Appetite suppression without desensitization: Setmelanotide and the MC4R-Kir7.1 complex

frenexen

Member
Hey guys, I'm writing this up to share my interest and subsequent experience with setmelanotide.

Most appetite suppressants work through GCPRs that are subject to desensitization; mainly dopamine, glp, gip, and glucagon. Since the MC4R is also a GCPR I thought it would be subject to the same desensitization, with setmelanotide showing long term effects only because it was meant to be used in individuals with genetic abnormal signaling.

However, upon further research, I found that the appetite suppressant effects of the MC4R actually come from inhibition of the Kir7.1 channel. Notably, although this channel closes in response to the MC4R, it's closure is dependent on activation alone and is not altered by receptor desensitization. https://www.science.org/doi/10.1126/scisignal.aab2761

My experience:

Approved dosages for genetic obesity is 1-3mg. I found 3mg once per day to cause minor nausea but not really stop me from eating. I found my max dose to be 9mg per day. This is slightly under HEDs used in animal testing without genetic abnormalities. I have not tried any higher as I am barely able to hit protein targets as it is. At this dose it is very difficult to hit 2500 calories. I've lowered it to 6mg. At this time I also completely stopped using semaglutide and retatrutide, at which I was at the max weekly dose for both. I have yet to notice any tolerance after a month of usage at the same dose. Setmelanotide lacks the long half life that the incretins do which facilitates progressive accumulation, so if it did cause desensitization you'd likely notice it much sooner.

I found the appetite suppressant effects to be more similar to stimulants than incretin peptides. It is honestly not enjoyable at all as it mostly just feels like constant mild nausea, but I never felt like I had to vomit. The key is to find the dose that causes you to be disinterested in food while not causing significant nausea. It doesn't make you full quicker, rather it makes you more likely to not eat in the first place.


Side effects

- ~5 point increase in systolic bp.

- Reflux, not as bad as GLPs but still there.

- The first few times I had stomach pain, mildly sharp, that lasted for 5-10 minutes. This appears to be a known side effect.

- I felt very 'tight' in that I had a desire to stretch and yawn a lot, especially in the morning. This actually really sucked in the beginning but is completely gone now. My joints felt very brittle and it felt more difficult to open things. It didn't make me weaker when working out though- it was definitely all psychological. This was clearly from initial potent MC4R activation that is now desensitized.


Most alarmingly is that inhibition of the kir7.1 channel may be dangerous for the eyes. From everything I could find, I do not believe this receptor-channel interaction occurs in the RPE. Although both kir7.1 and the MC4R are present in the eye, they don't seem to be located in the same types of tissue. There has been zero cases reported for blindness in the extensive years of trials, but nevertheless it is listed as a potential side effect, as it has not been proven definitely that this interaction does not occur. Additionally an FDA panel concluded that it likely does not cause eye related issues.

What we can at least infer is that kir7.1 blockade should only be done through MC4R inhibition for the possibility that it is localized to the brain, and not through a direct channel blocker that would function systemically.

I did not notice much tanning, also likely because of rapid desensitization. MT2 always made my face extremely orange anyway so this is a plus for me. I did notice more moles however, similar to MT2. Your experience may be different if you use slowly ascending dosages instead.

Cost is not too bad if you use raws. I paid $180 for 1 gram.

When I do stop using I'll update with side effects of coming off, and also update if I do notice any tolerance develop.
 
Update for those interested.

As the semaglutide and retatrutide continue to leave my body I decided to make it more difficult by adding 24IU of HGH, have been off this for about 6 months. I usually get ravenous hunger from adding this, which I definitely still notice. I find myself craving different food, before and after adding the HGH. I think this is because before when I just used the incretin peptides I would still get hungry, but just get full a lot quicker. Now, my baseline hunger is a lot lower so bland foods aren't as appetizing as before. Similar to when you're full and only good tasting food is easy to eat. While 8-9mg is stronger I've decided to stay at 6mg as the hunger I feel is not from the stomach. For now, I consider this peptide best for resetting tolerance to the incretin peptides as those are just more enjoyable to use. I've also further reinforced that eating a lot of food does not change how full I feel, so I find myself eating more for taste than to feel full. Setmelanotide doesn't slow gastric emptying so the food I do eat never fills me up. It's somewhat difficult to explain, but essentially it feels like it gets rid of hunger, but does not get rid of cravings.



Regarding side effects, my systolic has normalized to 105-110, but I've added eplerenone with HGH, so it's likely because of that. The stretching and yawning has completely stopped. Reflux is still pretty shit, I've stopped using oral AAS for the time being.

