GLP-1 and Amylin Stack: CagriSema, RetaCagri, CagriTirz and Other Pairings

What is the GLP-1 and amylin stack?

The GLP-1 and amylin stack pairs one weekly GLP-1-type weight-loss drug with one amylin drug, a copy of a fullness hormone made by the pancreas. Its best-known form is CagriSema (cagrilintide with semaglutide), the only pairing with phase 3 results; online, retatrutide with cagrilintide is more common, sold premixed as RetaCagri, and has never been tested in people. [1], [22], [38]

GLP-1-type drugs (semaglutide, tirzepatide, retatrutide) slow the stomach and quiet appetite; amylin drugs (cagrilintide, eloralintide, petrelintide) add a separate fullness signal. [1], [14] Besides CagriSema, filed for FDA approval in December 2025, only Lilly's eloralintide with tirzepatide has human data. [7], [15]

What's in it, and what else is it called?

The stack has two slots. The GLP-1 base is semaglutide, tirzepatide or retatrutide. The amylin partner is cagrilintide, eloralintide or petrelintide. Labels for semaglutide and tirzepatide say not to combine them with other GLP-1 medicines. [8], [9] No one has tested two amylin drugs together either, so the rule is one of each.

"CagriSema" names two different things. In trials it is Novo Nordisk's pen, which keeps each drug in its own chamber until the injection. Sellers use the same name for a premixed powder of the two drugs, which nobody has tested. [1], [36], [37]

What is in each blend in this stack?

Three premixed names appear on current seller pages: the CagriSema vial (cagrilintide with semaglutide), RetaCagri (retatrutide with cagrilintide) and CagriTirz (cagrilintide with tirzepatide). FDA named a fourth, CagriLean, in a 2024 warning letter. None of these vials has been tested in people. [29], [36], [38], [40]

Amounts below are what seller pages state. They are not doses, and not proof of contents.

CagriSema vial

Cagrilintide and semaglutide at 1:1, so 1 mg of powder holds 500 mcg of each.

• How it differs from the trial product: Novo Nordisk's CagriSema is a ready-made solution in a two-chamber pen, and its REDEFINE 1 result (20.4% weight loss) belongs to that product. Seller vials are one freeze-dried powder with both drugs mixed. [1]
• Stated amounts: a vendor page labeled "CagriSema" starts cagrilintide at 0.3 mg with semaglutide at 0.25 mg, unequal amounts a 1:1 vial cannot deliver (combination schedules). The page presents this as the trial schedule, but the trials started both drugs at 0.25 mg. [1], [46]
• Regulators: no notice we found names the "CagriSema" vial; FDA has warned online sellers of cagrilintide. [29], [30]

RetaCagri

Retatrutide with cagrilintide, the pairing most discussed online. Retatrutide is most of the powder, so the cagrilintide dose rises every time the retatrutide dose does.

• Where sellers disagree: on the ratio (4:1, 5:1 or not stated); community education groups describe others, so only the label decides. [38], [39], [42]
• "12.5 mg" labels: a "12.5 mg" RetaCagri can mean 10 + 2.5 mg in total (4:1) or 12.5 mg retatrutide + 2.5 mg cagrilintide (5:1); check each amount. [38], [45]
• What cagrilintide is claimed to add: hunger control late in the week. No human trial has tested it with retatrutide; the only data come from obese rats. [22]
• Stated amounts: on the 5:1 page, 6 mg of retatrutide brings 1.2 mg of cagrilintide, more than four times the usual 0.25 mg add-on start. [42]
• Regulators: no notice names RetaCagri; FDA says neither drug can be compounded. [28]

CagriTirz

Cagrilintide with tirzepatide at 1:1. One seller calls it CagriTirz; another sells the same pairing without a name.

