Energy drinks are marketed as a way to boost alertness and enhance mental or physical performance. They provide energy in the form of various stimulants, vitamins and amino acids. Energy drinks are flavored beverages containing caffeine and other energy boosters, These may include B vitamins, taurine, carnitine, herbs and guarana among others. Compared to energy drinks, energy shots provide a higher dose of caffeine and are mostly sold in single-serving shot-sized plastic bottles. Energy drinks are widely sold in cans or bottles at grocery stores and vending machines, as well as convenience stores and even bars.