?

No regulator anywhere has approved it. Lilly plans submissions outside the US on the same trial data and hasn’t given dates for them.

Does Lilly’s dispute with the FDA delay retatrutide?

Not on Lilly’s stated plan. Lilly and the FDA disagree over whether retatrutide counts as a biologic, a case a federal appeals court heard on September 24, 2026, and Lilly plans to file a biologic application in the first quarter of 2027 either way.

Is Simms Research legit?

Its retatrutide has six published certificates from an independent ISO-certified lab, the newest dated July 16, 2026, each one open to read. Same-day dispatch runs to a 5PM Eastern cutoff, the Free Delivery Guarantee applies to every parcel, and the support line, 855-592-8507, is staffed 9AM to 5PM Eastern on weekdays, with email at support@simmsresearch.com. No discount code or affiliate link appears on this page.