CommunityDosing & Titration

Starting Reta after switching from Tirz - starting dose question

16 replies14 peopleMar 6, 2026☆ Follow
Summary

What starting dose of retatrutide should someone use after being on tirzepatide?

Users switching from tirzepatide report trying initial retatrutide doses from 0.5 mg up to 2 mg, with some feeling effects quickly at lower amounts and others needing to increase before noticing changes. Experiences vary on side effects like nausea or appetite shifts, and most follow gradual titration similar to trial schedules. Some switch cold turkey while others consider overlap, but results depend on individual response.

What this discussion establishesWhere people disagree

Some prefer very low starts to minimize sides while others find conservative dosing unnecessary and suggest using roughly two-thirds the prior tirzepatide dose right away.

Still open

Whether an overlap period with both medications is needed or beneficial during transition

Nothing here is advice.

16 replies · 14 people
PatientLedger30archiveopening postMar 6

Received my first supply of Reta and trying to decide between beginning at 0.5 or 1.0. I've been taking 5.0 mg of Tirz for almost a year, so considering starting low with Reta and adjusting from there.

WarmHarbour52archiveMar 7

From what I have read

ClearBeacon24archiveMar 7

Thanks, will check it out

KeenWillow90archiveMar 7
↳ replying to @PatientLedger30 (opening post)

I began with a dose of 1.5 and noticed the effects clearly. After roughly three weeks at that level, I increased to 2 milligrams. I've maintained the higher amount now for five weeks. The response from my system to starting small and gradually raising the amount appeals to me. I'm uncertain about my eventual level but looking forward to continuing this process.

SlowSignal37archiveMar 7
↳ replying to @KeenWillow90

Have you kept taking tirz or stopped ahead of Reta?

WryBramble37archiveMar 8
↳ replying to @PatientLedger30 (opening post)

After three months on the 2.5 Tirz dose I jumped straight across to 2 milligrams of reta without any taper. That starting level came across as slightly less effective at first. Once a month had gone by I moved the reta amount up to 4 milligrams and it finally delivered the results I was after.

NorthCinder24archiveMar 8

Began with a small amount and noticed zero changes. The following week I raised the dose a bit and sensed some mild effects. Then increased it again the week after and the reaction felt overwhelming. Eating became tough during that time because of nausea. This was my first experience with anything similar. Later I started dividing the doses and now take a larger weekly total while the weight keeps coming off.

SteadyPebble62archiveMar 13

Up to the previous week I had been taking the prior compound through nearly all of February, finishing the last fortnight at the 3 milligram level. Starting Monday March 9 2026 I moved to the newer option at 2 milligrams and intend to hold there through next month before considering a step to 4 milligrams if it seems warranted. I matched the gradual increase pattern shown in the latest research trial. On the side effects side my sleep has not felt as restful as it did previously and I felt slight queasiness this morning after skipping breakfast. I also find I can handle somewhat bigger portions now which helps since I must reach a high daily protein target from strength training sessions where I used to face real difficulty.

SlowLantern27archiveMar 13
↳ replying to @SteadyPebble62

I didn't leave out carbs when I took Reta either.

GreenWillow85archiveMar 13

Anyone switched from that fifteen milligram amount of MJ straight onto Reta? What kind of results showed up after the change? Did the process begin at a reduced level as well?

At the moment I'm trying TIRZ and recently picked up MOTS-C to combine with it, yet the scale shows zero movement after several months despite sticking to every correct step, so maybe a switch deserves some thought.

LevelThistle41archiveMar 24
↳ replying to @PatientLedger30 (opening post)

How did that turn out for you? I've stuck with 2.5mg of tirz on alternating days starting back in June of last year, and lately I've been considering a switch over to reta.

NorthLantern91archiveMar 24

I've been wondering about the experiences of people moving from tirzepatide over to retatrutide. I'm thinking of making that move myself when I reach my target weight. Do people usually have some time when they use both, like beginning with a small amount of the second while cutting back on the first? Or do they typically just switch directly from one to the next?

CopperSignal27archiveMar 25

My take comes from scanning various research papers plus discussions I've noticed in online groups. One straightforward low-risk approach involves taking two-thirds of the prior amount when switching over, like going from fifteen milligrams down to ten. To play it safer, half might work better. Going even lower than that does not appear needed. Nothing ensures fewer reactions during the change because people respond uniquely to these compounds, though problems probably won't arise. This one tends to raise pulse slightly higher compared to the other, meaning anyone with cardiac issues should avoid it since research is lacking or proceed with tiny gradual steps. It carries minimal danger while avoiding the long process of gradual adjustments over many months. After experiencing the initial one or two injections, reactions will clarify personal tolerance and guide future adjustments.

Add your experience

If you have tried it, this topic is still open. Sign in to reply — it takes a minute.