Switching from Mounjaro 12.5mg to Reta — what starting dose?

betterathalo

betterathalo

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I've looked through the forum, and I've looked through reddit too. If the answer is already out there and I overlooked it, I apologize, but my searches aren't turning anything up.

My brother's dad had been using Mounjaro. The cost became too much for him to continue. While he was on it, the results were great and he dropped a lot of weight.

Lately though, he's been having a hard time again, and he asked me about getting on what I use, which is Reta.

His Mounjaro dose was 12.5mg. With Reta, what dose should he begin with?
 
Came across this. I can't vouch for how reliable it is. That said, jumping straight to a high dose without tapering isn't something I'd do.





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betterathalo said:

I've looked through the forum, and I've looked through reddit too. If the answer is already out there and I overlooked it, I apologize, but my searches aren't turning anything up.

My brother's dad had been using Mounjaro. The cost became too much for him to continue. While he was on it, the results were great and he dropped a lot of weight.

Lately though, he's been having a hard time again, and he asked me about getting on what I use, which is Reta.

His Mounjaro dose was 12.5mg. With Reta, what dose should he begin with?
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Is he currently taking it, or did he stop?

How long has it been since his last dose?
 
Have him begin Reta at 2mg as a clean start, and stay at that dose for 4 weeks. 3 weeks is enough for it to clear out of his system.
 
On this one I agree with @BNLFL — begin him at 2mg, and stay there for at-least 3 weeks before any titration upward. He just needs to know that when it comes to suppressing appetite, Tirz does a far better job than Reta.
 
If you search for "bridge" along with my username, you'll find the story of how I moved off 5mg Zepbound/Tirz and onto Reta back in January. Going straight from 12.5mg down to 2mg isn't something I'd do, though my own targets, what I can tolerate, and the fact that I'm a math nerd could make my situation different from yours.
 
woundcarping said:

If you search for "bridge" along with my username, you'll find the story of how I moved off 5mg Zepbound/Tirz and onto Reta back in January. Going straight from 12.5mg down to 2mg isn't something I'd do, though my own targets, what I can tolerate, and the fact that I'm a math nerd could make my situation different from yours.
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fwiw I know someone who was on 15mg of Tirz for more than a year and quit it abruptly. Since his insurance was gone, Tirz wasn't an option, so I helped him switch to Reta. He ran Reta at 3mg per week. After about 2months off Tirz, when he restarted it alongside Reta, he began at 6mg with no problems, then bumped to 9mg in week 2.
 
betterathalo said:


He was on 12.5mg of Mounjaro. What should he start at with Reta?

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Since he's already been sensitized to tirz, his body has already seen glp1 and gip agonism, so the hunger he's feeling is likely that. What sets it apart is the glucagon agonism, and that's what will push your heart rate up. That part can't be avoided.

For me, when I switched, I jumped from 15mg tirz directly to 8mg and had no problems at all. An option is to begin at 2mg and then raise it by 1mg every 2 weeks, checking hunger suppression as you go and adjusting from there. In my view, a 4 week interval isn't needed for someone who's already had exposure.
 
I've been maintaining since May 2025. I put this up somewhere before..... what others find in their own research can be different.

I was on Tirz for almost exactly 1 year, to the day (May 30th 2025, if I remember right, was my final day). For 5 months my ceiling was 15mg. (about January 2025- May 2025.) Most of my weight came off between May 2024 and December 2024, the stretch when I moved from 12.5 up to 15mg). The final 20lbs to reach my goal happened once I was at 15mg Tirz.

During my last 2 weeks on Tirz, I stepped down to 10mg and added .125 cagri. The following week I stopped the Tirz entirely, started 1mg Reta, and used .25 Cagri for maintenance. A couple weeks later I moved up to 3mg Reta.

I stopped Cagri in November 2025. Without meaning to, I lost about 15 more lbs while maintaining. I'm still running the Reta 3mg 1x per week protocol for maintenance. My weight holds steady, and I'm able to enjoy food.
 
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