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Mixing Tirz, Reta, Cagri in same vial?

8 replies8 peopleApr 28, 2026☆ Follow
Summary

Is it safe to mix tirzepatide, retatrutide, and cagrilintide together in one vial or syringe for a single injection?

Users currently stacking the three peptides report drawing them into one syringe for a single shot or injecting separately one after another. Several note that compatibility is uncertain and depends on the specific vial contents and reconstitution, with some peptides being harder to mix without issues like clouding. Pre-mixed products from certain sources have been recalled in the past, and one person mixes all three in a syringe while keeping doses low and staggered. Long-term stability and potential reactions remain untested by most participants.

What this discussion establishesWhere people disagree

Whether any mixing (even short-term in a syringe) is advisable versus keeping everything completely separate.

Still open

Whether the peptides remain stable or effective when combined for more than a few minutes, and what long-term effects mixing might have.

Nothing here is advice.

8 replies · 8 people
CopperBeacon94archiveopening postApr 28

I'm currently taking 1.5 mg of cagrilintide and 15 mg of tirzepatide. After increasing from 12 mg of tirzepatide by itself I dropped another 20 pounds or so but have stopped losing recently and am still well over my target of 240 pounds. Because of that I'm thinking about changing to retatrutide instead, yet doing three separate shots feels overwhelming and costly. Would it be okay to combine tirzepatide, retatrutide, and cagrilintide ahead of time in one vial and do one injection, or might they interact?

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AmberFenwick52archiveApr 28
↳ replying to @CopperBeacon94 (opening post)

I'm also wondering about that. What I do is pull the liquid from each vial into one syringe and give myself just the one shot.

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PlainAlder11archiveApr 28

Not sure about any reactions. I do recall seeing some videos about it on YT.

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CopperBeacon14archiveApr 28

I give these three as separate injections. Probably wouldn't want to combine them. Just do the shots one right after the other, it's fine.

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WryCinder57archiveApr 28
↳ replying to @CopperBeacon94 (opening post)

This might be useful for checking whether the peptides can be combined or not.

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SharpCinder28archiveApr 28

Even clear solutions in storage or injection equipment might hide complications when used over time. Take that medication by itself without any visible haze, it could still contain salt impurities that are harder to spot. The existence of a test for those impurities accounts for this, yet only a small number cover the expense.

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PatientHarbour23archiveApr 30

So I just started retatrutide last week and added cagrilintide last night. I did not mix them in one syringe or one vial, partly because I want to see if a specific pairing or stack works better than another. I took so little of retatrutide and cagrilintide last night that I'm sure I'll be eating a lot this weekend until my Saturday tirzepatide shot. And I'm debating whether I want to do cagrilintide with tirzepatide as well. Lots of testing.

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PatientHarbour23archiveMay 1
↳ replying to @PatientHarbour23

I believe the dizziness stems from adding that substance via the attachment, yet the day before I felt extremely dizzy from around eleven in the morning until three or later. The sensation eased up afterward even though I wasn't thirsty or in need of food, which made me concerned a balance-related headache was starting. I've experienced that just once over the previous five years following my stomach procedure. Since it resolved, perhaps that's what occurred. My pulse stayed steady throughout the period according to my tracker.

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CopperSignal27archiveMay 2

I've heard worries regarding cagri and its tendency to create fibrils, so I prefer keeping it isolated from other substances. When gradually transitioning over to reta, adjusting the amounts of tirz and reta becomes necessary, which gets complicated if everything is combined. Combining in a single syringe for multiple compounds reduces the number of shots and needles used, and it's less risky since the substances aren't together as long compared to pre-mixing in a container. Cagri works best on its own, yet for my current regimen I draw tirz at 4.5 mg with reta at 1.4 mg every two days along with cagri at 0.25 every four days all into the same syringe.

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