Retatrutide vs tirzepatide October 2026

Quick answer

Only tirzepatide can be prescribed. FDA approved it as Mounjaro for type 2 diabetes on May 13, 2022 ^[9] and as Zepbound for chronic weight management on Nov 8, 2023 ^[8]. Retatrutide is in Phase 3 trials, and Lilly says no medicine containing it has been approved for human use by any regulator in the world ^[1]. Lilly plans to file for FDA approval in the first quarter of 2027 ^[4]. Until FDA approves it, the only legal way to take retatrutide is in a clinical trial.

Which is stronger is not settled. The two drugs have only been tested in separate trials. Lilly's TRIUMPH-5 trial (NCT06662383) compares retatrutide with tirzepatide in obesity ^[10], and we found no results announced as of Oct 25, 2026. More on each drug: retatrutide status and trials and our tirzepatide guide.

Side by side

Retatrutide vs tirzepatide, checked Oct 25, 2026

	Retatrutide	Tirzepatide (Zepbound, Mounjaro)
FDA status	Not approved by any regulator; investigational [1]	Approved: Mounjaro May 13, 2022 [9]; Zepbound Nov 8, 2023 [8]
What it is	Weekly injection that activates GIP, GLP-1 and glucagon receptors, which Lilly calls a triple hormone receptor agonist [3]	Weekly injection that activates GIP and GLP-1 receptors, a dual agonist [5]
Approved uses	None [1]	Zepbound: chronic weight management [8]; Mounjaro: type 2 diabetes [9]
Main obesity trial	TRIUMPH-1, 2,339 adults without diabetes, 80 weeks [3]	SURMOUNT-1, adults without diabetes, 72 weeks [6]
Average weight change, top dose vs placebo	-28.3% on 12 mg vs -2.2% (efficacy estimand); -25.0% vs -3.9% counting everyone who started [3]	-20.9% on 15 mg vs -3.1% [6]
Nausea	42.4% on 12 mg vs 14.8% on placebo [3]	25% to 29% across doses vs 8% on placebo [5]
Stopped for side effects	11.3% on 12 mg vs 4.9% [3]	4.8% to 6.7% vs 3.4% [5]
Boxed warning	No FDA label exists [1]	Thyroid C-cell tumors in rats [5]
Legal way to get it	Clinical trial only; FDA says it cannot be compounded [2]	Prescription for the brand; compounding only in narrow cases [12]
Self-pay price	No legal price [1] [2]	Zepbound $299 to $449 a month on LillyDirect [7]

How they work: triple vs dual agonist

Tirzepatide's label calls it "a GIP receptor and GLP-1 receptor agonist" ^[5]. GIP and GLP-1 are gut hormones released after eating, and the label says tirzepatide lowers calorie intake, likely by affecting appetite ^[5]. Retatrutide adds a third target. Lilly describes it as "an investigational, once-weekly, triple hormone receptor agonist" that acts on GIP, GLP-1 and glucagon receptors ^[3]. Glucagon is a hormone that acts on the liver and on energy use; whether the third target makes retatrutide safer or riskier in the long run is not known, because it has no approved label. For the drug class as a whole, see how GLP-1 medicines work.

Trial results

Lilly reports retatrutide results two ways. The efficacy estimand estimates the result if everyone had stayed on the drug; the treatment-regimen estimand counts everyone who started. In TRIUMPH-1, the 4, 9 and 12 mg groups lost an average of 19.0%, 25.9% and 28.3% of body weight at 80 weeks, against 2.2% on placebo, by the efficacy estimand ^[3]. Counting everyone, the figures were 17.6%, 23.7% and 25.0%, against 3.9% ^[3]. In TRIUMPH-2, in adults with type 2 diabetes, the 12 mg group averaged 20.8% vs 4.0% on placebo ^[4].

Tirzepatide's main weight trial, SURMOUNT-1, reported average losses of 15.0%, 19.5% and 20.9% on 5, 10 and 15 mg at 72 weeks, against 3.1% on placebo ^[6]. In adults with type 2 diabetes, Zepbound's label reports 12.8% on 10 mg and 14.7% on 15 mg vs 3.2% ^[5]. These are averages from trials, not a promise for any person. More on what people see in practice: Zepbound results.

1. Retatrutide 12 mg, 80 weeks28.3% ^[3]
2. Placebo, TRIUMPH-12.2% ^[3]
3. Tirzepatide 15 mg, 72 weeks20.9% ^[6]
4. Placebo, SURMOUNT-13.1% ^[6]

Retatrutide uses Lilly's efficacy estimand ^[3]; tirzepatide is from SURMOUNT-1 ^[6]. Different trials, so the bars do not compare directly.

