The difference between guarana and caffeine is that the former is a type of plant, and the latter is a chemical ingredient. Caffeine is one of the many chemical compounds naturally occurring in guarana plants. This ingredient was first called guaranine on the ingredient labels of products containing guarana. It is often used in energy boosting dietary supplements as an alternative to coffee.
This plant originates in South America and has been in use by Brazilian natives for many centuries for medicinal purposes. It is a climbing vine in the maple family and produces clusters of white flowers and dark fruits, ranging in color from brown to deep red. These fruits contain twice the amount of caffeine naturally that a single coffee bean does.
Guarana and caffeine were originally marketed as two separate and uniquely individual ingredients. Beverages and foods that commonly contain caffeine list this chemical on the ingredient label, such as chocolate, coffee, tea, and soft drinks. Energy and dietary supplements which contained guarana included the chemical ingredient guaranine on the label instead, and manufacturers claimed this as a more natural supplement and alternative method to caffeine for improving metabolic functions. Scientists later discovered that guaranine is the same ingredient as caffeine, and guarana products have since been appropriately labeled.
The effect of guarana and caffeine, its main ingredient, on the body is stimulation to both the nervous and cardiovascular systems of the body. One hour after being ingested, levels of this chemical appear at their highest in the blood stream, and their affects can linger for several hours following. Individuals who have taken caffeine tend to find their heart rate elevated, their blood flow increased, and their metabolic rate improved. This can create an overall feeling of being awake combined with an improved mood and greater attentiveness.
Some foods and beverages containing guarana and caffeine are attributed with weight loss abilities, and are believed to provide an aphrodisiac-like side effect. These claims are generally unsubstantiated and have little to no basis in scientific study. The overall increased metabolic rate of the body after ingesting caffeine can cause it to burn more calories than it would otherwise, and can create the sensation of an enhanced mood state. These are side effects, however, of the chemical's interaction with the heart and cardiovascular system and are not as a result of any hormonal influence on the body by caffeine.