While absolutely true, i think F&B was just noting that anything can be dangerous, given a high enough dose.
I heard some false info on the street today. "If you take 2cb everyday, youll develop certain necrosis"
Afaik totally false, tho i do not recommend taking any substance every day. It was brought up in regard to a friend i have, he takes it almost every day, but almost in a microdose style. Generally 5-10mg
Yes, pretty much totally false, unless you're extremely sensitive to the vasoconstrictive effects of partial 5-HT2a agonists, and don't take an alpha blocker to cope
Now I wouldn't call 5 to 10 mg of 2cb microdosing considering 10 mg is an actual good trippy dose for a lot of people. Microdosing 2-CB would be 500 micrograms to a milligram.
What would probably start to cause issues with circulation and possibly necrosis, (if you didn't die) would be daily use of things like bromo-dragonfly, many of the NBOMe family, DOB; any of the psychedelic substituted (halogenated) phenyethylamines THAT ACT AS FULL AGONISTS AT THE 5-HT2A receptor especially those I specifically mentioned have resulted in fatal peripheral vasoconstriction.
It's interesting to note that there are 5-HT2A serotonin receptors all throughout your blood vessels, and when agonized they result in severe vasoconstriction. Some of the best hypertensive medications while being either alpha adrenergic or beta adrenergic or a combination are also 5-HT2a antagonists.
Of even more interest is ondansetron (a 5-HT3 antagonist) which is commonly used to combat nausea when taking MDMA, can actually prevent systolic hypotension caused by anesthesia. However, it doesn't seem to cause hypertension.
Tolazoline is an extremely safe alpha adrenergic vasodilator that has been used to rescue people from serious psychedelic vasoconstrictive episodes. However It is an IV drug.
Just to prevent any vascular damage since your friend is continually taking 2-CB (which does raise blood pressure), you may want to talk to your friend about finding a good oral.alpha or alpha-beta blocker that has a low side effect profile and won't dampen the serotonergic effects of 2-CB.