I was on Seriphos for 4 - 6 weeks - can't remember exactly. The manufacturer says that people shouldn't stay on it longer than three months in total and I wanted to leave some "spare" time for it. I started on 1 pill per day, but went up in dose quite quickly - every two or three days I think it was, I added another pill. I ended up taking 1 in the morning and 2 in the evening, and wasn't prepared to take more than that.
While I was on the Seriphos I felt awful - really awful. I was incredibly tired and headache-y on it. But I persisted for a few weeks. I didn't really appreciate that it had done anything until I stopped taking it, and that realisation that I had improved took a while.
Since I was on it my general jitteriness and anxiety has dropped a bit, and falling asleep is a bit easier than it used to be. My anxiety problems have been going up again recently though, and I intend to do another saliva test when I can afford it, then do another stint on the Seriphos, probably of another 4 - 6 weeks again. I still have roughly half of the capsules left and I want to see what happens if I use them up.
I have read of some people who stay on it for years, and some people who take vast quantities each night - 15 or 16 pills or more, and I find that astonishing!
I won't say that Seriphos was a life-saver or anything like that. But I don't regret taking it.