Retatrutide for Weight Loss: Trial Results, FDA Status and What to Use Now
Retatrutide (“reta”) produced about 24% weight loss in a Phase 2 trial, the highest result of any weight loss drug to date. This guide covers how retatrutide works, how it compares with tirzepatide and semaglutide, and whether you can get it yet.
Clinically checked Checked · Author: Top Weight Loss Research Team · Our review process
Can you get retatrutide today?
No. Retatrutide is not FDA-approved yet, so no one can legitimately prescribe or sell it for weight loss. It is in late-stage trials, and approval may come in 2026-2027. Below you will find how the drug works, how it measures up against approved options, and which approved treatments you can start now.
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Retatrutide is a once-weekly investigational injection developed by Eli Lilly. It is a triple agonist, meaning it switches on three receptors together: GLP-1 and GIP, the same pair tirzepatide targets, plus glucagon. The glucagon action is thought to raise metabolism and fat burning in addition to reducing appetite. That combination is the likely reason retatrutide has shown the biggest weight loss of any drug tested so far.
How does retatrutide compare with tirzepatide and semaglutide?
The highest retatrutide dose led to a loss of about 24% of body weight over 48 weeks in a Phase 2 study published in 2023. That beats the figures tirzepatide (~20%) and semaglutide (~15%) reached in their own trials. Phase 3 trials are now in progressto confirm the result and check long-term safety. The early data look strong, but only the Phase 3 results and the FDA’s review will decide if and when patients can use it.
What should you take while you wait for retatrutide?
The strongest approved alternatives are tirzepatide (~20% weight loss in trials) and semaglutide (~15%). Licensed telehealth providers prescribe both online, frequently as lower-cost compounded versions. Weigh providers on price, medical support and overall value before you choose.
Retatrutide is an investigational weight loss injection from Eli Lilly that is taken once a week. It is often shortened to “reta” or described as a “triple agonist” because it acts on three receptors: GLP-1, GIP and glucagon. Semaglutide acts on GLP-1 only and tirzepatide acts on GLP-1 and GIP, and retatrutide has produced the largest trial weight loss of any drug so far.
How much weight can you lose on retatrutide?
In a Phase 2 trial, people on the highest retatrutide dose lost about 24% of their body weight in 48 weeks. That is more than tirzepatide (~20%) or semaglutide (~15%) achieved in their own trials. These are early figures, and larger Phase 3 trials are underway to confirm them.
Is retatrutide FDA-approved?
No. As of 2026, retatrutide is still investigational and the FDA has not approved it for weight loss or any other use. Eli Lilly is testing it in late-stage Phase 3 clinical trials.
When will retatrutide be available?
Retatrutide's availability depends on its Phase 3 results and on FDA review. Industry expectations put a possible approval somewhere in 2026-2027, although that timeline could move. Until the FDA approves it, retatrutide cannot be legitimately prescribed for weight loss.
Is retatrutide more effective than tirzepatide?
In trials, retatrutide produced more weight loss (~24%) than tirzepatide (~20%+). The difference is that tirzepatide is FDA-approved and can be prescribed now, while retatrutide is still investigational. For anyone starting treatment today, the real choice is between approved drugs, with retatrutide a possible option later.
Can I buy retatrutide online?
No. Retatrutide is not FDA-approved, so it cannot be legitimately bought or prescribed for weight loss. Treat any website offering “retatrutide” with caution, because an unapproved drug from an unknown source carries real safety and legal risks. Use an approved medication prescribed by a licensed clinician instead.
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Sources: retatrutide Phase 2 trial results (New England Journal of Medicine, 2023) and the manufacturer’s trial program details; published tirzepatide (SURMOUNT) and semaglutide (STEP) trial data. All trial figures are averages, and individual results differ. Drug and brand names belong to their respective manufacturers.
topweightloss.us does not provide medical care or prescribe medication. This page is educational and is not medical advice. Retatrutide is an investigational drug without FDA approval. Talk to a licensed healthcare provider about the approved treatments that suit you.
