CommunityFood & Appetite

Reta making me extremely hungry

32 replies11 peopleFeb 28, 2026☆ Follow
Summary

why does retatrutide sometimes increase hunger early on especially after switching from tirzepatide

Users report that low doses of retatrutide (under 4 mg) produced stronger hunger than being off medication entirely, with some attributing it to glucagon agonism appearing before full GLP-1 effects. Others note that meaningful appetite suppression typically begins around 6-8 mg and that prior tirzepatide use may blunt early response. Several participants observed that weight loss can still occur even without strong hunger reduction, and that rushing titration or freezing reconstituted peptide carries risks. The thread leaves open whether the early hunger phase is common or batch-related.

What this discussion establishesWhere people disagree

whether early hunger increase is a normal mechanistic phase or indicates under-dosing or degraded product

Still open

whether the user's specific batch is under-strength or whether prior tirzepatide created lasting tolerance that delays reta effects

Nothing here is advice.

32 replies · 11 people
PlainCompass18archiveopening postFeb 28

I used Mounjaro last year for eight months, starting low and working up to 10 mg, and dropped 30 kg without dramatic appetite wipeout but easier control especially at night. After a month and a half off I began retatrutide. I got a 40 mg vial instead of the 30 mg I wanted, added 2 ml bac water, pulled 1 mg into a pen cartridge, then filtered another 2 ml into the same cartridge for a total of 20 mg in 3 ml. After losing some volume to priming and leaks the concentration stayed the same. I started with 0.5 mg Monday, another 0.5 mg Wednesday, then 1 mg the following Monday and another 1 mg that Wednesday. Instead of lowering hunger it has made it stronger than before any GLP-1 use.

LevelThistle44archiveMar 1

You were on 10 mg tirzepatide for months and now you are using 1 mg twice a week, so hunger is no surprise. Your mixing steps also look odd and probably contain a typo.

PlainCompass18archiveMar 1
↳ replying to @LevelThistle44

I get that. While off tirzepatide for nearly two months I felt normal, but now hunger is actually higher than before any GLP medication. The mixing looks strange because I bought a 40 mg vial by accident. To avoid waste I reconstituted and used only half of it, 20 mg, and froze the rest for later.

PlainAlder11archiveMar 1

I reconstitute 40 mg reta with 4 ml bac water. I began at 2 mg and appetite dropped sharply right away.

PlainCompass18archiveMar 1
↳ replying to @PlainAlder11

The pen cartridge I have only holds 3 ml total.

LevelThistle44archiveMar 1

Recency bias might be playing a role; it is unusual for reta alone to increase hunger. What is your weight doing, any sides, and what are your goals? Why switch from tirz? The simple fix could be to increase the reta dose and watch what happens.

IronThistle53archiveMar 1
↳ replying to @PlainCompass18

Out of interest, do you think the reconstituted reta lost potency after time in the freezer?

LevelThistle44archiveMar 1

Given he has only been on it two weeks and reports the worst hunger yet, he probably lacks a clear baseline.

PlainCompass18archiveMar 1
↳ replying to @LevelThistle44

I went from 105 kg down to an unhealthy 78 kg, then after Christmas and a Japan trip I was back to 85 kg. No sides at all on either drug. Body fat fell from 32 % to 18 %. Goal is under 15 %. I switched because Mounjaro was too expensive. I swim and lift four times a week plus tennis and cycling. I plan to go up to 4 mg.

PlainCompass18archiveMar 1
↳ replying to @IronThistle53

I am not using the frozen portion, only the other half.

PlainMeadow15archiveMar 1

From what I have read, hunger suppression on reta usually appears around 8 mg. I tried it a few months then switched back to tirzepatide because I was not losing and actually wanted to stop losing. Reta also lacks the inflammation reduction I get from tirzepatide.

PlainCompass18archiveMar 1
↳ replying to @PlainMeadow15

Okay. I hoped the third pathway would make a big difference. I will keep going for a while. Part of me wonders if the batch is weak, since even 1 mg of Mounjaro gave me noticeable effects.

IronThistle53archiveMar 1
↳ replying to @PlainCompass18

That makes sense. Research says reconstituted peptide does not hold up well after freezing, though some users report only slight loss. My own test subject will show results in a few months and I will post separately then.

IronThistle53archiveMar 1
↳ replying to @PlainCompass18

From what I have read the glucagon receptor does not really engage until above 6 mg, though some feel effects sooner. I am only at 3 mg this month and will move to 4 mg next month.

