Retatrutide Side Effects: What Lilly’s Phase 3 Toplines Report (Not a Complete Label)
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Disclosure. This page is informational, not medical advice. It does not diagnose, treat, dose, or recommend a therapy for any person. NextGenGLP1 is not Eli Lilly and Company. We may earn a commission if you use partner links, at no extra cost to you. Partner offers on this page are not retatrutide. Compounded medication is not FDA-approved. A prescription, if any, is issued only after a medical consultation. See Privacy and Terms.
Retatrutide is not FDA-approved. As of 26 August 2026 it is investigational. Lilly said on 23 July 2026 that it plans to submit a Biologics License Application (BLA) in Q1 2027. That is a filing target, not an approval, not a launch, and not a PDUFA date. None has been assigned.
This page is not a complete label. It quotes 12 mg adverse-event rates from Lilly Phase 3 press releases and, for TRANSCEND-T2D-1, from the Lancet paper. Only TRANSCEND-T2D-1 is peer-reviewed. Lilly has said TRIUMPH detailed results will be presented and published; toplines can move. It does not copy boxed warnings from Wegovy, Zepbound, or Foundayo onto retatrutide.
Status (as of 26 August 2026)
| Item | Status |
|---|---|
| FDA approval | Not approved for any use |
| Planned U.S. filing | BLA in Q1 2027 (Lilly, 23 July 2026; reconfirmed 5 August 2026). Filing is not approval. |
| PDUFA date | None. No application has been accepted. |
| Approval year | Not announced. This page does not assign 2027 or 2028. |
| Complete prescribing information | None. There is no FDA label to quote. |
| Peer-reviewed Phase 3 safety | TRANSCEND-T2D-1 only (Bajaj et al., The Lancet, 6 June 2026). TRIUMPH manuscripts promised; toplines can move. |
| Lilly consumer waitlist | None announced. This site’s email list is not a Lilly program. |
Regulatory calendar: Retatrutide FDA approval status 2026. There is no licensed product to price: expected cost. You cannot buy retatrutide as a licensed medicine: can you buy retatrutide?
How to read the 12 mg table
- Rates below are 12 mg unless a 9 mg figure is labeled.
- Where a second percentage appears, it is placebo from that same source. This page does not invent a placebo number, and it does not fill a missing cell with a dash that looks like data.
- Not in topline means the cited Lilly release or paper did not publish that cell. It does not mean the rate is 0%.
- Trials enrolled different populations (knee osteoarthritis; obesity without type 2 diabetes; obesity with type 2 diabetes; severe obesity with established cardiovascular disease; type 2 diabetes on diet and exercise). Do not pool them. Do not rank them against tirzepatide from this table.
- TRIUMPH-4’s −28.7% mean weight change at 68 weeks is an efficacy-estimand result in that trial. It is not an adverse-event rate. The Phase 2 −24.2% figure (Jastreboff et al., N Engl J Med 2023) is leftover Phase 2 efficacy, not Phase 3 safety.
12 mg adverse-event rates (Lilly PRs; TRANSCEND-T2D-1 in the Lancet)
| Event (12 mg) | TRIUMPH-4 | TRIUMPH-1 | TRIUMPH-2 | TRIUMPH-3 | TRANSCEND-T2D-1 |
|---|---|---|---|---|---|
| Nausea | 43.2% / 10.7% | 42.4% / 14.8% | 28.0% | 22.4% | 26.5% |
| Diarrhea | 33.1% / 13.4% | 32.0% / 13.5% | 33.6% | 24.4% | 22.8% |
| Constipation | 25.0% / 8.7% | 26.1% / 10.9% | 16.8% | 15.7% | not in topline |
| Vomiting | 20.9% / 0.0% | 25.3% / 4.8% | 15.7% | not in topline | 17.6% |
| Dysesthesia | 20.9% / 0.7% (9 mg: 8.8%) | 12.5% / 0.9% | 7.3% | 6.4% | 4.4% |
| Discontinued for an adverse event | 18.2% / 4.0% | 11.3% / 4.9% | 7.7% | 13.5% / 4.8% | 5.1% |
Where two percentages appear, they are 12 mg / placebo from that source. “Not in topline” is not a hidden zero.
