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Debunking the 4mg Retatrutide Glucagon Threshold Claim

38 replies15 peopleMay 20, 2026☆ Follow
Summary

Does retatrutide's glucagon receptor activity only begin at 4mg weekly, or is that a myth based on misinterpreted trial data?

The thread shows the 4mg claim stems from misreading single-dose phase 1 data where glucagon changes appeared around 3mg, later rounded up, without accounting for weekly accumulation or individual variation. Users report meaningful weight loss and waist reduction at 1mg, while others see stalls resolved only after moving to 6-8mg. Waterfall plots highlight wide personal differences, and higher-dose groups had not yet plateaued at 48 weeks. Some note fatigue limits upward titration regardless of the myth.

What this discussion establishesWhere people disagree

Whether the glucagon component adds unique benefits at higher doses or whether low doses already capture most effects for many users.

Still open

Optimal long-term dosing for athletes or highly insulin-sensitive individuals and how reta interacts with very low-carb diets over extended periods.

Nothing here is advice.

38 replies · 15 people
SlowLedger42archiveopening postMay 20

Saw this claim surface again and thought a clear post on it would help. People often say reta behaves like tirzepatide below 4mg because the glucagon part supposedly stays inactive until then. That idea traces back to a misread of phase 1 single-dose data. The 3mg single-dose group showed the first clear drop in serum glucagon, and someone later rounded it to 4mg since phase 2 skipped that exact level. The logic falls apart for two reasons. First, a single 4mg dose roughly matches the peak from a weekly 2mg schedule, while weekly 4mg would keep levels swinging between roughly 8mg and 4mg. Second, there is no basis for assuming the effect turns on uniformly for everyone at one number.

IronThistle53archiveMay 20

Solid post. I was under the impression I had to push straight to 8mg before anything meaningful would happen. I'll stay at 6mg as long as progress holds.

NorthSparrow68archiveMay 20

Results clearly differ between people. I've been at 1mg for nearly 11 weeks, started at 328 pounds and dropped 25 so far, which puts me ahead of the trial averages at that dose. Waist is down four inches too. For me the dose is already affecting visceral fat, though I'm also eating differently and lifting three times a week.

SlowLedger42archiveMay 20
↳ replying to @NorthSparrow68

Yes, the spread from person to person is large. The waterfall plot from the phase 2 trial shows each individual's result lined up from lowest to highest within each dose group so the range is visible.

NorthSparrow68archiveMay 20
↳ replying to @SlowLedger42

That plot makes the jump from 1mg to the higher groups stand out. Once past 4mg the lines for most people look pretty similar through 12mg.

IronThistle53archiveMay 20

Thanks. Looking at those graphs, the biggest gains for the largest number of people seem to sit between 4 and 8mg, with smaller additional gains after that.

SlowLedger42archiveMay 20
↳ replying to @NorthSparrow68

If the goal is to compare average outcomes across doses, the original average plot in the first post shows that more clearly than the waterfall version.

SlowLedger42archiveMay 20
↳ replying to @IronThistle53

Diminishing returns are likely, but the 48-week data still had the 8mg and 12mg lines climbing, so they had not leveled off yet.

IronThistle53archiveMay 20
↳ replying to @SlowLedger42

Fair point. Trials have to wrap up eventually when investors want data. It does make me wonder how much further the higher doses could have gone with more time. The compound is strong and the real-world numbers are compelling. Excellent post, appreciate it.

PlainAlder11archiveMay 20
↳ replying to @IronThistle53

I planned to stay at 6mg for a while as well. The first four weeks at 6mg went well, but the last two slowed noticeably. Two weeks at 7mg did not change much. Moving to 8mg felt like starting over, with renewed effect after the first injection.

QuietThistle43archiveMay 20

I titrated to 8mg fairly fast based on the same incorrect information. With the corrected view I think 4mg may be plenty to finish the last 15 pounds toward a 100-pound total loss. I'm already down 85 pounds.

QuietAnchor73archiveMay 20
↳ replying to @SlowLedger42 (opening post)

Thanks. The 4mg idea pushed me to keep raising the dose out of worry that lower amounts would miss the intended effects. The urge to fix years of issues quickly is hard to ignore.

