Here are some of the most common energy drink ingredients, and where they rate on usefulness and safety. I covered energy drinks this before, but this offers more detail.
Ginseng is used most commonly in Chinese medicine. Ginseng is an herb that has been used traditionally to treat numerous ailments. It is generally thought to boost immunity and improve overall health. Research does not conclusively back up these claims, but short-term use is thought to be safe.
Taurine is an amino acid found in protein, meat, fish, and breast milk. It helps us maintain neurological function and regulate fluid levels. There are some claims that taking a taurine supplement can improve athletic performance, but not much data exists on its efficacy or its safety as either a supplement or energy drink ingredient.
Guarana is an herb that is often used as a stimulant in teas, either added or naturally occurring. Its major component is caffeine. It has been associated with increased energy and enhancement of physical performance.
Ginko biloba is another herb, added to supposedly increase alertness. It has been used medicinally for thousands of years, according to the Mayo Clinic, and research supports its use for some medical conditions including dementia, anxiety, and schizophrenia. For other uses, evidence is lacking or mixed.
Carnitine is naturally produced by our bodies and is a substance that is used to turn fat into energy. You can also buy it as a supplement, and it claims to boost exercise performance.
Some studies suggest carnitine may be promising in treating various health problems, like certain heart conditions, kidney disease, and hyperthyroidism, but in all cases, more research needs to be done.