Gastrointestinal events in the published toplines
Across these 12 mg readouts, nausea, diarrhea, constipation, and vomiting were among the most commonly listed adverse events. The published 12 mg nausea rates are 43.2% (TRIUMPH-4), 42.4% (TRIUMPH-1), 28.0% (TRIUMPH-2), 22.4% (TRIUMPH-3), and 26.5% (TRANSCEND-T2D-1) — trial-specific figures, not a 40–50% band, and not a pooled incidence.
This page does not tell anyone what they will feel, what to eat, or how to change a dose. Those are clinical decisions. They are not in these toplines as a home protocol.
Dysesthesia is not a ~2% leftover
Older copy on this URL treated dysesthesia as rare at about 2%. That is not what the Phase 3 12 mg toplines report. In TRIUMPH-4, dysesthesia occurred in 20.9% on 12 mg versus 0.7% on placebo; Lilly also reported 8.8% at 9 mg. Later 12 mg figures were 12.5% versus 0.9% (TRIUMPH-1), 7.3% (TRIUMPH-2), 6.4% (TRIUMPH-3), and 4.4% (TRANSCEND-T2D-1).
Lilly’s TRIUMPH-4 release described those events as generally mild and rarely leading to discontinuation. That is Lilly’s wording from a topline, not a complete characterization, not a diagnosis, and not a prediction for any person.
Discontinuation attributed to adverse events
At 12 mg, Lilly reported adverse-event discontinuation of 18.2% versus 4.0% placebo in TRIUMPH-4, 11.3% versus 4.9% in TRIUMPH-1, 7.7% in TRIUMPH-2, 13.5% versus 4.8% in TRIUMPH-3, and 5.1% in TRANSCEND-T2D-1. In TRIUMPH-4, Lilly stated that those rates were highly correlated with baseline BMI and included discontinuations for perceived excessive weight loss. That is context from the 11 December 2025 release, not a reason to start or stop anything.
TRIUMPH-3 MACE: confidence intervals include 1.0
TRIUMPH-3 enrolled adults with severe obesity and established cardiovascular disease. It is not a dedicated cardiovascular outcomes trial. Lilly reported pre-specified analyses for time to first MACE:
- MACE-5 (all-cause death, heart attack, stroke, heart-failure event, or coronary revascularization): HR 0.82 (95% CI 0.55–1.22)
- MACE-3 (cardiovascular death, heart attack, or stroke): HR 1.12 (95% CI 0.64–1.96)
Both intervals include 1.0. That is not evidence that retatrutide lowers heart risk, and it is not evidence that it raises heart risk. This page does not spin either point estimate.
What a complete label would cover — and what this page does not
An FDA-approved prescribing information document, if one exists later, would be the place for boxed warnings (if FDA assigns any), contraindications, warnings and precautions, drug interactions, use in specific populations, the full adverse-reaction tables, and postmarketing language. Retatrutide does not have that document.
This page does not paste Wegovy, Zepbound, or Foundayo boxed warnings onto an investigational molecule. Foundayo (orforglipron) was FDA-approved on 1 April 2026; that is educational status only and is not a partner offer here. Comparison of retatrutide with tirzepatide as different drugs belongs on retatrutide vs tirzepatide — not as a claim that these adverse-event rates are interchangeable.
An unapproved product is not trial safety
Rates above come from randomized protocols with identified investigational product. A vial, Telegram listing, or compounded “triple” sold as retatrutide is not that product. Quality, identity, sterility, and dose are unknown. The FDA (31 March 2025) stated that compounding prescription drug products with retatrutide is not within the 503A or 503B exemptions. Lilly (12 August 2026) said no medicine containing retatrutide has been approved for human use by any regulator and that it cannot be sold to consumers. See Can you buy retatrutide?
This site’s waitlist vs TrimRX and Medvi
The NextGenGLP1 waitlist is an email list run by this site. It is for regulatory-milestone notes (for example, if Lilly files a BLA, or if FDA takes a public action). It is not an Eli Lilly waitlist and does not reserve a prescription.
Care that exists today is a different product. Investigational retatrutide adverse-event rates are not a reason to start it.
Primary partner — TrimRX (compounded GLP-1 + GIP; not retatrutide)
TrimRX is listed here as a telehealth path to compounded GLP-1 + GIP. That is not Zepbound, not Mounjaro, and not retatrutide. Compounded medication is not FDA-approved. A medical consultation is required; a prescription is not guaranteed. Pricing is on TrimRX — this page does not hardcode a monthly cash price. Retatrutide trial rates on this page are not a reason to start TrimRX’s product.