PatientTimber45archiveMay 20
↳ replying to @PlainAlder11

I've been chasing that same renewed feeling for three weeks now. Next week will decide whether I stay or drop back because of stomach issues.

KeenCompass55archiveMay 20
↳ replying to @IronThistle53

So the claim is that something notable occurs at 4mg, but it is not the sudden start of glucagon agonism?

RustKettle12archiveMay 20
↳ replying to @SlowLedger42 (opening post)

Thanks for laying this out. I've been on 1mg per week split into two doses for nine weeks with solid results. When I tried 1.4mg the fatigue and impact on training became too much, so I returned to the lower amount. The repeated 4mg statements made me wonder if I was missing the glucagon part, especially since I doubt I would tolerate or reach that level. For reference I'm female, 5'10.5", started at 162.4 lb and now at 138.8 lb after nine weeks. Planning to begin lowering toward maintenance to address perimenopausal gain.

PlainAlder11archiveMay 20

I still don't understand where the idea of very low doses came from or why they seem to work. No offense to anyone using them, but 2.7 pounds a week on 1mg does not track for me.

SteadyCinder47archiveMay 20
↳ replying to @IronThistle53

How long did you stay at 4mg before moving to 6mg?

RustKettle12archiveMay 20

Interesting. I've seen scattered reports from lifters using it for cuts but no consistent pattern yet, and the trial data does not cover that demographic well. 5mg tirzepatide stacked with 3.5mg reta is quite a combination. Had you used any GLP-1 before this current approach?

PatientAlder89archiveMay 20
↳ replying to @RustKettle12

I've seen the same comments about strong results on low doses. There may not be a single answer. I started in February and still have not reached even 15 pounds lost. I'm grateful this is the most progress in years, but 40 pounds remain. I've tried everything previously with no appetite: multiple daily gym classes including kickboxing, yoga, pilates, barre, swimming, sauna, boot camp, measured food, intermittent fasting, gluten-free for three years, and even prescribed phentermine produced only a few pounds.

RustKettle12archiveMay 20
↳ replying to @PatientAlder89

That history sounds frustrating, yet the consistency is impressive. Back in 2016 I weighed nearly 300 pounds, switched to low carb primarily for epilepsy, and lost 160 pounds in under a year. I got into training because the lighter weight made movement easier, and diet was always the main driver rather than exercise for fat loss. Kept the weight off for almost a decade until perimenopause added about 25 pounds, which is why reta has been helpful. The current challenge is forcing enough food to support training and weekend hikes.

PatientAlder89archiveMay 20
↳ replying to @RustKettle12

I like that story and the photos look genuinely happy. One trainer I followed always said results are 80 percent kitchen and the workout is the bonus. Same here with no appetite and nothing sounding appealing.

SlowLedger42archiveMay 20
↳ replying to @RustKettle12

Small world. I recognize the background from low-carb circles and recall the first COSCI event in Vegas. It is interesting how this group has taken interest in reta after largely avoiding earlier GLPs. The glucagon angle felt worth exploring. I have a working idea that people who are already quite insulin sensitive tend to feel more initial fatigue on reta.

RustKettle12archiveMay 20
↳ replying to @SlowLedger42

That is funny. I've been active in keto, carnivore, and low-carb spaces since 2016. I keep the current experiment private because of the gray-market aspect. Reta was the first GLP that caught attention here, partly because a few respected voices started looking into it. Strength has held up similarly to other calorie deficits. The real issue is eating enough to support training and long hikes. When I raised the dose to 1.4mg the fatigue became noticeable again.

IronLantern24archiveMay 21
↳ replying to @NorthSparrow68

I actually did better at lower doses. Now at 5mg it feels like things have leveled off, possibly because the body has adjusted. I had already been losing on low carb before starting and then heard the carb advice online so I stopped.

PatientAlder89archiveMay 21
↳ replying to @RustKettle12

The idea that reta needs carbs may be individual. I know someone active who stalled until they added more carbs back in.