The biggest benefit is something I didn't even realize until now as I'm typing this. I have really bad dry eye from Accutane. I've tried all kinds of eye drops and heating pads with no success. I'm basically squinting all the fucking time, but decided to tough it out as I have just a couple months left. I just realized I haven't squinted in weeks, and sure enough it seems to be the setmelanotide.

Another Pan-agonist

I'm curious to see if this benefit sticks around as the data on pl9643 seems conflicting- perhaps it stops working after some time. I will keep you guys updated on this as well for the small number that are affected.



For further testing I've ordered 10g of Orforglipron raws. Although it may seem to just be an oral semaglutide, it is actually much better, at least on paper. Consider it's shorter half life and that it is not titrated upwards in studies. This is because unlike semaglutide, Orforglipron recruits arrestin almost negligibly, so it is very resistant to receptor desensitization, but it is not immune like setmelanotide. However, because it works to slow gastic emptying I do think it would be a good addition to it by targeting a different form of hunger. It is worth noting that tirzepatide and retatrutide also work to be more selective, but they are not as selective as Orforglipron. I speculate best combo to be Orforglipron, Setmelanotide, and micro dose retatrutide for gip effects. Cagrilinitide is trash, desensitization is way too quick.

It will probably be a few weeks before I receive the raws and can start testing, but I will update at that time once I start using it.
 
I speculate best combo to be Orforglipron, Setmelanotide, and micro dose retatrutide for gip effects. Cagrilinitide is trash, desensitization is way too quick.
Could you elaborate more on why Cagrilinitide is trash? Isn't CagriSema almost out of novo's pipeline?

Also whats Melanotan 2's binding affinity to MC4R? Is MT2 and Setmelanotide comparable in binding affinities?
 
Could you elaborate more on why Cagrilinitide is trash? Isn't CagriSema almost out of novo's pipeline?

Also whats Melanotan 2's binding affinity to MC4R? Is MT2 and Setmelanotide comparable in binding affinities?
It’s just my experience, cagri was potent but stopped working very quickly for me.

They are comparable in affinity for MC4R, but MT2 is roughly 14 times more potent for MC1R and 19 times more for MC5R, so much less selective.
 
It’s just my experience, cagri was potent but stopped working very quickly for me.

They are comparable in affinity for MC4R, but MT2 is roughly 14 times more potent for MC1R and 19 times more for MC5R, so much less selective.
Ah interesting. Have not yet tried Cagri out, will prob use it next cut.

Interesting. I guess isolating the MC4R is the design of the drug.

Palatin Announces MC4R Agonist Bremelanotide Co-Administered with GLP-1/GIP Tirzepatide Meets Primary Endpoint in Phase 2 Obesity Study | Palatin Technologies

The data demonstrated that co-administration was additive and synergistic, resulting in increased weight loss, and that co-administration did not result in increased tolerability or safety issues for patients. The data also showed that low dose MC4R agonist bremelanotide stopped the rapid weight regain seen after ending GLP-1/GIP tirzepatide treatment.”

Seems promising. MT2+Tirz= synergy
 
Ah interesting. Have not yet tried Cagri out, will prob use it next cut.

Interesting. I guess isolating the MC4R is the design of the drug.

Palatin Announces MC4R Agonist Bremelanotide Co-Administered with GLP-1/GIP Tirzepatide Meets Primary Endpoint in Phase 2 Obesity Study | Palatin Technologies

The data demonstrated that co-administration was additive and synergistic, resulting in increased weight loss, and that co-administration did not result in increased tolerability or safety issues for patients. The data also showed that low dose MC4R agonist bremelanotide stopped the rapid weight regain seen after ending GLP-1/GIP tirzepatide treatment.”

Seems promising. MT2+Tirz= synergy
Yes bro, it’s all in my original post. It is all due to the MC4R-Kir7.1 complex. Anything that agonizes MC4R will work. I chose setmelanotide as it is the most selective.

Consider half life’s when choosing too
 
It’s just my experience, cagri was potent but stopped working very quickly for me.

They are comparable in affinity for MC4R, but MT2 is roughly 14 times more potent for MC1R and 19 times more for MC5R, so much less selective.
How long did it take to realize you were getting desensitized from Cagri, and at what dose did you decide to stop?
 
Brilliant stuff! I've not seen Setmelanotide on any vendor lists AFAIK, though.

The data also showed that low dose MC4R agonist bremelanotide stopped the rapid weight regain seen after ending GLP-1/GIP tirzepatide treatment.”
I can't imagine taking PT-141 every day. Constant erections.
Also, that stuff doesn't feel like something you should be pinning regularly IME
 

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