CommunityDosing & Titration

Those combining Reta and Tirz

27 replies14 peopleJul 22, 2026☆ Follow
Summary

How do people combine retatrutide and tirzepatide without exceeding safe total GLP exposure, and what results or dosing strategies do they report?

Participants describe running combinations such as 15 mg tirzepatide plus 6 mg retatrutide or 10 mg of each for extended periods, mainly when standard maximum doses have not produced sufficient weight loss in severe obesity. Several note that GLP-1 receptor saturation means extra tirzepatide may add little once retatrutide is present, shifting any benefit to GIP or glucagon activity. Opinions differ on whether retatrutide’s glucagon effect begins at a specific dose like 4 mg, and some users report no added benefit from stacking while others continue for stubborn fat. Risks are acknowledged but often viewed as acceptable compared with untreated obesity.

What this discussion establishesWhere people disagree

Whether retatrutide’s glucagon component activates only above 4 mg and whether stacking produces meaningful extra benefit versus single agents.

Still open

Long-term safety and optimal titration schedules for combined high-dose use.

Nothing here is advice.

27 replies · 14 people
SteadyAnchor13archiveopening postJul 22

For anyone stacking retatrutide with tirzepatide, how do you keep the overall GLP load from getting too high once doses rise? I figure the combined total should stay below 15 mg because that is the tirzepatide ceiling, but maybe retatrutide contributes less GLP activity per milligram. Has anyone run something like 12 mg retatrutide plus 6-8 mg tirzepatide for several months straight?

BrightCompass57archiveJul 22

Plenty of people here are on high doses if you look around, but why are you interested in trying this? Has your weight loss stopped progressing?

LevelThistle44archiveJul 22
↳ replying to @SteadyAnchor13 (opening post)

You are overthinking it when there is not enough data to draw firm lines about a 15 mg total cap. Go by results and how you feel. I am on 18 mg reta and 0.25 mg sema each week and it is going well. I came from tirz, had some overlap, and took my last 2.5 mg tirz dose on 3/12/26 while already at 10-11 mg reta.

CopperSignal27archiveJul 22

I have been on 15 mg tirz and 6 mg reta for about a year and recently added 0.5 mg cagri. This is for lifelong severe obesity that is now in remission after 55 percent body-weight loss, more than most trials have reported. The main reason to combine or push total GLP doses higher is when standard maximums plus time do not get weight into a normal range. There are probably higher risks of known and unknown side effects, yet the health dangers of remaining obese are worse, so the trade-off can still favor treatment. This kind of stacking has not been studied much beyond high-dose sema and cagrisema trials, which did not turn up new unexpected problems.

PlainMeadow18archiveJul 22
↳ replying to @LevelThistle44

When you moved from tirz to reta, did you begin reta at the same milligram amount you were using for tirz?

PatientBeacon78archiveJul 22

There are only so many GLP-1 receptors available, so raising exposure through one drug or several may not increase GLP-1 activity further and could instead affect GIP or glucagon pathways.

WarmKettle46archiveJul 24
↳ replying to @PatientBeacon78

I agree, and it will also raise the chance of side effects.

ClearBeacon24archiveJul 24

Reta’s glucagon activity does not begin until the 4 mg dose, so below that it acts basically like tirz.

SteadySparrow75archiveJul 24
↳ replying to @ClearBeacon24

That matches what I have been thinking, though some here have pushed back on the 4 mg threshold. I bought reta mainly for the glucagon fat-burning effect. I am close to goal but still carry a little belly that will not budge. Even after long hikes years ago that took me down to 170 lb there was still that apron of fat. I know reta is only part of the solution, but I will add resistance training and whatever else seems useful.

ClearBeacon24archiveJul 24
↳ replying to @SteadySparrow75

The video points out that the clinical trials support the 4 mg figure, so what is the issue?

SteadySparrow75archiveJul 24
↳ replying to @ClearBeacon24

I am convinced on the 4 mg point and want to reach it fairly quickly. I have room to lower the 10 mg tirz if reta sides stay manageable, so I can add reta on top of a reasonable tirz dose. I will split both and adjust from there. I have enough of each to last years whether I use one or both.

