Weight loss: the numbers

The weight loss gap between these two compounds is significant.

Metric	Wegovy (semaglutide 2.4mg)	Retatrutide (12mg)
Trial	STEP 1	Phase 2
Duration	68 weeks	48 weeks
Average weight loss	14.9%	24.2%
Max dose weight loss	14.9%	28.7% (at 48 weeks, still declining)
Participants losing 5%+	86.4%	~93%

Sources: STEP 1 (PMID: 33567185) and Retatrutide Phase 2 (PMID: 37385275)

A few important notes on these numbers.

The trials were not head-to-head. Different patient populations, different durations, different endpoints. Direct comparison has limits.

That said, the gap is hard to ignore. Retatrutide at the highest dose produced 28.7% body weight loss in 48 weeks, and the weight loss curve had not yet plateaued. Wegovy's 14.9% at 68 weeks is still a strong result. But retatrutide appears to be in a different category.

For more detail on retatrutide's trial data, see our retatrutide for weight loss breakdown.

Side effects comparison

Both compounds cause gastrointestinal side effects. Nausea, vomiting, diarrhea, and constipation are the most common with any GLP-1 based medication.

Side Effect	Wegovy	Retatrutide
Nausea	44%	25-43% (dose dependent)
Diarrhea	30%	22-35%
Vomiting	24%	9-18%
Constipation	24%	6-16%
Dysesthesia	Not reported	5-9%

Sources: STEP 1 (PMID: 33567185) and Retatrutide Phase 2 (PMID: 37385275)

Retatrutide's GI side effect rates vary significantly by dose. At lower doses, they trend below Wegovy's. At the highest dose (12mg), they are comparable.

The notable difference is dysesthesia. This is a tingling or numbness sensation that showed up in retatrutide's Phase 2 data. It was not reported with Wegovy. The clinical significance is still being studied in Phase 3 trials.

Wegovy has a longer safety record. It has been prescribed to millions of patients since 2021. Rare but serious risks include pancreatitis, gallbladder disease, and a boxed warning for medullary thyroid carcinoma (based on animal studies). We have years of post-market surveillance confirming its risk profile.

Retatrutide does not have that track record yet. Phase 2 data looks promising, but real-world safety data takes time.

The muscle loss question

One concern with all GLP-1 medications is muscle loss. When you lose a large amount of weight quickly, some of that weight comes from lean mass. Studies on semaglutide and muscle loss suggest that roughly 30-40% of weight lost may come from lean tissue.

Retatrutide's glucagon component is interesting here. Glucagon promotes fat oxidation specifically, which may theoretically help preserve lean mass during weight loss. Early data from the Phase 2 trial suggests a favorable body composition shift, but this has not been confirmed in larger studies.

This is an area to watch. If Phase 3 data confirms that retatrutide preserves more muscle than GLP-1-only drugs, that would be a meaningful clinical advantage.

Availability and cost

This is where the comparison gets simple.

Factor	Wegovy	Retatrutide
FDA status	Approved (2021)	Not approved
Expected availability	Now	Estimated 2027
Monthly cost	~$1,300	Unknown (expected similar range)
Insurance coverage	Expanding	N/A
Compounding	Limited	N/A

Wegovy is available right now with a prescription. Insurance coverage for weight management has expanded significantly since 2021, though gaps remain.

Retatrutide is not available through any legal channel. It is still in clinical trials. Anyone selling "retatrutide" online is selling a research chemical with no quality guarantees. We do not recommend sourcing unapproved compounds outside of clinical trials.

For a related comparison with another available option, see our retatrutide vs Ozempic breakdown.

Who is each better for?

Wegovy makes sense if you:

• Want a proven, FDA-approved option available today
• Have insurance coverage or can afford the monthly cost
• Need a medication with years of safety data behind it
• Are looking for 10-15% body weight loss

Retatrutide may be worth watching if you:

• Need more aggressive weight loss (20%+ body weight)
• Have not responded well to GLP-1-only medications
• Are interested in the potential muscle-preservation benefits of the glucagon component
• Can wait for FDA approval (likely 2027)

For most people right now, Wegovy (or another GLP-1 option) is the practical choice. It works, it is available, and we understand its risk profile.

Retatrutide represents the next generation. If the Phase 3 data holds up, it could become the new standard. But "could" is doing a lot of heavy lifting in that sentence.

Frequently asked questions

Is retatrutide better than Wegovy for weight loss?

In clinical trials, retatrutide produced nearly double the weight loss of Wegovy (28.7% vs 14.9%). However, these were separate trials with different populations. Retatrutide also has not completed Phase 3 trials or received FDA approval. The numbers are promising, but head-to-head data does not exist yet.

When will retatrutide be available?

Eli Lilly has Phase 3 trials underway. Based on typical FDA timelines, the earliest approval could come in 2027. This is an estimate. Regulatory timelines can shift based on trial results and FDA review priorities.

Can I switch from Wegovy to retatrutide?

Not currently. Retatrutide is not available outside of clinical trials. If and when it receives FDA approval, switching protocols will be established by prescribing guidelines. Your healthcare provider would manage any transition between medications.

Does retatrutide cause less muscle loss than Wegovy?

Early data suggests retatrutide's glucagon receptor activity may promote fat oxidation over lean tissue loss. This is a theoretical advantage that has not been confirmed in large-scale studies. Until Phase 3 body composition data is published, this remains an open question.

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This article was reviewed for accuracy by the Peptide Nerds editorial team. Last updated March 2026. We are not doctors. This content is educational, not prescriptive. Talk to your healthcare provider before making any decisions about medications.