Thats the truth Ive noticed too. I took two 400ug blotters of 25i nBOME one night, then the next night took 5 hits of lsd which was coincidentally the most Ive ever taken. Normally 2 hits of lsd is pretty intense.. These did nothing. They worked, had I had no tolerance I wouldnt been off the walls. A buddy of mine ate 2 that night with no tolerance what so ever and he could hardly talk.. The night before I didn't trip too hard either for some reason... It was a bad setting though that night
One big exception is these fancy new x-NBOMe you kids have nowadays. They are pretty exotic in the way they hammer certain key receptors producing classic psychedelic effects with doses almost as low as LSD with less confusion or "mind fuck" than the classic psychedelics. Because they hit those receptors extraordinarily hard they cause tolerance like no one's seen before. If you take one blotter and decide two hours later to take a second blotter, the tolerance from the first blotter will reduce the effect of the second blotter to almost nothing. Consensus is that you should wait two weeks before taking an NBOMe again.