How to Get Retatrutide in 2026: FDA Approval Status and Clinical Trials

Retatrutide is not FDA approved, and no other country has approved it either (checked October 19, 2026). Lilly says it will file for FDA approval in the first quarter of 2027. Until then, how to get retatrutide comes down to two legal routes: a clinical trial, or Lilly’s expanded access program, which is limited to a small group of patients and has to be requested by a doctor.

Quick answer

The legal way to get retatrutide right now works like this:

1. Search ClinicalTrials.gov for “retatrutide” and “LY3437943”.
2. Filter to recruiting studies near you and read who can join.
3. Contact the study site and book a screening visit.
4. If you can’t join a trial and have severe obesity with serious complications, ask your doctor about Lilly’s expanded access program.
5. Keep a record of each dose, any side effects and your weight.

Step 5 is where Regimen comes in: a free peptide tracker app for your dose schedule, side effects, weight and resting heart rate.

Is Retatrutide FDA Approved?

No. Retatrutide is an investigational drug from Eli Lilly. It hasn’t been approved by the FDA or by any other regulator, so a doctor can’t prescribe it and a pharmacy can’t fill it. There is no list price, no insurance coverage and no regulated supply.

It’s often called a “GLP-3” because it acts on three hormone receptors instead of one or two:

• GLP-1: the gut hormone semaglutide (Ozempic, Wegovy) copies. It slows digestion and cuts appetite.
• GIP: a second gut hormone, which tirzepatide (Mounjaro, Zepbound) adds.
• Glucagon: a hormone that tells the body to burn stored energy. This is the new part.

When Will Retatrutide Be Available?

For retatrutide FDA approval, Lilly has said it will file its application in the first quarter of 2027. It had earlier planned to file by the end of 2026, and moved the date to finish its manufacturing and quality-control data (BioPharma Dive, July 23, 2026, reporting Lilly’s comments to CNBC). Lilly hasn’t given an approval date. Any date you see is a guess.

The filing rests on Lilly’s retatrutide trials, called TRIUMPH:

• TRIUMPH-1, the main obesity trial, reported in May 2026: 28.3% average weight loss at 80 weeks on the 12 mg dose.
• TRIUMPH-4, in people with obesity and knee arthritis, reported in December 2025.
• TRIUMPH-2 (type 2 diabetes) and TRIUMPH-3 (heart disease) reported in July 2026.
• TRIUMPH-5, the first trial to compare retatrutide with tirzepatide directly, finishes late in 2026.

So is retatrutide available? Only inside a study or the expanded access program, until the FDA approves it.

Step 1: Find a Retatrutide Clinical Trial

Retatrutide clinical trials are the main legal route, and they’re public: Lilly’s retatrutide trials are listed on ClinicalTrials.gov, the National Library of Medicine’s registry.

1. Go to ClinicalTrials.gov and search the drug name, “retatrutide”. Then search again for “LY3437943”, Lilly’s code name for it: some listings only use the code.
2. Set the study status to “Recruiting” or “Not yet recruiting”. Finished studies won’t take you.
3. Enter your city or ZIP code to see a retatrutide clinical trial near you. Each listing names its study sites.
4. Open the eligibility section. It lists who can join (age, BMI, conditions) and who can’t (for example some medical histories or current medications).
5. Use the contact on the listing to reach the site directly.

Lilly also lists its own studies at trials.lilly.com.

What Enrolling in a Trial Involves

A screening visit comes first: a medical history, a physical, blood tests and a check against the eligibility list. If you qualify, you sign a consent form that explains the study, its visits and its risks.

Many retatrutide trials compare it with a placebo, so you may not get the drug, and you won’t know which you’re on. You’d also follow the study’s dose plan, not your own. In TRIUMPH-1, everyone on retatrutide started at 2 mg once a week and stepped up every four weeks until they reached their assigned dose. Ask the site what the study pays for and how often you’d need to come in.

Step 2: Lilly’s Expanded Access Program

Expanded access lets a patient who can’t join a trial get an unapproved drug through their own doctor. Lilly runs one for retatrutide, listed on ClinicalTrials.gov as NCT07629401, and it’s narrow. From Lilly’s medical information page (last reviewed August 26, 2026), a patient has to:

• Be 18 or older.
• Have obesity that hasn’t responded to treatment: a BMI of 35 or higher despite taking and tolerating the highest available dose of a weight-management drug.
• Have two or more serious or life-threatening obesity-related complications that are being treated.
• Be unable to join an ongoing retatrutide trial or a comparable one.
• Have discussed standard options, including bariatric surgery, with their doctor.