• What cagrilintide is claimed to add: the same late-week fullness; the pairing has never been tested in people. At 1:1, the first 2.5 mg tirzepatide dose carries 10 times cagrilintide's usual start (worked example). [9], [1], [40]
• Regulators: no notice names CagriTirz; FDA has warned online sellers of "research" tirzepatide. [30]

CagriLean

FDA's December 2024 warning letter to an online seller lists "CagriLean (Cagrilintide and Semaglutide)" among unapproved new drugs. The letter gives no amounts, and we found no current seller page for the name. [29]

Other names you may see

"eloraTZP" is Lilly's trial name, not a product. "Hulk" is not a GLP-1 or amylin blend: the seller page cited here lists it as a tesamorelin and ipamorelin nasal spray, and other sellers use it for CJC-1295 with ipamorelin or BPC-157 with TB-500 (see the CJC-1295 and ipamorelin stack and the tesamorelin and ipamorelin stack). [46] We found no public premix of eloralintide or petrelintide, and no public source confirming what other nicknames contain. [15] Amino-acid injections sold alongside GLP-1 drugs are not peptide blends; see the GLP-1 support stack.

Why do people combine a GLP-1 and an amylin drug?

People add an amylin drug to get more weight loss, or steadier appetite control, without raising the GLP-1 dose. The idea has trial support only for CagriSema; for every other pairing it is a rationale, not proof. [1], [22]

• Two fullness signals. The drugs act on different receptors, so their effects may add up; REDEFINE 1 supports this for semaglutide with cagrilintide. [1]
• Hunger late in the week. In community education groups, the most common reason is appetite returning 4 to 6 days after the weekly GLP-1 injection, often on retatrutide.
• A plateau, or a lower GLP-1 dose. Some add cagrilintide instead of stepping up the GLP-1 drug, or to hold or lower it.
• One injection. A premix means one weekly shot instead of two.

Educators in those groups prefer this to adding a second GLP-1-type drug, which the labels advise against. [8], [9]

What does the evidence show?

Cagrilintide with semaglutide has been tested together in large trials. Eloralintide with tirzepatide has early human results. Every other pairing relies on separate trials of each drug.

Semaglutide

In STEP 1, average weight loss was 14.9% at 68 weeks on 2.4 mg, versus 2.4% on placebo. [10] Full semaglutide evidence

Tirzepatide

In SURMOUNT-1, adults without diabetes on 15 mg lost 20.9% at 72 weeks, versus 3.1% on placebo. [11] Full tirzepatide evidence

Retatrutide

In TRIUMPH-1, people without diabetes on 12 mg lost 28.3% at 80 weeks versus 2.2% on placebo, as reported by Lilly for people who stayed on treatment; the phase 2 trial is published. [13], [12] Full retatrutide evidence

Cagrilintide

Alone, cagrilintide 2.4 mg led to 11.5% weight loss at 68 weeks in REDEFINE 1, versus 3.0% on placebo. [1] Full cagrilintide evidence

Eloralintide

In a 48-week phase 2 trial, average weight change ranged from −9.5% on 1 mg to −20.1% on 9 mg, versus −0.4% on placebo, counting time on treatment. [14] Full eloralintide evidence

Petrelintide

In the phase 2 ZUPREME-1 trial, average weight loss at 42 weeks was 8.7–10.7% across five doses, versus 1.7% on placebo, as reported by the companies. [20] Full petrelintide evidence

The combinations

• Early CagriSema trials. Cagrilintide did not change semaglutide blood levels over 20 weeks. In type 2 diabetes, weight fell 15.6% at 32 weeks on CagriSema, 5.1% on semaglutide and 8.1% on cagrilintide. [2], [3]
• REDEFINE 1 (68 weeks). CagriSema 2.4 mg of each: −20.4%, versus −14.9% on semaglutide, −11.5% on cagrilintide and −3.0% on placebo. In REDEFINE 2, in type 2 diabetes, weight fell 13.7%. [1], [4]
• Against tirzepatide. In REDEFINE 4, an 84-week open-label trial, CagriSema led to 20.2% weight loss versus 23.6% on tirzepatide 15 mg and did not meet its goal of matching it. In REIMAGINE 5, CagriSema at 1.0 mg of each beat tirzepatide 5 mg in type 2 diabetes (−12.4% versus −9.1%). Both are company-reported. [5], [6]
• Eloralintide with tirzepatide. Lilly reports 17% weight loss at 16 weeks with eloralintide 3 mg plus tirzepatide 5 mg, versus 10% on tirzepatide alone. Lilly scheduled phase 2 results for presentation on September 30, 2026. [15], [16], [17]
• Not tested in people. Cagrilintide with retatrutide (obese rats only), cagrilintide with tirzepatide, any retatrutide and amylin pairing, and petrelintide with anything (rat and formulation studies only). [22], [23], [24]
• Planned or running. Eloralintide added to stable semaglutide or tirzepatide (phase 3 ENLIGHTEN-6, recruiting), petrelintide with Roche's enicepatide (not yet recruiting) and CagriSema's heart-outcomes trial. [18], [62], [21], [57]

How do the GLP-1 and amylin stack protocols line up?