PatientCinder69archiveJul 24
↳ replying to @SteadySparrow75

Over a thousand miles on the Appalachian Trail in one go? That is impressive. I hike regularly and my family is surprised when I do five-mile walks every other day. Your numbers would amaze them.

BrightKettle28archiveJul 24

People also combine tirz and reta to boost results while lowering drug-specific sides, usually keeping doses below the individual maximums. In my case I tried it on myself to check for extra benefits and did not find any.

SteadySparrow75archiveJul 24
↳ replying to @PatientCinder69

Arizona has many trails to explore and I've always enjoyed that kind of activity. During the nineties when I had greater stamina and nerve I would prepare over several weeks then attempt the big canyon crossing twice in one go. The path covers more than forty miles while climbing above twelve thousand feet total. I finished those journeys inside eleven hours while the sun was still up. I repeated similar long day outings often yet skipped any overnight gear carrying. Reaching fifty nine made me realize it was now or never before my health or physician stopped me entirely so I headed out for two and a half months of it.

BrightSparrow36archiveJul 24
↳ replying to @BrightKettle28

Exactly. For me the stack has produced extra benefits. It can be useful to test things on yourself even when one approach does not pan out, since new options keep appearing.

PatientCinder69archiveJul 24
↳ replying to @SteadySparrow75

Well done. I want to be like that when I am older.

PlainMeadow18archiveJul 24

I have been on tirz and ordered reta hoping it would cut food noise better. I still have strong food noise, so I will see how the reta works once I try it.

LevelAlder29archiveJul 24
↳ replying to @ClearBeacon24

The video does not load here, but the title is Stop Wasting Retatrutide! Heres the Sweet Spot (Weightloss Dr. Explains) by Dr. Kevin Joseph.

LevelAlder29archiveJul 24
↳ replying to @SteadySparrow75

That is inspiring. I have only done day hikes in the Appalachians and prefer a bit more comfort, but I respect the determination.

GreyAlder39archiveJul 24
↳ replying to @SteadySparrow75

Did your doctor suggest sticking to shorter local trails instead?

SteadySparrow75archiveJul 24
↳ replying to @GreyAlder39

Squaw Peak is where I trained for the canyon hikes. I would work up over months and do multiple laps most days, totaling about 22 ascents and descents per week with 1,200 feet of gain each time.

GreyAlder39archiveJul 24

The published study shows roughly 25 percent greater weight loss between the 4 mg and 9 mg doses, which can shorten the time to goal by several months. I am not in a rush after carrying the extra weight for twenty years. I am currently on 10 mg reta and 10 mg tirz and have been at these doses for fifteen weeks including titration. So far I have lost 15 percent of my starting weight, BMI dropped from 32 to under 27, HbA1c fell from 10.5 percent to 7.5 percent, visceral fat is at 9 percent, and waist measurement has decreased.

CopperSignal27archiveJul 25
↳ replying to @ClearBeacon24

This does not match how drugs work. Receptor response to an agonist follows a stretched S-shaped curve. Retatrutide data show clear weight-loss effects at 1 mg (about 9 percent over a year), stronger at 4 mg (18 percent), and still more at 12 mg (29 percent). That places 4 mg well into the rising part of the curve, not at the start, so there is no special threshold where glucagon agonism suddenly begins. The claim is inconsistent with basic pharmacology and the actual trial numbers. The doctor in the video may have credentials, but the statement is incorrect and also conflicts with research favoring higher rather than very low doses.

ClearBeacon24archiveJul 25
↳ replying to @CopperSignal27

That is just your opinion and it means nothing. I see you are back after the ban.

ClearBeacon24archiveJul 25
↳ replying to @SteadySparrow75

There it is, just needs to be small enough to carry.

SteadySparrow75archiveJul 25
↳ replying to @ClearBeacon24

And there it is, just needs to be shrunk down and pocket sized.

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Those combining Reta and Tirz · ZyraTrack Community