Tirz or Reta... or Switch?

Green-FWIW

Well-known member
I have about a quarter year's worth of compounded Tirzepatide remaining, and my fresh Retatrutide arrived recently. Can't decide whether to switch immediately or finish the Tirz first. Started losing weight in March '25 at 236, began Tirz at 205 around September, and currently weigh around 177. Losing roughly 4-5 pounds a month, which isn't amazing, but not terrible either.

Considering switching for potential liver perks, a possible boost in weight loss, and maybe to alleviate the general fatigue I've experienced with Tirz.

Has anyone noticed a faster weight loss rate after switching? How do the side effects compare?
 
If you're set on using up the tirz but the tiredness is getting to you, lots of folks add a TINY bit of Survodutide to their tirz. Might be worth researching. Like, 0.3 mg per week to start, then 0.6 after a month, and not much more. I don't grok the science, but it seems to work for me.
 
Why not both?! LOL. I stack them, just for weight loss. They call it "burn blend" in some places, and it does just that 🔥
 
Finish what you have, you're still dropping lbs. People also mention reta fatigue, so it might be even worse than what you're feeling now.
 
Reta can make you feel just as crummy, honestly. The studies show fatigue levels are similar between tirz and reta.

Reta might be overhyped except for the liver benefits. If you have a fatty liver, reta could be the better/faster choice.

Studies do indicate quicker weight loss with reta, but you need to reach a higher dose. Some individuals even gain a little at first when switching.

Reta isn't a miracle for preventing muscle loss. Some research even suggests a greater percentage of muscle loss with reta compared to tirz.

Anyone with heart conditions should avoid reta until it's FDA approved.
 
I stacked during my Reta transition, then went solo on Reta, and now I'm stacking again. I switched because Tirz alone gave me extreme fatigue, zero appetite (unflavored protein in coffee was the only way to get protein), and terrible constipation. If you stack, start low! Those with elevated heart rates often start too high or increase too quickly. I began with 1 mg Reta and 8 of Tirz. My sweet spot (best weight loss/fewest side effects) was 4 mg/4mg weekly.

Common sense is enough to use Reta. I have AFib and haven't had any issues. Start with a low dose, wait a month between increases, and you should be fine. Any GLP has the potential to raise your resting HR.

Sorry you had a bad experience with Reta - it was a relief to regain energy. It doesn’t seem to suppress appetite as much as Tirz for a lot of folks, but fortunately I haven’t had that issue. My problem is I’ve lost weight more slowly on Reta... but I've also switched to eating more whole foods instead of relying on protein shakes. I'm not sure about muscle loss, but my smart scale says I've gained some muscle, and I've also become more active since the fatigue is better.

Overall, it's a good choice. Here's what I'd do in your shoes:
-If no bad side effects, maximize weight loss using Tirz first - reach the highest effective dose and then switch.
-If you want to switch for fatty liver or faster losses and don't want to wait, stack them. Don't waste your Tirz.
-If the side effects become unbearable, stack - you'll get some relief as the Reta dose increases. And I lowered my Tirz dose while increasing Reta. Stacking may work for you- a lot of people like it.

Whatever you choose, be careful. Good luck!
 
I stumbled across a Reddit thread where someone said they worked out intensely, were in a calorie deficit, and still gained weight on GLP-1s. Sounds like they might need to speak to an endocrinologist and get some tests done, because that doesn't sound right at all.
 
Thanks for that. Not from reddit. Took 4 weeks searching before finding this forum. Even had to switch to DuckDuckGo. Really excited about peptide knowledge so far.
 
Reta treating you better than the other two is huge. Heart rate elevation is worth monitoring closely though. How high did it go for you?
 
You mentioned that recently and it made sense. Switched my tirzepatide to four-day gaps. Really sustainable, keeping peaks and dips steady helps rhythm.
 
Ten years of Tirz with Reta and Klow built in is the long-game most people never reach - the switch question at a quarter-year is a different frame entirely.
 
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