It is not entirely inactive (I'm the one who reported minimal effects after 10mg oral and 5mg insuffated). My 4-ho-NMT required the addition of acid to make it soluble in water for injection, did your friend do this?
4-ho-NMT may be much more influential in combination with psilocin than it is alone. Manic energy and idiomotor effects were pronounced when I combined the two. Over the weekend I did psilocin alone (4mg IM, 6mg oral, 4mg insufflated over an hour) and found it to be much smoother and relaxing than the first time, even though I expected that the 4-ho-NMT had little to no influence on it. After the oral dose plateaued I IM'd 5mg of 4-ho-NMT to see what influence it would have, if any. After 10 minutes nothing had changed and I started to think my first experience was a fluke. The whole time I was waiting for the 4-ho-NMT to come on I was sitting down. Upon getting up and walking I began to feel compulsions to contort my arms, legs, and neck in strange jerking or rolling motions just like last time. The manic energy and idiomotor movement was not as pronouced as it was with 10mg oral and 5mgs insufflated 4-ho-NMT with just 8mg psilocin insufflated (at once, over an hour after the 4-ho-NMT), suggesting that the 4-ho-NMT requires psilocin to produce the effect, but is itself responsible for the brunt of it. (I'll also mention that during the first experience there was a reflexive swallowing effect whose speed and irresistibility was directly proportional to the coldness of the liquid I drank.) This continued for the next two or so hours, but would stop when I sat back down to watch a DVD. I don't think it was a placebo effect because the spastic movements (which were accompanied by an extremely giddy sensation) would occur even when I was immersed in thought with no expectation of the movements occurring, so long as I was already in motion. I'm interested to know if anyone else tried the combo and each alone, and noticed similar effects. I've only done this twice and it's possible that the second time the idiomotor effects of the psilocin were simply delayed and just happened to coincide with the injection of 4-ho-NMT, or that the phenomenon is entirely idiosyncratic.