Secondary partner — Medvi
Medvi offers semaglutide and tirzepatide with licensed physicians, including a medical consultation. This page does not call Medvi compounded. It is not retatrutide. Eligibility and product selection, if any, are between the patient and the clinician. Investigational AE rates are not a reason to start Medvi’s products.
Email, not a queue
If you want a note when Lilly files or when FDA acts — not a drug, not a hold — join the NextGenGLP1 email waitlist.
Sources
- Lilly TRIUMPH-4 topline, 11 December 2025
- Lilly TRIUMPH-1 topline, 21 May 2026
- Bajaj et al., TRANSCEND-T2D-1, The Lancet, 6 June 2026 (doi:10.1016/S0140-6736(26)00967-0)
- Lilly TRIUMPH-2 / TRIUMPH-3 topline and Q1 2027 BLA plan, 23 July 2026
- Lilly Q2 2026 earnings, 5 August 2026 (BLA plan reconfirmed)
- Lilly, 12 August 2026 (unapproved retatrutide market)
- FDA letter on compounded retatrutide / 503A–503B, 31 March 2025
- Jastreboff et al., Phase 2, N Engl J Med 2023 (−24.2% at 48 weeks; not a Phase 3 adverse-event result)
Frequently Asked Questions
What side effects have been reported for retatrutide in Phase 3?
Lilly’s 12 mg toplines report gastrointestinal events (nausea, diarrhea, constipation, vomiting) and dysesthesia, plus adverse-event discontinuation rates that differ by trial. Those rates are quoted in the table on this page. This is not a complete list and is not a label.
Is this page a complete retatrutide safety label?
No. Retatrutide has no FDA-approved prescribing information. Only TRANSCEND-T2D-1 is peer-reviewed as of 26 August 2026. Lilly has said TRIUMPH manuscripts will follow. Toplines can move when full datasets are published.
Is retatrutide FDA-approved?
No. As of 26 August 2026, retatrutide is not FDA-approved for any use. Lilly (23 July 2026) plans to submit a Biologics License Application in Q1 2027. That is a filing target, not an approval, not a launch date, and not a PDUFA date. None has been assigned. See FDA approval status.
How common was dysesthesia in Phase 3?
It is not a ~2% finding. At 12 mg, Lilly reported dysesthesia in 20.9% versus 0.7% placebo in TRIUMPH-4 (9 mg: 8.8%), 12.5% versus 0.9% in TRIUMPH-1, 7.3% in TRIUMPH-2, 6.4% in TRIUMPH-3, and 4.4% in TRANSCEND-T2D-1. Those are trial-specific topline rates, not a pooled incidence and not a diagnosis.
Did TRIUMPH-3 show that retatrutide reduces — or increases — heart attacks?
Neither. TRIUMPH-3 is not a dedicated cardiovascular outcomes trial. Pre-specified MACE-5 HR was 0.82 (95% CI 0.55–1.22) and MACE-3 HR was 1.12 (95% CI 0.64–1.96). Both confidence intervals include 1.0. That is not proof of benefit and not proof of harm.
When will retatrutide be approved?
Unknown. Q1 2027 is Lilly’s stated BLA filing target, not an approval year. This page does not assign a 2027 or 2028 approval date. No PDUFA date exists until FDA accepts an application.
Are these trial rates a reason to start a compounded GLP-1 or dual agonist?
No. Investigational retatrutide adverse-event rates are not a reason to start a different product. Partner offers on this page are not retatrutide. TrimRX is compounded GLP-1 + GIP — not Zepbound, not Mounjaro, and not retatrutide; compounded medication is not FDA-approved. Medvi offers semaglutide and tirzepatide with licensed physicians. Care today is a different product.
Is the NextGenGLP1 waitlist a Lilly waitlist?
No. The waitlist on this site is an email list run by NextGenGLP1. It is not an Eli Lilly waitlist, not a prescription reservation, and not a pharmacy slot. Lilly has not announced a consumer waitlist.
Bottom line: As of 26 August 2026, retatrutide is not FDA-approved. Q1 2027 is Lilly’s BLA filing target, not an approval year. The 12 mg rates above are toplines (and one Lancet paper), not a complete label. Toplines can move.