Retatrutide vs Zepbound vs Mounjaro vs Wegovy

Educational only, not medical advice, and not a recommendation for any treatment. Talk to a licensed clinician.

Quick comparison

Read this before comparing numbers. Results come from separate trials with different people and designs, so they can't be compared directly. These trials enrolled different people over different lengths of time and report different estimands. They were not run head-to-head, so the percentages are not directly comparable. No head-to-head trial of retatrutide against tirzepatide or semaglutide has reported results.

How they work

• GLP-1 (all four): slows stomach emptying, increases fullness, and supports insulin release when glucose is high.
• GIP (tirzepatide, retatrutide): a second incretin hormone that adds to the GLP-1 effect.
• Glucagon (retatrutide only): researchers think it raises energy expenditure and affects liver fat. This is what makes retatrutide a "triple agonist" (Lilly).

Zepbound vs Mounjaro: same drug, different labels

Both contain tirzepatide. Mounjaro is FDA-approved for type 2 diabetes and Zepbound for chronic weight management (and OSA with obesity). Insurance coverage and price can differ between them. See the GLP-1 cost guide. Seeing these sold online? Read how to tell what's real.

Side effects in common

In all four, the most common side effects reported in trials are gastrointestinal (nausea, diarrhea, vomiting, constipation). Approved labels carry a boxed warning about thyroid C-cell tumors. Read the official prescribing information for each drug. Retatrutide trials also reported dysesthesia more often than placebo (Lilly).

Pricing

• Zepbound, Mounjaro and Wegovy: see current manufacturer self-pay prices in the cost guide.
• Retatrutide: no price has been announced. Any figure is projected. One reasonable assumption is that launch pricing would sit near Lilly's existing branded obesity drugs, but Lilly has said nothing about it.

Also approved: oral options

• Foundayo (orforglipron), Lilly's daily oral GLP-1 pill for weight management (Lilly).
• Wegovy pill (oral semaglutide), sold through NovoCare.

Follow the retatrutide approval tracker. Updated whenever a label, trial result, or price changes.

Check these 4 things before you sign up

What should I check before using an online GLP-1 program?

Check four things: the program requires a screening and a prescription from a licensed clinician; it fills the prescription at a state-licensed pharmacy; it tells you whether the drug is an FDA-approved brand-name product or a compounded one, since compounded versions are not FDA-approved; and a licensed clinician is available to answer questions after you start. The FDA warns against sellers that skip the prescription, claim a compounded drug is the same as an approved one, offer prices that seem too good to be true, or sell products labeled "for research purposes" or "not for human consumption."

Sources: FDA; FDA BeSafeRx. Last checked Nov 2, 2026.

Questions