Stacking Retatrutide with Tirzepatide — how do you cap the total?

[anotherusername]

If you're stacking Retatrutide with Tirzepatide, how do you keep the total GLP dose from climbing too high at the higher end? My instinct says the combined maximum ought to stay below 15mg, given that tirz alone tops out at 15 — but does Reta carry less GLP specifically? Anyone here run something like 12mg Retatrutide alongside 6-8mg tirzepatide for several consecutive months?

 

[Redz]

Loads of members are running high doses if you look around, though what I'm curious about is your reason for giving this a go? Has your loss stalled?

 

[woundcarping]

anotherusername said:

If you're stacking Retatrutide with Tirzepatide, how do you keep the total GLP dose from climbing too high at the higher end? My instinct says the combined maximum ought to stay below 15mg, given that tirz alone tops out at 15 — but does Reta carry less GLP specifically? Anyone here run something like 12mg Retatrutide alongside 6-8mg tirzepatide for several consecutive months?

With too little information behind it, you're overthinking this — meaningful conclusions aren't possible yet ("It seems to me that the maximum combined dose should still be under 15mg"). Titrate for efficacy, and let sides set the ceiling.

My weekly stack is 18mg of Reta plus .25mg of Sema. It's working delightfully. Tirz was where I started before moving to Reta, with a period of overlap back then. My final Tirz dose, 2.5mg, came on 3/12/26 while I was on 10-11mg of Reta.

 

[lessthanhalf]

My own regimen is 15mg of tirz plus 6 mg of reta, running about a year now, with 0.5 of cagri added more recently. The reason is severe lifelong obesity, currently in remission after 55% body weight loss — far beyond anything the studies have shown so far

Combinations, or total doses above the standard ceiling, have one genuinely good justification: severe obesity that standard maximum doses, given an adequate stretch of time — at least a year — fail to bring anywhere near a normal weight. Doing so almost certainly raises the risk of known side effects, and possibly of unknown ones, but the health toll of severe obesity is so brutal that those GLP risks look unlikely to exceed the risk of leaving the residual obesity untreated. Apart from the high dose semaglutide studies and the cagrisema studies there has been almost no study of this approach, and neither of those turned up any new unexpected adverse effects — mildly reassuring, though no proof it couldn't happen with other GLP's combined, given tirz/reta/cagri are the three most often paired.

Tirz/reta combinations do also get used to maximise the effects and cut drug specific side effects, though normally the doses involved sit below the maximum.

So in the end, going past the total recommended dose — whether through a high dose of one drug or through combinations — isn't really a problem. In practice almost nobody does it unless more is genuinely needed to control weight or hunger, and the situations where that arises are severe obesity, or perhaps the few percent who respond weakly to GLP's at standard dose. Unfortunately higher doses have limits: past the standard maximum, extra weight loss tends to shrink as the dose climbs, while side effects generally keep worsening. The 16mg semaglutide study did show a few percent extra weight loss, but much higher side effect rates.

 

[SecretMission]

woundcarping said:

anotherusername said:

If you're stacking Retatrutide with Tirzepatide, how do you keep the total GLP dose from climbing too high at the higher end? My instinct says the combined maximum ought to stay below 15mg, given that tirz alone tops out at 15 — but does Reta carry less GLP specifically? Anyone here run something like 12mg Retatrutide alongside 6-8mg tirzepatide for several consecutive months?

With too little information behind it, you're overthinking this — meaningful conclusions aren't possible yet ("It seems to me that the maximum combined dose should still be under 15mg"). Titrate for efficacy, and let sides set the ceiling.

My weekly stack is 18mg of Reta plus .25mg of Sema. It's working delightfully. Tirz was where I started before moving to Reta, with a period of overlap back then. My final Tirz dose, 2.5mg, came on 3/12/26 while I was on 10-11mg of Reta.

When you made the switch from Tirz to Reta, did Reta start at the same mg, or the same dose amount?

 

[Ontbijtkoek]

There are only so many GLP-1 receptors available to agonize, so raising exposure — whether via one compound or several — may achieve nothing on the GLP-1 side, and instead show up on the GIP or glucagon side.

 

[avidreaders]

Ontbijtkoek said:

There are only so many GLP-1 receptors available to agonize, so raising exposure — whether via one compound or several — may achieve nothing on the GLP-1 side, and instead show up on the GIP or glucagon side.

