1. Eleutherococcus tincture - 30 rubles at any pharmacy, enough for 4 sessions (on average). Adopt, in accordance with the instructions.
2. Ginseng in granules (the price is also about 30 rubles). 5 pieces in your mouth if you have to be awake for three hours, 10 pieces enough for 5 hours, 15 to 20 - that the brain "after yesterday's" launched.
3. Green tea + 1 slice of lemon + 1 teaspoon of honey. Good invigorates. Lasts for 2 hours. At the same time relieves tension. Very good help before exams, important interviews, etc.