Guarana seed- General caffeine source.
Ephedrine - A stimulant that works on the central nervous system, concerns about its effects on the heart.
Taurine - A natural amino acid produced by the body that helps regulate heart beat and muscle contractions. Many health experts aren't sure what effect it has as a drink additive.
B-vitamins - A group of vitamins that can convert sugar to energy and improve muscle tone, improve alertness.
Inositol - A member of the vitamin B complex (not a vitamin itself, because the human body can synthesize it) that helps relay messages within cells in the body.

Carnitine - An amino acid that plays a role in fatty acid metabolism.
Creatine - An organic acid that helps supply energy for muscle contractions.
Ginseng - A root believed by some to have several medicinal properties, including reducing stress and boosting energy levels.
Ginkgo biloba - Made from the seeds of the ginkgo biloba tree, thought to enhance memory.