I'm with you on this, and it also raises the risk of adverse side effects

 

[Flash-BCR]

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

 

[woundcarping]

SecretMission said:

woundcarping said:

anotherusername said:

If you're stacking Retatrutide with Tirzepatide, how do you keep the total GLP dose from climbing too high at the higher end? My instinct says the combined maximum ought to stay below 15mg, given that tirz alone tops out at 15 — but does Reta carry less GLP specifically? Anyone here run something like 12mg Retatrutide alongside 6-8mg tirzepatide for several consecutive months?

With too little information behind it, you're overthinking this — meaningful conclusions aren't possible yet ("It seems to me that the maximum combined dose should still be under 15mg"). Titrate for efficacy, and let sides set the ceiling.

My weekly stack is 18mg of Reta plus .25mg of Sema. It's working delightfully. Tirz was where I started before moving to Reta, with a period of overlap back then. My final Tirz dose, 2.5mg, came on 3/12/26 while I was on 10-11mg of Reta.

When you made the switch from Tirz to Reta, did Reta start at the same mg, or the same dose amount?

woundcarping said:


I started Zep 12/12/25, I moved to compounded Tirz and was at 2.5mg 2x weekly until 1/10 when I moved to Reta. I took 7mg of Reta in total across 6 doses my first week. I've had 6 doses of Tirz since I started the bridge, totaling 14mg. I've had a total of 34 doses of Reta totaling 143mg. That averages 11.6mg/week with a chunk of that being getting my blood levels up using numerous small doses so I wouldn't overshoot and run into sides I had to wait out.

I moved to Reta for the GCGR signaling to boost BMR and presumptively spare lean mass better than Tirz.

GCGR signaling is dose dependent. Titrating Reta based on appetite/food noise is incorrect for reta, correct for Sema, Tirz, or Cagri. I titrated based on aversion to sides with the goal to get to or above 8mg/week levels for meaningful GCGR signaling.

I take Tirz PRN mainly to control food noise more so than hunger... my long term issue has been noise/brain side more than hunger/stomach side. I'll still take a bump if I expect the probability for trouble (like the 2.5mg dose in early March since I was traveling to either side of the country and back in 8 days).

Down 33lb since 1/10/25, 272lb to 239lb, practically all fat according to DEXA scans.

Had no meaningfully adverse sides.

Split dose, 2x weekly.

16mg/week with split dosing keeping my peaks only 15% higher than 12mg/once weekly (7mg 2x weekly has the same peaks).

RHR average hit a valley low of 58bpm on Tirz and is currently averaging 69-70bpm. This is inside my comfort level.

I don't expect 16mg to be magical over 12mg, but I do expect it to move my equilibrium point down ~10lb. That doesn't sound like much, but arguably that would be the hardest 10lb to lose. I chose to escalate my dose based on my sides and metrics including labs, fitness tracking, and sleep. I chose to do it now while I'm still resilient to the added stress vs later when systemic stress fatigue could be presenting.

Writing this post, I realized I failed to get labs on Lipase and Amylase to check my pancreas directly. My other labs suggest I'm doing fine, but gallstones/pancreatitis is my most likely hiccup. I'll get those labs drawn in the morning and report back if there's anything noteworthy.

View attachment 19076

View attachment 19081

Click to expand...

 

[CNCCurrency]

anotherusername said:

If you're stacking Retatrutide with Tirzepatide, how do you keep the total GLP dose from climbing too high at the higher end? My instinct says the combined maximum ought to stay below 15mg, given that tirz alone tops out at 15 — but does Reta carry less GLP specifically? Anyone here run something like 12mg Retatrutide alongside 6-8mg tirzepatide for several consecutive months?

My weekly combo is reta 6 mg with tirz 8.

 

[CNCCurrency]

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

 

[Flash-BCR]

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

 

[CNCCurrency]

Flash-BCR said:

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

He addresses that in the video — he says the clinical trial studies show it to be true. So?

 

[Flash-BCR]

CNCCurrency said:

Flash-BCR said:

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

He addresses that in the video — he says the clinical trial studies show it to be true. So?

yeah....count me as a believer in the 4mg and I want to reach the 4mg as fast as I reasonably can. There's plenty of slack in the tirz at 10mg to titrate down, so if the reta sides stay mild I'll simply take reta up to a proper dose....I'll split dose the tirz and reta and take it from there. I have enough of both to last years on one or the other....or both...

