2 replies to this topic

[Furniture]

It seems that this topic died down a long time ago. I haven't seen a thread about KOR antagonists on this forum for many years...but I'm wondering if anyone in 2026 knows of a legitimate vendor or other source that offers a selective KOR (Kappa Opioid Receptor) antagonist?

 

Basically, I'm talking about either JDTic, Norbinaltorphimine (nor-BNI) or Aticaprant.

 

There have been lots of other KOR antagonists thrown around on this forum but most of these aren't what I'm looking for. For example Amentoflavone's action on KOR is weak and others (like Buprenorphine & Naltrexone) aren't selective for KOR and are actually much more active at the MOR, which is an undesirable effect for what I'm looking for.

 

However, if you know of another KOR antagonist (apart from the 3 I mentioned) that is selective and strong-acting... feel free to mention it. 

 

I do know of pglchem as a source for nor-BNI. However, that's the only one I've found and I'd like to explore alternate options if they are ones. As of yet, I do not know of a vendor that offers JDTic or Aticaprant. 

 

Feel free to send me a DM if you'd rather communicate that way. 

 

 

[Galaxyshock]

What is your goal with kappa-antagonists, decrease in fear/anxiety responses or dysphoria? I'm kinda interested in kappa-antagonists too. I've used Naltrexone, Apigenin and Ginseng which show some kappa-antagonist activity but of course aren't particularly strong or selective but I've still benefited from them.

 

I would be careful with strong antagonists though, the kappa-opioid receptor isn't there just to do harm as the endogenous ligand dynorphin is 10 times stronger analgesic than morphine.

[Furniture]

What is your goal with kappa-antagonists, decrease in fear/anxiety responses or dysphoria? I'm kinda interested in kappa-antagonists too. I've used Naltrexone, Apigenin and Ginseng which show some kappa-antagonist activity but of course aren't particularly strong or selective but I've still benefited from them.

 

I would be careful with strong antagonists though, the kappa-opioid receptor isn't there just to do harm as the endogenous ligand dynorphin is 10 times stronger analgesic than morphine.

 

Goal would be a decrease in anhedonia. 

I wound up testing nor-BNI (aka Norbinaltorphimine) in the time since I posted this. I ended up just going with Pglchem. I couldn't find any additional vendors offering nor-BNI (or any vendors at all offering JDTic or Aticaprant). They're a chemical supplier based in Ukraine (https://pglchem.com/...inaltorphimine/) and they provide mass-spec & proton NMR data for it (on this page --> https://pglchem.com/...naltorphimine), so I felt somewhat comfortable purchasing it from them. I did not have it third-party tested. 

I only trialed a single 200mcg dose and the effect was the opposite of what I expected. That single dose was enough to produce a mild to moderate dysphoria. And this lasted for several days, give or take. I observed no other effects, positive or negative, apart from the dysphoria. No changes in pain, cognition, wakefulness, etc. 

I can't say for certain why this happened. A "nocebo" effect could explain it, considering the single small dose. It could also be that blocking KOR just isn't compatible with my specific neurobiology. 

However, I do have to say that the dysphoric sensation felt almost identical to my past experiences with Naltrexone. Perhaps the nor-BNI that I received from pglchem was not authentic or was not pure. Maybe it contained Naltrexone or some other related analogue with MOR-blocking effects (which would explain the dysphoria). For what it's worth, nor-BNI is very structurally similar to Naltrexone, so maybe something went wrong during synthesis? I don't know...

I do plan on trialing it again in the future, just to confirm how it affects me. But because of the possibility of multiple day dysphoria following administration, I'll need to plan accordingly. The last time it had a negative impact on my work performance.