ISO is similar to 4F-MPH in its method of action. They are reuptake inhibitors. ISO works on both NE and Dopamine. 4F-MPH works just on Dopamine. If you like 4F-MPH, you should like ISO. I'm trying the first time this week.

3-FPM is a releaser, more like amphetamine, but it also releases some feel good serotonin to round things off.

I enjoy 3-FPM more, because it has more of a push for me to do things I'd rather not do. They become more pleasant. But it's draining, and redosing works at 75% efficacy, I feel, and there is a strong urge to redose. If I keep my doses the same(around 80mg or so), by the end of the night, I can usually also because the last redose doesn't do much.

I did not redose often with 4F-MPH, because, like you said, I felt cracked out on it and it was pure mental stimulation. It did make me scattered, but my doses were probably too high. Plus it lacks much euphoria, except at the very beginning, but I'd be all stimmed up, doing stuff I would do when procrastinating for most of the time, and then feel bad about it.

I'm hoping ISO is as advertised: a little push and a little clean stimulation. If anything in looking for something other than 3-FPM that allows me to get stuff done over the weekend without leaving me feeling drained like 4F-MPH, or increasing 3-FPM use.

Next weekend I'm going to try low dose 3-meo-PCP (starting at 2-3mg) for my weekend breaks. should be interesting.

So essentially I love 3-FPM too much, feel 4F-MPH is too draining, and am trying ISO for the first things today. Going to get a nap in and then dose.

I haven't had trouble sleeping on too many of these, though regular benzo use became a thing during my last 3-FPM binge.

Currently tapering with diclazepam, and take maintenance Kratom doses (15g/day).