These are each drug's own schedule. Only cagrilintide and semaglutide have been given together, in CagriSema's matched form below. [1]

Schedules published for the combination

Each row is a complete schedule from one source, with that source's amounts kept together.

The two retatrutide pages give very different retatrutide amounts for the same weeks, 12 mg versus 4 mg at maintenance. Neither has been tested. [44], [45]

Blend amounts

What one dose delivers at each vial's stated ratio. Arithmetic only, not a dose recommendation.

How people line them up

Add-on pages mostly keep the GLP-1 drug on its own ladder and add cagrilintide at 0.25–0.5 mg, some up to 1 mg; one copies the trial steps onto tirzepatide or retatrutide. [47], [48], [49], [50] Some inject both the same day, as with CagriSema; others wait 3 to 4 days to cover late-week hunger. No study has compared them, and with a half-life of about a week cagrilintide never clears between doses. [2], [44], [47] In community education groups, most start eloralintide at 1 mg, a phase 2 dose group but not a tested add-on dose. [14]

These schedules come from protocol sources; only CagriSema's was tested as a combination.

Plan it once. Two weekly ladders that step on different weeks, or a blend whose ratio moves both drugs, are easy to mix up.

What are the overlapping risks and interactions?

Both drug types slow the stomach and cut appetite, so their stomach side effects and the risk of eating and drinking too little add up. CagriSema's trials show what that looks like for one pairing; for the others there are no combination safety data. [1]

• Stomach and bowel effects. In REDEFINE 1, 79.6% of people on CagriSema had them, mostly while doses rose, versus 39.9% on placebo; by week 68 only 57.4% were on the full dose of each. [1]
• Eating and drinking too little. Vomiting or diarrhea that stops you keeping fluids down can harm the kidneys. [8], [9] In community education groups, fatigue and forgetting to eat are the usual complaints about cagrilintide add-ons.
• The base drug's warnings. Pancreatitis, gallbladder disease and a thyroid tumor warning from rodent studies; retatrutide also raised heart rate in its phase 2 trial. [8], [9], [12]
• Surgery and sedation. A slower stomach can hold food during anesthesia, so tell the care team about every weight-loss injection. [9]
• What is in the vial. FDA has warned online sellers of cagrilintide and tirzepatide, and we found no verifiable independent testing of any premix. [29], [30]

Interactions. Cagrilintide did not change semaglutide levels in the phase 1b trial. A study of CagriSema with atorvastatin and warfarin is registered without posted results. [2], [27] Semaglutide or tirzepatide with insulin or a sulfonylurea raises the risk of low blood sugar, and tirzepatide can make birth-control pills less reliable for 4 weeks after the first dose and after each dose step. [8], [9] The older amylin drug pramlintide carries label advice on timing oral medicines. [26]

Be especially cautious or avoid them in pregnancy, breastfeeding or when trying to conceive; under 18; with past pancreatitis, a personal or family history of medullary thyroid cancer or MEN 2; with an eating disorder or low body weight; before surgery; and in competitive sport. [8], [9]

Legal and sport status (checked September 26, 2026):

• United States: semaglutide and tirzepatide are FDA-approved. CagriSema was filed in December 2025, with a decision expected in late 2026. FDA says cagrilintide and retatrutide cannot be compounded. [8], [9], [7], [6], [28]
• Canada: semaglutide and tirzepatide are authorized; none of the other four is, based on a Drug Product Database search on September 26, 2026. Health Canada warned in April 2026 against injecting peptides bought online. [31], [59], [64], [32]
• Australia: cagrilintide is not on the Australian Register of Therapeutic Goods, and TGA says "research use only" labels do not change that. [33], [34]
• Sport: semaglutide and tirzepatide are monitored, not banned; the four unapproved drugs fall under WADA's ban on non-approved substances. [60], [35]

What should be monitored?

