By far the best natural stimulant i've every tried is derived from some plants, but usually sold in powder form its 'phenylethelamine', perfectly legal and 1gram is needed on empty stomach (as it compets with protiens), with juce or cordial,water etc. Not only does it lift your alertness for two-three hourse but dramatically boosts mood and no after crash like guranna/caffine. Scientists constantly say that it's useless taking it because it's rapidly degraded by Monoamine oxadise B, that it doesnt have time to reach brain.....rubbish maby 100-200mg is useless but a gram works. If you know of an potent plants that have (selective) maoi b inhibition then effects last much longer. Kava is a maoi b inhibitor but very mild and its a sedative to combining the too will put you to sleep rather than wake you up! Mabey someone else knows of plants with selective maoi b inhibition (that siggnificant) passionflower is very very weak at this site.