With energy drinks pedaling promises of equipping you with “the mental and physical energy you need” to conquer the day’s challenges, or allowing you to “unleash the beast within” when the going gets rough, you hope the drinks’ contents have just as much bite as the words on their labels.

And with ingredients like caffeine, B-group vitamins, amino acids, carbohydrates and trendy herbs, energy drinks sound like they have the right kick. We’ve popped the tab to take a look inside at the active ingredients inside popular power drinks.

These peppy ingredients are star performers on the ingredients labels of many of the leading energy drinks; we decided to dig in and decipher these energy boosters for you:

Caffeine

The drink’s prized possession is the caffeine, of course, which targets the central nervous system (CNS) and improves reaction speed and concentration by enhancing alertness, focus, and clear-headedness. On top of caffeine’s effects on the CNS, caffeine also increases the release of fatty acids into the blood, leading to increased muscle fat oxidation and decreased carbohydrate oxidation, saving muscle glycogen for later use.

Echinacea Extract

If you’re going to pop any herbs in your all-natural energy-boosting concoction, you better slide in some echinacea extract; echinacea stimulates the immune system, fights off bacterial and viral infections and is often used to aid in the healing of cuts and scrapes. While many energy drinks have infused their tonics with the essence of this popular flower, energy drink guzzlers probably don’t have “boosted immune systems” at the top of their must-have lists.

Gingko Biloba

Finding its roots in the oldest living tree on Earth, gingko biloba is a mental stimulant that is said to help improve short-term memory, enhance concentration and rev up your alertness. And along with acting as an herbal version of the fountain of youth, ginko biloba is also said to improve blood circulation through the body and brain, and to ignite your sexual desire, arousal and orgasmic function.

Glucuronolactone

Helping energy drink guzzlers with memory retention and concentration, glucuronolactone also behaves as an antidepressant and stimulant. This naturally occurring carbohydrate is involved in the body’s detoxification processes at it helps in the elimination of waste substances.

Guarana Extract

One of a handful of natural extracts found in many energy drinks, guarana extract is a creeping shrub native to the Amazon that is often used as a general tonic for the body and is said to provide energy. Guaranine, the active component in the plant, acts on the central nervous system to prevent fatigue and also has tonifying and astringent properties. Closely related to caffeine, guaranine helps to fight the feelings of tiredness while stimulating your metabolism; but unlike caffeine, which stimulates and dies quickly, this component provides a longer sensation of alertness.

Panax Ginseng Extract

Panax ginseng extract (just plain ginseng) is an adaptogen, meaning this herb helps the body adapt and cope with the effects of physical and environmental stress. Enhanced endurance can also arrive at the heels of ginseng, along with reduced fatigue, improved coordination and reaction time and a potentially boosted immune function.

If you’re sleep-deprived, feeling the tolls of rigorous athletic training or attempting to get through long hours at work, ginseng could help you resist stress and improve your mental and physical performance. When put to the test in laboratory studies, ginseng showed “potential in protecting liver and heart health, regulating the function of reproductive hormones, normalizing cholesterol and blood sugar levels, and improving memory and learning.”

Sugar

This tasty additive goes by many names: dextrose, fructose, sucrose, glucose… Whatever the guise, sugars are the simplest form of energy to be broken down and used as fuel for the body’s metabolic functions.

Taurine

The amino acid taurine, which is naturally occurring in the human body, is a key ingredient of bile, which is needed for fat digestion and the absorption of fat-soluble vitamins, as well as helping to regulate and maintain cell membrane integrity. Taurine also aids in thermo-regulation, adjusting your body temperature so you become neither too hot nor too cold.

Vitamins

Niacin, vitamin B6 and vitamin B12, all play a valuable role in energy metabolism — the build-up and break-down of carbohydrates, fat and protein.