Side effects in the trials

Both drugs mostly cause stomach and bowel side effects that rise with dose. In TRIUMPH-1, nausea affected 28.6%, 38.4% and 42.4% of people on 4, 9 and 12 mg, vs 14.8% on placebo, and vomiting reached 25.3% on 12 mg vs 4.8% ^[3]. Retatrutide also caused dysesthesia, abnormal skin sensations, in 12.5% on 12 mg vs 0.9% on placebo ^[3]. On Zepbound in its weight trials, nausea was 25% to 29% and vomiting 8% to 13% across doses, vs 8% and 2% on placebo ^[5].

More people stopped retatrutide for side effects at the top dose: 11.3% on 12 mg vs 4.9% on placebo ^[3], compared with 4.8% to 6.7% on Zepbound vs 3.4% on placebo ^[5]. Tirzepatide carries a boxed warning because it caused thyroid C-cell tumors in rats; people with a personal or family history of medullary thyroid carcinoma or MEN 2 should not take it ^[5]. Retatrutide has no label, so its warnings are not set. Full lists: tirzepatide side effects.

Price and how to get each one

Retatrutide has no legal price, because it is not approved and FDA says "retatrutide and cagrilintide cannot be used in compounding under federal law" ^[2]. Lilly has not announced a price. One market access analyst quoted by PharmaVoice estimated an approved list price of $1,000 to $1,500 a month; that is an estimate, not a Lilly figure ^[11].

Zepbound costs $299 for 2.5 mg, $399 for 5 mg and $449 for 7.5 to 15 mg a month through LillyDirect, checked Oct 25, 2026 ^[7]. The $449 price needs a refill within 45 days; otherwise it is $499 for 7.5 mg or $699 for 10 to 15 mg, and needles are extra ^[7]. Full tables: Zepbound cost and the cheapest tirzepatide options.

Compounded tirzepatide is a pharmacy-made version that is not FDA-approved, and FDA does not review it for safety, effectiveness or quality ^[2]. Since FDA declared the tirzepatide shortage over, a 503A pharmacy may compound it only for a specific patient, and copies are barred unless the prescriber documents a change that makes a significant difference for that patient ^[12]. Details: compounded tirzepatide.

Brand tirzepatide online (clean, provisional)

1. Ro (Ro Body Program)

   Clean

   Good fit for: brand drugs with prior authorization help

   PriceZepbound KwikPen $299 (2.5 mg), $399 (5 mg), $449 (7.5 to 15 mg) a month; Wegovy pill $149 to $299; Wegovy pen $199 for the first 2 months at 0.25 to 0.5 mg, then $349, or $399 for 7.2 mg. Membership $39 the first month, then $74 to $149 a month. Checked Oct 17, 2026 ^[13].

   What you get

   FDA-approved brand drugs only (Zepbound, Wegovy pen and pill, Foundayo, Ozempic). Helps with insurance prior authorizations.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   BBB profile not checked as of Oct 17, 2026.

   Note

   Membership is billed on top of the drug. The $74 rate needs a 12-month prepay. Verdict: clean (provisional). Ro review

   Visit Ro (Ro Body Program)on the Ro website

2. LifeMD

   Clean

   Good fit for: brand Wegovy or Zepbound with insurance help

   PriceZepbound vial from $299 a month, plus a program fee of $39 the first month and $149 a month after. Checked Oct 17, 2026 ^[14].

   What you get

   Brand GLP-1s, including Zepbound and Wegovy, with a benefits check for insurance coverage. Does not bill insurance for its program fee.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   BBB profile not checked as of Oct 17, 2026.

   Note

   People with Medicare or other government coverage are not eligible for its GLP-1 programs. Verdict: clean (provisional). LifeMD review

   Visit LifeMDon the LifeMD website

3. PlushCare weight loss

   Clean

   Good fit for: a prescriber plus prior authorization help

   PriceMembership $19.99 a month (first month free) plus $129 for the first visit without insurance; medication and labs extra. Checked Oct 17, 2026 ^[15].

   What you get

   Brand weight-loss prescriptions sent to your own pharmacy; no compounded drugs.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   BBB profile not checked as of Oct 17, 2026.

   Note

   Cheap visits, but you still pay the drug price at your pharmacy or through LillyDirect or NovoCare. Verdict: clean (provisional). PlushCare review

   Visit PlushCare weight losson the PlushCare weight loss website

Compounded tirzepatide (not FDA-approved; clean only)

1. bmiMD

   Clean

   Good fit for: low-price compounded GLP-1s

   PriceCompounded tirzepatide $249 a month on the 1-month plan, or $179 a month on the 12-month plan ($2,148 paid upfront). Same price at every dose. Checked Oct 19, 2026 ^[16].