What the labels and trials of the parts measured:

• Weight, and whether you still eat enough protein and fluid. [1], [14]
• Stomach symptoms after either drug steps up, and pain that could mean pancreatitis or gallstones. [1], [8]
• Blood sugar and HbA1c, closely with insulin or sulfonylureas; kidney function after vomiting or diarrhea. [3], [8], [9]
• Heart rate with retatrutide. [12]
• Energy: in eloralintide's phase 2 trial, fatigue affected up to 46% of one dose group, versus 12% on placebo. [14]

What happens when you stop?

On average, people regain weight after a GLP-1 drug is stopped, and nobody has studied stopping one part of this stack while continuing the other. [54], [55]

• Semaglutide. In STEP 4, people switched to placebo regained 6.9% over 48 weeks; a year after STEP 1 ended, people had regained about two-thirds of their loss. [54], [56]
• Tirzepatide. In SURMOUNT-4, people switched to placebo regained 14.0% over 52 weeks. [55]
• Cagrilintide. Its phase 2 authors reported "some weight regain" six weeks after stopping; with a half-life of about a week, it fades over several weeks. No weight results after stopping CagriSema are published. [58], [2], [1]

Premixed blend or separate vials?

A premixed vial means one injection, but it locks the ratio, cannot follow two different ladders, and has no stability testing as a mixed powder. Separate vials take two injections but let each drug step up or down on its own.

• Mixing and stability. Novo Nordisk keeps CagriSema's drugs in separate chambers; its patents describe earlier versions that were "not stable during storage", and another company reports "major solubility, physical, and chemical compatibility issues" in one solution. A Novo study of combined versus separate injections has posted no results. The stability of a mixed seller vial is not established. [1], [51], [52], [53], [25]
• The ratio is locked. CagriTirz at 1:1 shows the problem: tirzepatide starts at 2.5 mg, so the first dose also delivers 2.5 mg of cagrilintide, 10 times the 0.25 mg trial start. Lowering the dose to ease nausea lowers both drugs. [40], [9], [1]
• Tracking and troubleshooting. With separate vials, a side effect after a step can be traced to the drug that changed; with a blend, both changed.
• Units. Blend doses are weights of the whole powder. "0.5 mg of CagriSema" is 0.25 mg of each drug. Work out syringe units for your own vial with the reconstitution calculator. [43]

Community education groups often advise buying the two drugs separately after first blend doses felt too strong.

Common questions about the GLP-1 and amylin stack

Is a CagriSema vial the same as Novo Nordisk's CagriSema?

No. Novo Nordisk's CagriSema is a two-chamber pen tested in trials and not yet approved. "CagriSema" vials sold online are premixed powders, usually 5 mg of each drug, that have never been tested in people. [1], [7], [37]

Can you take cagrilintide with retatrutide or tirzepatide?

It has not been tested in people. The only data on retatrutide with cagrilintide come from obese rats, and no trial has tested tirzepatide with cagrilintide. CagriSema's results belong to semaglutide with cagrilintide at matched doses. Lilly is testing its own amylin drug, eloralintide, with tirzepatide. [22], [1], [15]

What is RetaCagri?

A premixed vial of retatrutide and cagrilintide, 10 mg with 2.5 mg (4:1) at one seller. Neither drug is approved, and the pairing has not been tested in people. [38], [22]

Does CagriSema work better than tirzepatide?

Not at top doses. In REDEFINE 4, CagriSema led to 20.2% weight loss versus 23.6% on tirzepatide 15 mg. At lower doses in type 2 diabetes, CagriSema 1.0 mg of each beat tirzepatide 5 mg. Both results are company-reported. [5], [6]

Related guides

How this guide was researched

How this guide was made

This stack guide re-cites the original sources verified for the semaglutide, tirzepatide, retatrutide, cagrilintide, eloralintide and petrelintide guides. New research covered what the combination raises: trials of the drugs together, registered combination studies, blend names and seller-stated contents, stability of mixed formulations, and regulator notices. Community education groups informed how use is described; no private post is quoted or linked.

The research file holds 115 records, 106 verified against the original page; this guide cites 64. Seller pages are cited only for listed contents and their own claims, never as evidence of purity or effect. Drafting used AI assistance under Doserly's editorial rules, followed by source checks and editorial review. It is general education, not medical advice.

Explore the sources