Is retatrutide stronger than Wegovy?

The trial numbers point that way, but the drugs have never been tested head to head. Retatrutide 12 mg produced 28.3% average weight loss at 80 weeks in TRIUMPH-1. Semaglutide 2.4 mg produced 14.9% at 68 weeks in STEP 1. Different trials, different populations, and different lengths mean the gap is an estimate, not a measured difference.

Can I switch from semaglutide to retatrutide?

Not outside a clinical trial. Retatrutide has no FDA approval, and the FDA says it cannot legally be compounded. Products sold online as retatrutide are unverified. If semaglutide is not working for you, talk to your prescriber about approved alternatives such as tirzepatide.

Does retatrutide raise heart rate more than semaglutide?

The retatrutide Phase 2 trial reported a dose-dependent rise in heart rate that peaked around 24 weeks and then declined. Semaglutide also raises resting heart rate, and the Wegovy label lists it as a warning. Whether retatrutide's effect is larger will be clearer when the full Phase 3 papers are published.

Why does retatrutide use higher milligram doses than semaglutide?

Milligrams do not compare across different molecules. Retatrutide and semaglutide bind different receptors with different strengths, so each drug has its own dose range. Retatrutide was tested at 4 mg, 9 mg, and 12 mg weekly. Semaglutide for weight management uses 1.7 mg or 2.4 mg weekly, with higher doses added to the label in 2026.

When could retatrutide reach pharmacies?

Lilly says it plans to file its FDA application in the first quarter of 2027. Standard FDA review then takes months, so a decision before 2028 would be fast. No date is set, and approval is not guaranteed.

Retatrutide vs Semaglutide: How Do They Compare?

The short answer: Retatrutide activates three hormone receptors (GIP, GLP-1, and glucagon). Semaglutide activates one (GLP-1). In its Phase 3 TRIUMPH-1 trial, retatrutide 12 mg produced 28.3% average weight loss at 80 weeks. Semaglutide 2.4 mg produced 14.9% at 68 weeks in STEP 1. Semaglutide is FDA approved as Wegovy and Ozempic. Retatrutide is not approved anywhere, and Lilly plans to file with the FDA in early 2027.

How do the two drugs work differently?

Semaglutide is a GLP-1 receptor agonist. It mimics one gut hormone that slows stomach emptying, lowers appetite, and helps the pancreas release insulin after meals. Every effect of semaglutide, good or bad, comes from that single receptor.

Retatrutide is a triple agonist. The NEJM Phase 2 paper describes it as "an agonist of the glucose-dependent insulinotropic polypeptide, glucagon-like peptide 1, and glucagon receptors" (Jastreboff et al., NEJM 2023). The GLP-1 part works like semaglutide. The GIP part adds a second incretin signal. The glucagon part is the new piece. Glucagon receptor activation raises energy expenditure and pushes the liver to burn fat.

So the two drugs differ in kind, not only in strength. Semaglutide mainly reduces how much you eat. Retatrutide reduces intake and also raises how much energy the body uses.

How much weight do people lose on each?

No trial has compared the two drugs head to head. The best data come from each drug's own placebo-controlled trials. Populations and durations differ, so treat the gap as an estimate.

Semaglutide, STEP 1. The trial enrolled 1,961 adults with obesity or overweight and no diabetes. After 68 weeks, mean weight change was -14.9% with semaglutide 2.4 mg versus -2.4% with placebo. Weight loss of at least 5%, 10%, and 15% occurred in 86.4%, 69.1%, and 50.5% of semaglutide participants (Wilding et al., NEJM 2021).

Retatrutide, Phase 2. The 48-week trial enrolled 338 adults. Mean weight change was -24.2% at 12 mg versus -2.1% with placebo. At that dose, 83% of participants lost at least 15% of body weight (Jastreboff et al., NEJM 2023).

Retatrutide, Phase 3 TRIUMPH-1. This was the pivotal obesity trial, with 2,339 participants randomized. Lilly reported topline results on May 21, 2026. At 80 weeks, average weight loss was 19.0% at 4 mg, 25.9% at 9 mg, and 28.3% at 12 mg, versus 2.2% with placebo. Among people on 12 mg, 62.5% lost at least 25% of body weight and 45.3% lost at least 30%. A blinded extension in participants with a starting BMI of 35 or higher reached 30.3% at 104 weeks (Lilly, May 2026). ClinicalTrials.gov lists the study as completed on April 30, 2026 (NCT05929066).

Two more Phase 3 trials reported on July 23, 2026. In TRIUMPH-2, 1,152 adults with obesity and type 2 diabetes lost an average of 20.8% at 12 mg versus 4.0% on placebo, with A1C reductions of up to 1.6 points. In TRIUMPH-3, 1,949 adults with severe obesity and established cardiovascular disease lost 22.6% at 12 mg versus 3.2% on placebo (Lilly, July 2026).

Semaglutide's best trial result is about 15%. Retatrutide's is about 28%, or 30% with a longer run. That is roughly double, with the caution that cross-trial comparisons are rough. Our page on how much weight people lose on retatrutide breaks the results down by dose and trial.

