How to Enroll in a Retatrutide Clinical Trial in 2026

How to Enroll in a Retatrutide Clinical Trial in 2026

Key takeaways:

• Retatrutide is only available through clinical trials. It is not FDA-approved and cannot be prescribed.
• Eli Lilly's TRIUMPH Phase 3 program includes 7+ active trials across obesity, diabetes, MASH, sleep apnea, and cardiovascular outcomes.
• Most trials require BMI 30+ (or 27+ with a weight-related health condition). Additional criteria vary by trial.
• ClinicalTrials.gov is the primary tool for finding and contacting active trial sites.
• You may receive a placebo instead of the active drug. This is a fundamental part of clinical trial design.
• If clinical trials are not an option, FDA-approved alternatives exist now: semaglutide and tirzepatide.

Important: This article is for informational purposes only. It is not medical advice. Retatrutide is an investigational compound not approved by the FDA. Always discuss clinical trial participation with your healthcare provider. See our full medical disclaimer.

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Why clinical trials are the only legitimate access

As of March 2026, there is no prescription for retatrutide. No pharmacy dispenses it. No telehealth provider can prescribe it. The drug has not received FDA approval for any indication.

The only way to receive pharmaceutical-grade retatrutide under medical supervision is through a clinical trial.

Products sold online as "retatrutide" are unregulated research chemicals with no verified purity, potency, or sterility. We do not recommend self-administering investigational compounds obtained outside of clinical settings.

For the full timeline on when retatrutide might become available as a prescription, see our retatrutide guide and FDA approval timeline analysis.

Current trial status: the TRIUMPH program

Eli Lilly's Phase 3 program for retatrutide is called TRIUMPH. It is a large, multi-trial program studying the drug across several conditions.

Active TRIUMPH trials

NCT05882045 (Obesity + Knee Osteoarthritis): This was the first Phase 3 trial to report results (February 2026). It showed 28.7% weight loss and 75.8% reduction in knee pain. This trial has likely completed enrollment.

NCT06383390 (Primary Obesity Trial): The main weight management study. This is the trial most likely to support the FDA submission for an obesity indication. Results expected mid-to-late 2026. May still have enrolling sites.

Type 2 Diabetes Trials: Separate Phase 3 studies are testing retatrutide for glycemic control. If you have type 2 diabetes and obesity, these trials may be an option.

MASH/NASH Trial (TRIUMPH-3): Testing retatrutide for metabolic liver disease. The Phase 2 data showed approximately 82% liver fat reduction at the highest dose. If you have diagnosed MASH or significant liver fat, this trial targets your condition directly.

Sleep Apnea Trial: Studying whether the weight loss from retatrutide improves obstructive sleep apnea severity.

Cardiovascular Outcomes Trial: A longer-term study measuring heart attack, stroke, and cardiovascular death. This trial runs for years and may still be enrolling.

Trial status changes frequently. New sites open. Enrollment caps are reached. The information above reflects what was publicly available as of early 2026.

How to search for trials on ClinicalTrials.gov

ClinicalTrials.gov is the U.S. National Library of Medicine's database of clinical studies. It is the authoritative source for trial information.

Step-by-step process

Step 1: Go to ClinicalTrials.gov. Navigate to clinicaltrials.gov in your browser.

Step 2: Search for retatrutide. In the search bar, enter "retatrutide" or the drug's research designation "LY3437943." Both terms will return relevant results.

Step 3: Filter by recruiting status. Use the filters on the left side to select "Recruiting" or "Not yet recruiting." Trials marked "Completed" or "Active, not recruiting" are no longer accepting new participants.

Step 4: Filter by location. You can narrow results by country, state, or city. TRIUMPH trials are running at medical centers across the United States, Europe, and other countries.

Step 5: Review eligibility criteria. Click on any trial to see the full details. The "Eligibility" section lists every inclusion and exclusion criterion. Read these carefully before contacting a site.

Step 6: Contact the study site. Each trial listing includes contact information for participating centers. This is usually a phone number or email for the study coordinator. Reach out to ask about current enrollment availability.

Typical eligibility criteria

Eligibility varies by trial, but most retatrutide obesity trials share common requirements.

Common inclusion criteria

• Adults aged 18-75 (some trials have narrower ranges)
• BMI of 30 or higher (obesity) OR BMI of 27+ with at least one weight-related health condition (hypertension, dyslipidemia, type 2 diabetes, sleep apnea, etc.)
• Stable body weight (not currently on another weight loss medication or program)
• Willing to comply with the study schedule (regular visits, blood draws, monitoring)

Common exclusion criteria

• Recent weight loss surgery (bariatric surgery within the last 12 months, sometimes longer)
• Current use of other weight loss medications (GLP-1 agonists like semaglutide or tirzepatide, phentermine, etc.)
• History of pancreatitis
• Personal or family history of medullary thyroid carcinoma or MEN2 syndrome
• Significant cardiovascular event within the last 6 months
• Active eating disorder
• Pregnancy or plans to become pregnant during the study period
• Certain psychiatric conditions or recent psychiatric hospitalization

These criteria exist to protect participant safety and ensure clean data. Some are negotiable. Some are absolute.

If you are currently taking semaglutide or tirzepatide, you will likely need a washout period (stopping the medication for a defined period) before enrolling. Discuss this with your doctor and the trial coordinator.

What to expect as a participant

Clinical trial participation is a significant commitment. Here is what a typical Phase 3 obesity trial involves.

Screening period (2-8 weeks)

Before you are officially enrolled, you will go through screening. This includes medical history review, physical exam, blood work, and potentially imaging studies. The trial team verifies you meet all eligibility criteria.