Only the treating physician can ask, not the patient. The doctor calls the Lilly Answers Center (1-800-545-5979), fills in Lilly’s intake form, and if the request is approved, signs an agreement, applies to the FDA as the sponsor and gets ethics board approval. Lilly supplies the drug at no cost. Availability depends on where you live and on supply, and expanded access ends once retatrutide is approved and on sale.

What About Retatrutide Sold Online?

Many people taking retatrutide today aren’t in a trial. They buy it online, where it’s sold as a research peptide: a freeze-dried powder in a small vial, usually labeled “for research use only”. It isn’t an approved drug, and it can’t legally be compounded, so there’s no pharmacy version either. In August 2026 the FDA sent one seller a warning letter calling its retatrutide an unapproved new drug.

If you’re reading up on it, these are the practical differences from a prescription:

• Nobody independent checks the vial. Quality depends on the seller. Some sellers post lab test results, but those come from the seller, not from a regulator.
• You do the dose math. The powder is mixed with bacteriostatic water and drawn up with an insulin syringe, so each dose depends on how many milligrams the vial holds and how much water went in. The same mark on the syringe means a different dose in a different vial. The retatrutide reconstitution calculator works out the units for your vial and water amount.
• There’s no safety net. If a batch is bad, there’s no recall and no manufacturer to report it to.

Why Trial Doses Start Low

The trial dose plans are slow on purpose. In TRIUMPH-1, every retatrutide group started at 2 mg and stepped up every four weeks. In the earlier trial behind it, starting at 2 mg instead of 4 mg partly reduced the stomach side effects, and resting heart rate rose with the dose, peaked around week 24 and eased after that. That’s why people keep a record of each dose and how they feel at each step.

If You’re Already on Retatrutide: What to Track

Whether you’re in a trial or not, a written record is what you and your doctor will work from. Track four things:

• Every dose: the date, the amount in mg, and the units you drew on the syringe.
• Side effects: nausea, constipation, reflux, fatigue and injection-site reactions, each with the day and how bad it was.
• Resting heart rate: the trend over weeks, not a single reading.
• Weight: weekly, same time of day.

Among Regimen users on a weekly retatrutide shot, nausea is most often logged the day after the injection, about twice as often as on shot day, and it usually fades by day 6. Appetite is at its lowest about two days after the shot.

For what each side effect looks like and when it shows up, see the retatrutide side effects guide. For the trial dose steps, see the retatrutide dosing guide, and if you’re coming from tirzepatide, the tirzepatide to retatrutide switching guide. The heart rate rise has its own page: retatrutide and heart rate.

Track Retatrutide With Regimen

Regimen is a free peptide tracker app that covers all four:

• Dose schedule: custom scheduling with dose titration. Enter the plan (2 mg for four weeks, then the next step) and every dose lands on the right day with a reminder that says how much to take.
• Reconstitution calculators: vial size and water in, the exact units to draw on any syringe out.
• Side effects and 50+ daily markers: nausea, constipation, appetite, energy, sleep and injection-site reactions, each logged against the dose you were on.
• Weight and health metrics: weight, body fat, resting heart rate, blood pressure and sleep, plus half-life tracking that shows where your level sits between shots.
• Pattern detection: watches your doses, markers and weight, measured against your own baseline. Steve Carter put it this way in a Google Play review: “It caught the HR increase from Reta before I did.”
• Share-with-provider report: a PDF of your doses, side effects and weight for your next appointment.

Free for one compound, no time limit; Premium if you track more than one. It’s on iPhone and Android: App Store and Google Play.

Before You Start

Everything on this page about approval, filing dates and the expanded access program comes from Lilly, the FDA or ClinicalTrials.gov, and it can change, so check those pages for the latest. Nothing here recommends taking retatrutide, a dose or a place to get it. Retatrutide’s long-term safety is still being studied, so talk to a doctor before you start.

Sources

• Approval status and compounding: FDA warning letter to Peptide Partners LLC, August 24, 2026 and FDA, Concerns with Unapproved GLP-1 Drugs Used for Weight Loss (content current as of October 1, 2026).
• Filing timeline: BioPharma Dive, July 23, 2026.
• TRIUMPH-1 results and dose steps: Eli Lilly, May 21, 2026. Earlier trial: Jastreboff et al., New England Journal of Medicine, 2023.
• Expanded access: Lilly Medical, Is there an expanded access program for retatrutide? (last reviewed August 26, 2026) and ClinicalTrials.gov NCT07629401.
• Trials: ClinicalTrials.gov and Lilly Trials.

All sources checked October 19, 2026. This article is for education and tracking. It is not medical advice.