My sister and myself tried these when we were in amsterdam. The effects hit us about 1hr 30min later, and they hit hard. My sister bugged out and brought me down with her. The full effects lasted for about 16hrs. Then there was an even worse part, The Down. We were sick as hell for about 5 days, also we both suffered from depression because it was raining just about every day, and being sick at the same time did not help. I will have to admit, in all, this was the worse experience I have ever had.