How do the dosing schedules compare?

Both drugs are once-weekly subcutaneous injections. Both start low and step up to limit nausea. The milligram numbers are not comparable across the two molecules.

The Wegovy label, revised June 18, 2026, sets a 16-week escalation: 0.25 mg weekly for weeks 1 to 4, then 0.5 mg, 1 mg, and 1.7 mg for four weeks each. The maintenance dose from week 17 is 1.7 mg or 2.4 mg weekly. The 2026 label also allows a step up to 7.2 mg for additional weight reduction in adults (Wegovy label, DailyMed).

Retatrutide has no label, so there is no approved schedule. In TRIUMPH-1, participants started at 2 mg weekly and stepped up to a target of 4 mg, 9 mg, or 12 mg. Lower starting doses partly reduced stomach side effects in Phase 2.

How do the side effects compare?

The profiles overlap because both drugs share the GLP-1 mechanism. Nausea, diarrhea, vomiting, and constipation lead the list for both.

The Wegovy label reports these rates from its trials: nausea 44%, diarrhea 30%, vomiting 24%, constipation 24%, abdominal pain 20%, and headache 14%. Wegovy also carries a boxed warning about thyroid C-cell tumors seen in rodents. It is contraindicated in people with a personal or family history of medullary thyroid carcinoma or MEN 2. In STEP 1, 4.5% of semaglutide participants stopped because of gastrointestinal events, versus 0.8% on placebo.

In TRIUMPH-1, the retatrutide rates by dose (4 mg, 9 mg, 12 mg) were: nausea 28.6%, 38.4%, 42.4%; diarrhea 25.2%, 34.1%, 32.0%; vomiting 10.6%, 22.8%, 25.3%; constipation 23.8%, 25.9%, 26.1%. Placebo nausea was 14.8%. Discontinuation for adverse events was 4.1%, 6.9%, and 11.3% by dose, versus 4.9% on placebo. In TRIUMPH-3, 13.5% of the 12 mg group stopped for adverse events.

Two differences stand out. Retatrutide's dropout rate at the top dose is higher than semaglutide's in STEP 1. And the glucagon component adds a heart-rate question. The Phase 2 paper reported a dose-dependent rise in heart rate that peaked at 24 weeks and then declined. Our summary of retatrutide side effects tracks what each trial has reported.

Which one is approved?

Semaglutide is approved. Wegovy's label covers weight reduction in adults and children 12 and older, cardiovascular risk reduction in adults with heart disease, and noncirrhotic MASH with moderate to advanced fibrosis. Ozempic is the same molecule for type 2 diabetes. The ozempic.md site covers that product.

Retatrutide is not approved. As of September 3, 2026, no regulator anywhere has cleared it for human use. The FDA's page on unapproved GLP-1 drugs, updated September 1, 2026, states that retatrutide "cannot be used in compounding under federal law" and has "not been found safe and effective for any condition" (FDA, 2026). Lilly plans to submit a Biologics License Application in the first quarter of 2027. The company said it needs more time to gather manufacturing and quality-control data (BioPharma Dive, July 2026).

So the practical answer is simple. You can get semaglutide by prescription. You can get retatrutide only inside a clinical trial. Anything sold online as retatrutide is unverified.

Who might be a candidate for each?

Semaglutide fits anyone who meets the Wegovy label today: adults with obesity, adults with overweight plus a weight-related condition, and adolescents 12 and older with obesity. People with a history of medullary thyroid cancer or MEN 2 are excluded.

Retatrutide's place will depend on its label. The trials suggest three groups where it could matter most:

People who need very large weight loss. In TRIUMPH-1, 45.3% of the 12 mg group lost at least 30% of body weight. No approved drug has shown that.
People with type 2 diabetes and obesity. TRIUMPH-2 showed 20.8% weight loss and A1C reductions of up to 1.6 points in this group.
People with severe obesity and heart disease. TRIUMPH-3 enrolled this population and showed 22.6% weight loss at 12 mg.

The trade-off is tolerability. Higher retatrutide doses carried higher dropout rates. For someone who does well on semaglutide, a stronger drug may add side effects without adding benefit. For someone who plateaued with a lot of weight left to lose, retatrutide could be the next option once approved. For a comparison against the strongest approved drug, see our post on retatrutide versus tirzepatide.

The bottom line

Semaglutide hits one receptor and delivered about 15% weight loss in its pivotal trial. Retatrutide hits three and delivered about 28% at 80 weeks, at the cost of more dropouts at the top dose. Semaglutide is approved and available. Retatrutide will not reach the FDA until early 2027, and approval is not guaranteed. If you need treatment now, semaglutide or tirzepatide are the options that exist. If you can wait, the retatrutide data are the strongest any obesity drug has posted.

Last updated: September 2026. This article is for informational purposes only and does not constitute medical advice. Retatrutide is an investigational drug and is not approved for use outside of clinical trials. Talk to your prescriber before starting or changing any weight-loss medication.