Treatment period (48-72+ weeks)

Once enrolled, you will receive either the study drug (retatrutide at various doses) or a placebo injection. This is randomized. You will not know which you are receiving, and neither will your clinical team. This is called "double-blinding."

The injection is typically weekly, self-administered at home after initial training. You will visit the clinical site periodically (usually every 4-12 weeks) for assessments, blood draws, and safety monitoring.

Follow-up period (varies)

After the treatment period ends, most trials include a follow-up period where you are monitored but no longer receiving the drug. This helps researchers understand what happens after treatment stops.

The placebo question

This is the part most people do not want to hear: you may receive a placebo.

Most Phase 3 obesity trials are placebo-controlled. Depending on the trial design, there may be a 25-50% chance of receiving an inactive injection instead of retatrutide. You will not know which group you are in until the trial concludes.

This is fundamental to clinical science. Without placebo controls, there is no way to distinguish drug effects from natural variation and the placebo effect. It is not negotiable.

If you are unwilling to accept the possibility of receiving a placebo, clinical trial participation may not be the right choice. FDA-approved options like semaglutide and tirzepatide are guaranteed active medication.

Compensation and costs

Clinical trial participation is generally free. You should not have to pay for the study drug, study-related office visits, lab work, or medical procedures that are part of the trial protocol.

Many trials also provide:

• Compensation for time and travel (varies by site, often $50-200 per visit)
• Reimbursement for transportation costs
• Free study drug and supplies (injection devices, alcohol swabs, etc.)

You should never pay to participate in a legitimate clinical trial. If a site asks for payment, that is a red flag.

Insurance is generally not billed for study-related care, but you should clarify this with the trial coordinator during screening. Medical care for conditions unrelated to the study remains your responsibility.

Questions to ask the trial coordinator

When you contact a study site, ask these questions:

1. Is this trial currently enrolling new participants? Sites sometimes appear as "recruiting" on ClinicalTrials.gov even after they have reached their enrollment target.
2. What is the randomization ratio? This tells you the probability of receiving the active drug vs placebo.
3. What is the visit schedule? How often do you need to come in? Can some visits be done remotely?
4. What is the total time commitment? Including screening, treatment, and follow-up.
5. What happens if I experience significant side effects? Trials have safety protocols. You should understand them before enrolling.
6. Can I leave the trial at any time? The answer should always be yes. You can withdraw at any time for any reason.
7. Will I find out which group I was in after the trial? Most trials offer unblinding after completion.
8. Is there an extension study? Some trials offer open-label extensions where all participants receive the active drug after the blinded period ends.

Alternatives while waiting

If clinical trial participation is not practical, FDA-approved options exist today.

Tirzepatide (Zepbound/Mounjaro)

Tirzepatide is the closest currently available option to retatrutide. It is a dual agonist (GLP-1 + GIP) that produces about 22% average weight loss. FDA-approved for both weight management (Zepbound) and type 2 diabetes (Mounjaro). Available by prescription now.

Semaglutide (Wegovy/Ozempic)

Semaglutide is a single GLP-1 agonist with about 15% average weight loss. It has the longest safety track record of any GLP-1 obesity medication and also reduces cardiovascular events by 20% (SELECT trial). Available by prescription now.

Comparison resources

• Retatrutide vs Tirzepatide: Which is better?
• Tirzepatide vs Retatrutide data comparison
• Semaglutide vs Retatrutide data comparison
• Best peptide for weight loss in 2026
• Peptides for weight loss: complete guide

The treatment landscape is moving fast. If the TRIUMPH results continue to be positive, retatrutide could be available as a prescription within 18-24 months. For the latest on the approval process, see our retatrutide FDA approval date analysis and the complete retatrutide guide.

FAQ

How do I sign up for a retatrutide clinical trial?

Search ClinicalTrials.gov for "retatrutide" and filter by "Recruiting" status. Review the eligibility criteria for each trial. Contact the listed study sites to ask about enrollment availability. Discuss participation with your personal healthcare provider before committing.

Will I definitely get retatrutide if I enroll?

No. Most Phase 3 trials are placebo-controlled. You may be randomized to receive a placebo injection instead of the active drug. The probability depends on the trial's randomization ratio, which is typically 1:1 or 2:1 (active:placebo).

Can I enroll if I am currently taking semaglutide or tirzepatide?

Most trials require a washout period where you stop other weight loss medications before enrollment. The length of the washout varies by trial. You should not stop any medication without consulting your prescriber first.

Do I need a referral from my doctor?

Not always. You can contact trial sites directly. However, your doctor's involvement is strongly recommended. They can help you evaluate whether the trial is appropriate for your health situation and manage any washout from current medications.

What happens after the trial ends?

After the blinded treatment period, some trials offer an open-label extension where all participants receive the active drug. If no extension is offered, you return to your regular healthcare provider. You cannot continue receiving retatrutide outside of a trial until it receives FDA approval.

Are there retatrutide trials near me?

Trial sites are located at major medical centers across the United States and internationally. ClinicalTrials.gov lets you filter by location. Larger metropolitan areas generally have more participating sites.

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Medical Disclaimer: The information on this website is for educational and informational purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before deciding to participate in a clinical trial. Individual eligibility varies. See our full medical disclaimer.

Sources

1. Jastreboff, A.M., et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity." New England Journal of Medicine, 2023. PMID: 37385275
2. NCT05882045: Retatrutide in Obesity with Knee Osteoarthritis. ClinicalTrials.gov
3. NCT06383390: Retatrutide for Obesity (TRIUMPH). ClinicalTrials.gov
4. U.S. Food and Drug Administration. "The Drug Development Process." FDA.gov. Updated 2024.
5. ClinicalTrials.gov. "Eli Lilly TRIUMPH Program." National Library of Medicine.