Caffeine is of course a major component of every day drinks such as tea and coffee and is also included in Estrin-D. It is claimed that over 70% of the American population take more than 300 milligrams daily. As well as in familiar drinks it is used in energy drinks such as Red Bull as well as in many over the counter analgesics and other medication. Medically it is a as trimethylxanthine, useful as a heart stimulant and it also works as a mild diuretic. It works in the same way as certain drugs, the amphetamines, cocaine, and heroin, all of which work on the action of the brain although in a milder way, and like them it is addictive.

Ginger Root- Zingiber officinale is the actual plant that grows an underground stem, commonly called ginger root and is a very popular spice, which also has medicinal properties. Main components of the ginger root are a mixture of volatile oils, zingerone, shogaols and gingerols, which have been found to display analgesic, antipyretic, antibacterial and sedative properties. Ginger also contains a fragrant essential oil, essentially consisting of sesquiterpenoids. As a spice, it is an important part of the Indian and Chinese cuisine, in the Western World it is known as the main ingredient in cookies, such as the gingerbread man, but also in the popular beverage ginger ale. Traditionally used as a treatment for nausea, diarrhea, motion sickness, general stomach settler, but also as a cold remedy, just recently properties for treatment of osteoarthritis and diabetes have been discovered.

Green Tea Extract increases energy expenditure and affects fat oxidation, which therefore promotes weight loss by increasing the body's metabolism.

Guarana has in recent times received widespread popularity because of an energy drink. It is actually a climbing plant in the family related to maple and is native to the Amazon region, predominantly in Brazil. It is a flowering plant with big leaves, but the fruit is the most prominent component, not bigger than a coffee bean. Guarana fruit has about the double content of caffeine when compared to the coffee bean. Besides the cognitive and fatigue reducing effects of caffeine, guarana displays also other interesting properties, such as the assistance in a weight loss program; namely, guarana affects the perception of the satiation, making the person feel full sooner. Further antioxidant and antibacterial effects have been noted as well. In combination with linoleic acid, guarana has shown fat cell reduction effects in mice.

Kola Nut, bitter brown seed that contains caffeine. Once used to make cola soft drinks, Kola Nut has been replaced by artificial flavourings in most beverages.

Some Unknown Ingredients, which is a common practice for many supplement manufacturers. They use ineffective common ingredients and trademark their name for them to disguse the actual low quality ingredient contained.

Yerba Matte- The plant of the yerba maté, as yerba matte is actually called, is a small tree or a shrub which can grow up to a size of fifteen meters. The leaves and twigs have traditionally been used to brew a tea like concoction, which is still a very popular social beverage in South America. Yerba maté contains alcaloids that are very similar to caffeine, commonly referred to as xanthines, but also elements like manganese, magnesium and potassium. The main difference between yerba maté and coffee, for instance, is the effect it has on muscle tissue, where it appears to relax smooth muscle tissue, but stimulate heart tissue and that is why it is used in Estrin-D. In other studies, yerba maté was found to work as a monoamine oxidase inhibitor, thereby professing antidepressant qualities.