Tired / can’t focus

100–200mg caffeine (coffee, pill) + 100–200mg L-theanine to smooth the edges. Or: 100mg modafinil. Or: 20mg Vyvanse/Elvanse (lisdexamfetamine) or 5-10mg dextroamphetamine.

Doses listed are typical ranges for healthy adults. Your mileage may vary. When in doubt, ask a pharmacist or doctor. For anything marked “prescription,” you need one — don’t skip that step.