   What you get

   Compounded semaglutide and tirzepatide, including microdose plans. Pharmacy not named.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   F; BBB cites 6 unanswered complaints out of 43, Oct 24, 2026 ^[17]

   Note

   Refund policy page could not be read. Trustpilot reviewers report warm deliveries and repeat charges. Verdict: clean (provisional). bmiMD review

   Visit bmiMDon the bmiMD website

2. Henry Meds

   Clean

   Good fit for: visits and medication in one price

   PriceGLP-1 program "starts at $179/mo" with visits, medication and supplies included; the page does not say which drug or dose. A $30 consult fee applies to each evaluation that ends in a prescription. Checked Oct 17, 2026 ^{[19] [20]}.

   What you get

   Compounded semaglutide and tirzepatide from 503A or 503B pharmacies it does not name, plus liraglutide and phentermine.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   F; BBB cites 31 unanswered complaints out of 236, mostly billing, cancellation and fulfillment, Oct 24, 2026 ^[21]

   Note

   Multi-month plans may bill the remaining balance if you cancel. Verdict: clean (provisional). Henry Meds review

   Visit Henry Medson the Henry Meds website

3. Found

   Clean

   Good fit for: compounded, brand and non-GLP-1 options

   PriceCompounded tirzepatide plan, medication included, per 28 days in cash: $359 (1-month plan), $309 (3-month), $289 (6-month), $239 (12-month). First month on the 1-month plan $219. Checked Oct 17, 2026 ^[18].

   What you get

   Compounded semaglutide and tirzepatide, brand GLP-1s, and non-GLP-1 drugs. Accepts insurance for visits.

   FDA record

   No FDA warning letter found as of Oct 17, 2026.

   BBB

   BBB profile not checked as of Oct 17, 2026.

   Note

   Billing every 28 days means 13 charges a year. Labs are extra. Membership is refundable only within 3 days or before the first consult. Verdict: clean (provisional). Found review

   Visit Foundon the Found website

Compare tirzepatide prices

Retatrutide sold online is not a legal option

Anything sold as retatrutide outside a trial is not Lilly's drug. FDA has warned telehealth companies, ingredient distributors and outsourcing facilities over retatrutide ^[2], and an Aug 24, 2026 warning letter to Peptide Partners cited "GLP-3 Reta" and rejected its "for research use only" label ^[22]. On Aug 12, 2026, Lilly announced six lawsuits against retatrutide sellers in federal courts in California and Texas and more than 200 referrals to FDA, the Justice Department, state attorneys general and licensing boards ^[1]. Lilly's statement: "What is being sold on the black market is not a medicine" ^[1]. We could not confirm the current status of each suit. More on these products: research-use-only GLP-1s.

Legal status of Retatrutide

Not approved: trials only

Retatrutide is an investigational drug that no regulator anywhere has approved ^[1]. FDA says it cannot be used in compounding ^[2].

FDA status

Lilly says no medicine containing retatrutide has been approved for human use by any regulator in the world ^[1]. FDA says retatrutide cannot be used in compounding under federal law ^[2]. FDA has warned sellers of "research purposes" GLP-1 products, including retatrutide ^[2].

Advisory committee

Not applicable. Retatrutide is an investigational drug, not a compounding substance ^[2].

FDA-approved products

None. No retatrutide medicine is approved ^[1].

Sports (WADA)

Retatrutide is not named on the 2026 list ^[23]. The list's S0 class covers substances with no approval by any government health authority for human use ^[23], and retatrutide has no approval anywhere ^[1]. Whether that class covers it is a judgment call, so athletes should ask their anti-doping agency before use.

What happens next

Lilly must file for approval and FDA must approve it. Lilly plans to submit a Biologics License Application to FDA in the first quarter of 2027 ^[4]. FDA review would follow, so a legal prescription is not possible before then.

Checked against FDA sources on Oct 19, 2026. We update this box when FDA acts. Report a change: [email protected].

Who each fits

• Tirzepatide fits adults who meet the Zepbound or Mounjaro label and want a treatment they can start now with a prescription ^{[5] [9]}. Coverage and price depend on the brand and diagnosis; see Mounjaro vs Zepbound.
• Retatrutide is only an option if you qualify for and join a Lilly trial, where you may get placebo or another drug ^[10]. How to search for one is on our retatrutide page. Other drugs still in testing are on the new weight loss drugs tracker.

Switching from tirzepatide to retatrutide

There is no legal switch today, and no label gives a switching plan, because retatrutide is not approved ^[1]. Any change after approval would depend on the final label and your prescriber. For moving between approved drugs, see switching GLP-1s and Wegovy vs Zepbound.

How we check

Retatrutide figures come from Lilly's own results releases, and we say which estimand each number uses. Tirzepatide figures come from the FDA label and the published SURMOUNT-1 trial. Prices come from LillyDirect and the providers' own pages on the dates shown. We do not link to retatrutide sellers. Our method: editorial standards.