Retatrutide in the Philippines: research, safety and status

What it is

Retatrutide is an investigational medicine made by Eli Lilly for obesity and type 2 diabetes. Its research code is LY3437943.

Investigational means it is still being tested. No regulator approval was found in the sources checked. Lilly describes it as "an investigational molecule that cannot be legally sold or marketed for human use."

It has been tested in phase 2 and phase 3 randomized, placebo-controlled trials in adults with obesity and in adults with type 2 diabetes.

How it works

Retatrutide acts on three hormone receptors at once. It is a single peptide that activates the GIP (glucose-dependent insulinotropic polypeptide) receptor, the GLP-1 (glucagon-like peptide-1) receptor and the glucagon receptor.

For comparison, semaglutide acts on the GLP-1 receptor and tirzepatide acts on the GIP and GLP-1 receptors. Retatrutide adds the glucagon receptor, which is why it is called a triple agonist.

In clinical trials it was given as a once-weekly injection under the skin.

What the research shows

This page covers seven trials with published or company-reported results. The five peer-reviewed trials were funded by Eli Lilly. Two phase 3 results (TRIUMPH-3 and TRIUMPH-4) come only from Lilly press releases and had not been peer reviewed in the sources checked.

The mg figures below are trial group labels used to report results. They are not dosing guidance.

Other findings from these trials:

• Phase 2 obesity trial: at 48 weeks, 100% of the 12 mg group lost 5% or more of body weight, 93% lost 10% or more and 83% lost 15% or more, versus 27%, 9% and 2% with placebo.
• Knee osteoarthritis: in 574 TRIUMPH-1 participants with knee osteoarthritis, WOMAC pain scores changed by -3.4, -3.9 and -4.1 versus -2.5 with placebo. In TRIUMPH-4 (treatment-regimen estimand), Lilly reported changes of -4.0 and -3.7 points versus -2.1 with placebo.
• Sleep apnea: in 243 TRIUMPH-1 participants with obstructive sleep apnea, breathing pauses per hour (apnea-hypopnea index) changed by -22.8, -34.3 and -32.1 versus -9.6 with placebo.
• Heart events: in TRIUMPH-3, Lilly reported 44 MACE-5 events with retatrutide versus 52 with placebo (hazard ratio 0.82, 95% CI 0.55 to 1.22) and 27 MACE-3 events versus 23 (hazard ratio 1.12, 95% CI 0.64 to 1.96). Events were fewer than anticipated in all groups. These are not peer-reviewed results.

Side effects and risks

The most common side effects of retatrutide in trials were gastrointestinal. In the phase 2 obesity trial they were dose-related and mostly mild to moderate.

Other risks recorded in the trials:

• Heart rate: in the phase 2 obesity trial, heart rate rose with dose, peaked at 24 weeks and declined after that.
• Stopping because of side effects: in TRIUMPH-1, Lilly reported 4.1%, 6.9% and 11.3% versus 4.9% with placebo. In TRIUMPH-4, Lilly reported 12.2% and 18.2% versus 4.0%, and said this was highly correlated with starting BMI and included people who stopped for perceived excessive weight loss. In TRIUMPH-2, permanent discontinuation due to adverse events or death was 12% (9 mg) and 8% (12 mg) versus 4% (4 mg) and 5% (placebo). In TRANSCEND-T2D-1, it was 2 to 5% with retatrutide and 0% with placebo.
• Low blood sugar: no severe hypoglycaemia was reported in the phase 2 diabetes trial or in TRANSCEND-T2D-1.

Long-term safety has not been established in the sources checked. The longest trials ran for 80 weeks.

Products sold outside clinical trials carry extra risks. FDA Philippines says the public has no assurance of the quality, safety and efficacy of unregistered retatrutide products, and that using them may expose people to potential health risks, including possible injury or harm.

Development and approval status

Retatrutide is not approved for sale in any country in the sources checked. Lilly calls it investigational and says it is "legally available only to participants in Lilly's clinical trials."

On September 29, 2026, Lilly said it "plans to submit a Biologics License Application (BLA) in Q1 2027 to the U.S. Food and Drug Administration." A submission is a request for review, not an approval.

As of October 1, 2026, the US FDA says retatrutide is not a component of any drug it has approved, and that it "has not been found safe and effective for any condition".

Approval status with other regulators, such as those in Europe, the UK, Japan, Australia and Canada, was not checked on their own websites.

"Research purposes only" and unregistered retatrutide products

Some retatrutide products have been sold labelled "for research purposes" or "not for human consumption". As of October 1, 2026, the US FDA says it has warned companies that illegally sold unapproved retatrutide falsely labelled this way.

In the United States (US FDA):

• As of October 1, 2026, the US FDA says it has warned companies that illegally sold unapproved drugs containing retatrutide falsely labelled "for research purposes" or "not for human consumption". It urges consumers not to buy these products, "which are of unknown quality and may be harmful to their health."
• As of October 1, 2026, the US FDA also says retatrutide cannot be used in compounding under US federal law.

In the Philippines (FDA Philippines):

• FDA Advisory No.2026-1265, dated September 16, 2026: warned the public not to buy or use an unregistered retatrutide product. After post-marketing surveillance, FDA Philippines found it had no Certificate of Product Registration, so "the public has no assurance as to its quality, safety and efficacy". Establishments were warned not to distribute it.
• FDA Advisory No.2026-1392, dated September 22, 2026: warned the public not to buy or use a second unregistered retatrutide product, also without a Certificate of Product Registration. It warned that using it "may expose them to potential health risks, including possible injury or harm." Local government units and law enforcement agencies were asked to make sure it is not sold in their areas.

For how Philippine rules treat peptides in general, see are peptides legal in the Philippines.

How it compares with tirzepatide and semaglutide

Retatrutide has not been tested head to head against tirzepatide or semaglutide in the sources used for this page. The figures below come from separate trials with different people, durations and designs, so they cannot be compared directly.

Tirzepatide and semaglutide have their own pages: tirzepatide, semaglutide, and semaglutide vs tirzepatide.

Legal status in the Philippines

The Philippine registration status of retatrutide is unverified. No record was found in an FDA Philippines Verification Portal search on October 7, 2026. A search result is not an official FDA Philippines statement on the compound.

What is known:

• A search of the FDA Philippines website for "retatrutide" on October 7, 2026 returned only the two advisories on unregistered retatrutide products (2026-1265 and 2026-1392) and their Filipino versions.
• No source was found on whether retatrutide is classed as a prescription medicine in the Philippines.
• Lilly says retatrutide is legally available only to participants in its clinical trials. No source was found on whether any retatrutide trial has sites in the Philippines.

To check whether any product is registered, search the FDA Philippines verification portal at verification.fda.gov.ph.

FDA Philippines advisories

FDA Philippines has issued two advisories about unregistered retatrutide products. Each also has a Filipino version (2026-1265-A and 2026-1392-A).