All energy drinks work no better than caffeinated water. All energy drinks share certain ingredients: caffeine, B12, B6, B3, and Taurine. The only effect-producing ingredient is caffeine, although a B6 boost does help convert phenylalanine into the catecholamines. Here is a histogram showing the top five most common ingredients, ranked by prevalence:

Explanation of ingredient effects

• Caffeine. (See here.)
• B12. B12 does not absorb well when taken orally, so the small amounts placed in most energy drinks will do less than a large amount, which is nothing anyway, unless you have a deficiency.
• B6. B6 is needed for catecholamine synthesis. See here for more.
• B3. None.
• Taurine. None.