SlowLedger42archiveMay 21
↳ replying to @RustKettle12

Amber's recent posts caught my eye too. She presented at the COSCI event I attended and mentioned ongoing weight struggles, which stood out in that crowd. I have not been very active in the space lately but learned a lot there. With more people now discussing reta it might be worth checking in again, though deeper investigation would be useful because the metabolic framework in that community could add context the mainstream coverage lacks.

RustKettle12archiveMay 21
↳ replying to @SlowLedger42

Yes, Bikman's recent videos on the topic are worth watching. He has been shifting from viewing these drugs mainly as a bridge to low-carb eating toward examining the actual internal changes. His take on why simply saying "GLPs increase insulin" is incomplete lines up with what I have observed. I also tracked blood glucose closely at the start and saw no major dips. Electrolytes have needed a noticeable increase beyond the usual low-carb amounts.

SlowLedger42archiveMay 21
↳ replying to @RustKettle12

Bikman started with the temporary-aid view but has moved to asking what is actually happening inside users. I agree the carb theory is likely individual. My own ketones rose briefly in the first three weeks then returned to the usual low level for my intake pattern. With body fat now low, there is simply less to mobilize.

RustKettle12archiveMay 21
↳ replying to @SlowLedger42

Amber is a friend and might be open to discussing it. Reddit conversations on the topic tend to shut down quickly. My ketones moved from the usual 0.3-0.5 range up to 1.2 early on then settled back. With current body-fat levels there is limited room left for further loss, so microdosing for the other effects is the next step.

SlowLedger42archiveMay 21
↳ replying to @RustKettle12

There are occasional decent threads on Reddit, though they are rare. One subreddit that stayed thoughtful for a while was the saturated-fat discussion group, which moved from one extreme diet idea to exploring high-carb low-protein low-fat approaches while keeping a mix of viewpoints rather than becoming an echo chamber.

RustKettle12archiveMay 21
↳ replying to @SlowLedger42

I know Brad through a friend who tried the croissant diet and some heavy-cream experiments. That friend experiments more aggressively than I do.

SlowLedger42archiveMay 21
↳ replying to @RustKettle12

You might still find value in following that heavy-cream experiment even if the tone is rough. The documentation was thorough and the outcome was striking for a very unconventional approach. Brad might bring interesting angles if he ever tried reta, though it could also end his drive to invent new dietary frameworks.

RustKettle12archiveMay 21
↳ replying to @SlowLedger42

The delivery was off-putting enough that I stopped engaging. Still, the heavy-cream results were notable for how extreme the method was while producing clear loss.

SlowLedger42archiveMay 21
↳ replying to @RustKettle12

He does call himself the same term at times. The heavy-cream log was memorable simply for proving such an extreme intake pattern could drive substantial loss. Hopefully more people from that community will explore reta and bring their usual level of detailed tracking.

NorthSparrow68archiveMay 22
↳ replying to @SlowLedger42

Averages are meant to smooth variation, and the smoothed view still shows the clearest separation between 1mg and 4mg, with smaller further gains after that.

ClearLantern81archiveMay 22

This post stands out for staying closer to actual physiology than most forum claims. The note that unchanged glucagon readings at lower doses could reflect feedback balance rather than absent activity is a sharp observation. Endocrine systems compensate, so an agonist can still be active even when measured levels look normal.

SlowLedger42archiveMay 22
↳ replying to @ClearLantern81

It is interesting to see the original post translated out and back and still carry the intended meaning without distortion.

CopperAlder25archiveMay 22

Good post overall. The 4mg figure comes from a quick reading of the phase 1 single-dose data and does not translate well to weekly dosing. The glucose data at low doses show little net change, which fits with balanced GLP-1 and glucagon activity plus individual sensitivity. The insulin-to-glucagon balance section is where the argument feels strongest.

CopperCompass77archiveMay 25
↳ replying to @NorthSparrow68

When I was heavier, small diet and activity changes produced big results. It is good to see steady effort rather than rushing. At this stage the medication may be contributing less than the personal habits, which is fine. It can get harder later, at which point a higher dose might help or might not be needed. I reached a stable point years before these drugs existed, then regained some weight and chose to use one rather than fight it alone. The joint relief has been an unexpected bonus that makes staying active easier.

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