Retatrutide + Cagrilintide
The tested version of this pairing uses a different GLP-1 and a very different ratio.
CagriSema paired cagrilintide with semaglutide, and it is the only stack on this site ever tested against each of its own parts. This blend swaps in retatrutide, the stronger compound, and shifts the balance heavily toward it. Nobody has tested the result.
Take the tested combination and upgrade half of it.
Cagrilintide has one serious body of evidence behind it, and all of it comes from being paired with semaglutide. That pairing is CagriSema, and it produced 22.7 percent average weight loss against 16.1 percent for semaglutide alone in the same trial.
Retatrutide beats semaglutide by a wide margin on its own, reaching 28.3 percent over 80 weeks. So the reasoning is straightforward: keep the amylin compound, swap the weaker GLP-1 for the stronger one, and expect more.
It is a reasonable thought, and two things complicate it. The ratio is not the same as the tested version, and retatrutide is not a bigger semaglutide.
Three benefits, and how well each one holds up.
The middle row belongs to retatrutide taken on its own. The bottom row belongs to CagriSema, which used semaglutide. Neither belongs to this blend.
Three questions, answered before anything else.
The tested version is roughly even. This one is not.
Where vendors publish amounts, this blend is 12.5 mg of retatrutide to 2.5 mg of cagrilintide.[4] CagriSema, the version with the trial behind it, used the two compounds at roughly equal amounts.
Roughly equal amounts of each. 3,417 patients over 68 weeks, with four arms so the combination could be measured against each compound on its own.[1]
Result: 22.7 percent average weight loss, against 16.1 for semaglutide alone and 11.8 for cagrilintide alone.
12.5 mg to 2.5 mg, where the amounts are published at all. Cagrilintide is a minority component by a wide margin.[4]
No trial exists for this pairing, at this ratio, or with this GLP-1.
That is a large change to make to a formula whose evidence is the reason for buying it. Anyone citing the CagriSema result as support for this blend is citing a trial that used a different drug in a different proportion.
The ratio may well be deliberate. Retatrutide is the stronger compound and a maker might reasonably want it to dominate. Nobody has published a rationale, so the reasoning is not available to check.
Stacking these two already fell short of adding up.
CagriSema is the one place anyone measured whether combining two weight loss compounds delivers what the parts promise, because the trial ran four arms.
Adjusted against placebo, semaglutide contributed 13.8 points and cagrilintide 9.5. Added together that predicts 23.3. The combination delivered 20.4, which is 88 percent of additive.[1]
That is the only hard number anyone has on whether stacking works, and it came from the most favourable case available: two compounds on separate pathways, tested properly. The CagriSema page covers it in full.
Retatrutide already covers three receptor systems including glucagon. Adding an amylin compound to it overlaps more with what the first compound is already doing than adding one to semaglutide did. That argues for less than 88 percent here rather than more, and nobody has measured it either way.
Six times, for the same product name.
We track four in-stock listings of this blend. The cheapest and the dearest differ by more than six times.[4]
The middle column is the useful one. Two vendors sell what they describe as the same thing, a 15 mg vial split 12.5 to 2.5, at a 48 percent price difference.
Half of the listings publish no composition at all, so for those there is no way to tell how much of either compound you are buying. The cheapest listing is one of them.
Buying the two compounds separately costs $67.48 and lets you set the balance yourself. On a blend whose ratio differs this much from the tested version, that is the stronger argument.
Both compounds hit the stomach, and one raises heart rate.
In TRIUMPH-1 at the top dose, against a placebo group: nausea in 42.4 percent against 14.8, diarrhoea 32.0 against 13.5, constipation 26.1 against 10.9, vomiting 25.3 against 4.8. About 11.3 percent stopped because of side effects, against 4.9 on placebo.[3]
Heart rate rose by around 6.7 beats per minute at the top dose. That is higher than tirzepatide or semaglutide produce, and it traces to the glucagon receptor retatrutide adds.[3]
In the CagriSema trial, gastrointestinal side effects reached 79.6 percent against 39.9 percent on placebo.[1] Amylin compounds slow stomach emptying, which is part of how they work and part of why they make people feel sick.
