I don’t smoke (besides a very occasional cigar) but I chewed 4 mg “stop smoking” nicotine gum during my Level II exam (and passed) although it’s worth noting that I also had caffeine in my system. I would not recommend chewing it during studying, as chewing it every day would lead to addiction. It’s worth noting that you really don’t “chew” the gum per se, but chew it briefly and then stash it between your gum and cheek, moving it occasionally. I did feel like this had a positive effect, but for a different reason-nicotine is a stimulant, and in small amounts (like the gum) will enhance cognition, memory, alertness, and focus. However, if you ingest too much nicotine, the effect changes from stimulant to sedative, so don’t go chewing four or five pieces at the same time.