PlainCompass18archiveMar 1
↳ replying to @IronThistle53

That is a long wait if you follow the usual schedule. I plan to reach 4 mg by week three. I suspect prior tirzepatide use may have built some tolerance, but time will tell.

QuietFenwick11archiveMar 1
↳ replying to @PlainCompass18

Do not freeze reconstituted retatrutide. Use the whole vial; degradation is minimal even at 60 days. Filtering is wise because bacterial growth becomes the main concern after four weeks.

KeenAlder60archiveMar 1
↳ replying to @PlainCompass18

It takes a full month for steady-state levels. Increasing every three weeks means you never reach full effect. Dosing by feel is risky. Give each dose time.

PlainCompass18archiveMar 1
↳ replying to @KeenAlder60

Do you think my body is already adapted to GLP drugs from Mounjaro?

KeenAlder60archiveMar 1
↳ replying to @PlainCompass18

That does not change how these drugs behave. It is not about getting used to GLP drugs; the pharmacokinetics are the same for everyone.

PlainCompass18archiveMar 1
↳ replying to @KeenAlder60

I understand the standard timeline, but responses vary. Some notice effects at 0.5 mg while others need 8 mg and several months. I will update once I reach 4 mg.

LevelThistle44archiveMar 1
↳ replying to @KeenAlder60

You can reach higher accumulated levels faster than waiting four or five weeks at each step. I went from zero reta to over 9 mg peak in 18 days while still clearing tirzepatide, and I am now seven weeks in at 4 mg twice weekly.

CopperSignal27archiveMar 1

No solid pharmacology explains stronger hunger on reta than on nothing for two months. Glucagon could theoretically raise appetite but the combined GIP and GLP-1 agonism should offset it. You are still on a very low dose. Studies show reta produces substantial weight loss even at 1 mg weekly. Most users say it curbs hunger less than tirzepatide, yet the scale results contradict that. The extra energy burn from glucagon is only about 100-200 kcal daily at higher doses, enough to account for the difference versus tirzepatide. If you do not want to stop, the obvious next step is to raise the dose.

WryBramble37archiveMar 1

I switched straight from 2.5 mg tirzepatide to 2 mg reta and held steady or gained slightly for four weeks. At 4 mg weekly the second dose made me hungrier yet fat loss accelerated dramatically. Body fat dropped from 13 % to 11 % and I overshot my goal weight. Hunger control was weak but the scale moved. I am now micro-dosing for maintenance. Most people find their effective level; just titrate slowly and wait for each dose to stabilize before going higher.

KeenAlder60archiveMar 3
↳ replying to @LevelThistle44

Just because it is possible does not mean it is advisable. Some people do it, but that does not prove safety.

PlainCompass18archiveMar 5

Retatrutide hits GLP-1, GIP, and glucagon receptors. GLP-1 normally reduces appetite while glucagon raises energy use and can increase hunger. This raises the possibility of a temporary window where glucagon effects appear first, especially if prior tirzepatide use has already created some GLP-1 tolerance. Trials overall show reduced appetite, so this is not proven, but I am asking whether the mechanism could explain early increased hunger and whether others switching from tirzepatide or semaglutide have seen the same pattern.

WarmLedger65archiveMar 5

I also had increased appetite when I started reta. It eased after a couple of weeks and now I only get occasional very hungry days while still losing fat. I assume it is the glucagon effect.

IronThistle53archiveMar 6
↳ replying to @QuietFenwick11

Too late, it is already frozen and thawed. I have added bac water and will dose my test subject next week to see what happens.

CopperSignal27archiveMar 6

Repeated freeze-thaw cycles degrade peptides. One cycle might cause only a few percent loss, which would not be noticeable in practice. Even at 5 % loss the difference in a 5 mg dose is too small to matter.

IronThistle53archiveMar 6
↳ replying to @CopperSignal27

Thanks, that matches some of the advice I have seen. If my test subject survives I will report results over the coming weeks.

QuietFenwick11archiveMar 7

It is a shame to waste this drug on rats.

SteadyQuill55archiveMar 7
↳ replying to @QuietFenwick11

Rats rarely get fat unless given a high-fat diet and limited space. I used to let mine run free in the evenings; they would come back when I shook a peanut bag. That was in the early 2000s so no photos, but my ex still recalls seven rats waiting in a circle for their bedtime peanut.

CopperSignal27archiveMar 7

Plenty of obese rodents exist in labs on 60 % fat diets, and thousands have received reta for obesity studies. They end up dissected after weight loss, but testing on them first is still preferable to starting with humans.

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