Nobody has measured what the two together do to either figure. The retatrutide pages cover the full side effect picture, including how differently people buying online report their experience.
Neither compound is approved anywhere.
Retatrutide has five positive Phase 3 trials and no approval from any regulator. Lilly plans to file in the United States in the first quarter of 2027.[2]
Cagrilintide is not approved either. Its application, as part of CagriSema with semaglutide, was filed in December 2025 with a decision expected in late 2026.[1]
So this blend combines two unapproved compounds in a proportion nobody has studied. Everything sold online is research chemical material, and that holds for both halves.
What people ask about this stack
Is this better than CagriSema?
Nobody has tested it, so there is no comparison to make. Retatrutide beats semaglutide on its own, reaching 28.3 percent average weight loss against 20.7. That is a reason to expect more from this pairing and not evidence that it delivers more. The blend also uses a very different ratio from the trial version.
How different is the ratio?
Substantially. CagriSema used the two compounds at roughly equal amounts. Where this blend publishes its composition, it is 12.5 mg of retatrutide to 2.5 mg of cagrilintide, so cagrilintide is about 17 percent by weight. Anyone citing the CagriSema result as support for this product is citing a trial that used a different drug in a different proportion.
Does stacking these add up?
In the one case anyone measured, it fell short. CagriSema delivered 88 percent of what simple addition of its two compounds would predict, and that was the most favourable case available. Retatrutide already covers three receptor systems, so adding an amylin compound overlaps more with what it is already doing than adding one to semaglutide did. That argues for less than 88 percent here, and nobody has measured it.
Why is the price range so wide?
We track four in-stock listings running from $32.48 to $170.00, more than six times. Half publish no composition at all, including the cheapest. The two that do publish are identical 15 mg vials at 12.5 to 2.5, priced $105 and $135. Buying the compounds separately costs $67.48 and tells you exactly what you have.
What does cagrilintide add?
A second route to feeling full. It copies amylin, a pancreatic hormone that slows how fast the stomach empties, which is a different path from the gut hormones retatrutide works on. In the CagriSema trial cagrilintide alone produced 11.8 percent weight loss. What it adds on top of retatrutide specifically has never been measured.
What are the side effects?
The stomach and gut, from both halves. In retatrutide's trials at the top dose, nausea hit 42.4 percent against 14.8 on placebo, with about 11.3 percent stopping because of side effects. In the CagriSema trial gastrointestinal effects reached 79.6 percent against 39.9. Retatrutide also raises heart rate by around 6.7 beats per minute, more than tirzepatide or semaglutide do. Compare against the other stacks.
What this page is built on
- 01REDEFINE 1, CagriSema against semaglutide, cagrilintide and placebo. 3,417 patients, 68 weeks, four arms. 22.7 percent weight loss against 16.1 for semaglutide alone and 11.8 for cagrilintide alone; placebo-adjusted contributions of 13.8 and 9.5 points against a combined 20.4. Gastrointestinal adverse events 79.6 percent against 39.9 on placebo. Application filed December 2025. PMID 40544433.
- 02Retatrutide Phase 3 programme. TRIUMPH-1 NCT05929066, 2,339 adults over 80 weeks, 28.3 percent at the top dose. US filing planned for the first quarter of 2027.
- 03TRIUMPH-1 adverse event figures against placebo, and the roughly 6.7 bpm heart rate rise at the top dose.
- 04Peptide Decoding vendor pricing data, 16 September 2026. Four in-stock blend listings from $32.48 to $170.00. Composition published on two of the four, both 15 mg at 12.5 mg retatrutide to 2.5 mg cagrilintide, priced $105.00 and $135.00. Lowest in-stock single-compound listings: retatrutide $32.48, cagrilintide $35.00.