Have cagrilintide and retatrutide been studied together?

Only in rats: in a 2026 study, obese male rats given both daily for 16 days lost 22.6% of their weight, against 6.4% on cagrilintide and 13.6% on retatrutide alone. No study in people has tested the pair.

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Pair page — what's published on the two together

Cagrilintide with Retatrutide

Q: What is the legal status of Cagrilintide and Retatrutide?

Cagrilintide: Gray market. No FDA ruling — not on any list. Retatrutide: Gray market. No FDA ruling — not on any list.

Studied together once: a 2026 study in obese male rats, where the pair lowered weight more than either drug alone. No study in people.

Studied together: 1 rat study (2026)
Cagrilintide: Gray market · evidence: Controlled trials
Retatrutide: Gray market · evidence: Controlled trials

Studied Together

Obese male rats (Petersen et al., 2026)

What was given — Male rats made obese on a high-fat, high-sucrose diet were dosed daily for 13 to 16 days, in several experiments from one lab. In the head-to-head test, 10 rats per group got vehicle, cagrilintide, retatrutide or both (5 nmol/kg of each) for 16 days. Other groups set the pair against cagrilintide with semaglutide or with tirzepatide at the same doses, against rats pair-fed to the treated rats’ intake or calorie-restricted to the same weight loss, and across doses from 0.3 + 0.3 to 30 + 30 nmol/kg (the paper’s figures and published source data).
What it found — At day 16, weight changed −22.6% on the pair, −6.4% on cagrilintide and −13.6% on retatrutide, against +4.0% on vehicle (the pair vs each drug alone, P < 0.0001); rats on the pair also ate less (P = 0.0005 vs cagrilintide, P = 0.0001 vs retatrutide). At day 14 the pair (−17.6%) beat cagrilintide with semaglutide (−13.1%) or with tirzepatide (−10.6%), P < 0.0001 each. Rats fed the same amount as pair-treated rats lost less (−10.6% vs −18.1%, P < 0.0001), and weight loss grew with the dose, to −34.9% at 30 + 30 nmol/kg. The authors report improved cholesterol, triglycerides and insulin; in a taste-aversion test, each drug and the pair cut the rats’ preference for a flavour paired with the injection (P < 0.0001 vs vehicle).
Limits — One lab; male rats only; 13 to 16 days of dosing; not blinded, per the paper’s reporting summary. Funding included Novo Nordisk Foundation grants; three authors co-founded a company developing obesity drugs, and some report speaking or counselling fees or research support from Novo Nordisk, Eli Lilly or Zealand Pharma.

No study in people has tested cagrilintide with retatrutide, and ClinicalTrials.gov lists no trial of the pair (searched October 3, 2026).

Each Compound's Evidence

What each has shown on its own, from its Kalios card. The full profiles carry the sources.

Cagrilintide

Evidence: Controlled trials. The other half of Novo's CagriSema combo. Alone it's gray-market; paired, 20.4% weight loss at 68 weeks.

Retatrutide

Evidence: Controlled trials. Lilly's triple-hormone shot, trials only; gray-market copies sell anyway. Phase 2: 24.2% loss at 48 weeks.

Legal Status

Current Status — October 2026

Cagrilintide: Gray market. No FDA ruling — not on any list.

Retatrutide: Gray market. No FDA ruling — not on any list.

References

Petersen J, Merrild C, Holm SK, Kurgan N, Hassan S, Mathiesen CV, et al. Cagrilintide and retatrutide combination therapy enhances weight loss and metabolic outcomes in obese male rats. Nat Metab. 2026. PMID: 42744908.

Last updated: October 3, 2026 | A literature lookup, not a recommendation to combine anything.