 

[PunctiliousKitten]

Flash-BCR said:

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

A full 1,000+ miles on the APPALACHIAN TRAIL?!?

What a blessing, sir. Like omg. All in one go?!

I hit the trails constantly, and my family are always impressed and shocked when I announce "chat later I'm going on a trail" and then manage 5 mile walks every other day. Your numbers would SCALP them! Sheeeshhh

 

[JoonyO]

The point above about tirz/reta combinations being used to maximise effects and cut drug specific side effects, usually at doses below the maximum, is one I tested on myself.

In my case, though, it was because I labratted meself to see whether any extra benefits showed up.

There weren't any. YMMV

 

[Flash-BCR]

PunctiliousKitten said:

Flash-BCR said:

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

A full 1,000+ miles on the APPALACHIAN TRAIL?!?

What a blessing, sir. Like omg. All in one go?!

I hit the trails constantly, and my family are always impressed and shocked when I announce "chat later I'm going on a trail" and then manage 5 mile walks every other day. Your numbers would SCALP them! Sheeeshhh

Arizona has no shortage of hiking and it has always been one of my passions....back in the 90's, younger and fitter and braver, I'd train for a few months and then tackle the Grand Canyon Rim to Rim to Rim...42 miles carrying 12,000+ft of elevation gain. Under 11 hrs, all in daylight...

So, I did plenty of that, but backpack hiking was new to me, so at 59 years old I figured I'd better do it now, before my body, or my doctor, tells me I can't...so off I went...2 1/2 months worth...

 

[ladyj779]

JoonyO said:

The point above about tirz/reta combinations being used to maximise effects and cut drug specific side effects, usually at doses below the maximum, is one I tested on myself.

In my case, though, it was because I labratted meself to see whether any extra benefits showed up.

There weren't any. YMMV

Indeed! Because additional benefits have shown up in my case. Being your own researcher and subject really does pay off at times — even when one thing turns out meh, new options come on line every couple months to try.

 

[PunctiliousKitten]

Flash-BCR said:

PunctiliousKitten said:

Flash-BCR said:

CNCCurrency said:

Flash-BCR said:

Tirz is my base, 10mg split dosed...in a couple 3 weeks I'll start working some reta in, going low at first to see how that goes. To my mind tirz and reta doses aren't equivalent 1:1, so my plan is to find the reta dose where the symptoms kick in and baseline from there...

Until you hit a 4 mg dose, Reta's glucagon side isn't doing anything. Below that, what you are taking is nothing more.

View: https://www.youtube.com/watch?v=oUL18iO18Oc&list=PLB_RSqpKtbEHo-3C3MCQTepuAIdG85KLs&index=111

That matches my thinking, though the 4mg claim has drawn push back here. I have a small pile of reta, bought mainly for the glucagon fat burning component. Goal weight is close, but like many people a little belly refuses to leave...Hell, 10 years ago I did 1,000+ miles on the Appalachian Trail and finished at 170lbs...and in the last photo someone took of me, there was the little belly apron...

I know there's far more to addressing the fat than reta alone, but I'll start the resistance work and anything else my research turns up...

A full 1,000+ miles on the APPALACHIAN TRAIL?!?

What a blessing, sir. Like omg. All in one go?!

I hit the trails constantly, and my family are always impressed and shocked when I announce "chat later I'm going on a trail" and then manage 5 mile walks every other day. Your numbers would SCALP them! Sheeeshhh

Arizona has no shortage of hiking and it has always been one of my passions....back in the 90's, younger and fitter and braver, I'd train for a few months and then tackle the Grand Canyon Rim to Rim to Rim...42 miles carrying 12,000+ft of elevation gain. Under 11 hrs, all in daylight...

So, I did plenty of that, but backpack hiking was new to me, so at 59 years old I figured I'd better do it now, before my body, or my doctor, tells me I can't...so off I went...2 1/2 months worth...

Bravo, young man! You're who I'd like to become

 

[SecretMission]

Triz is what I've been on, and I ordered Reta expecting it to help more with the food noise. Once I've tried the Reta I'll know, since my food noise is still ridiculous. Thanks for the info!