The majority of appetite suppressants are stimulants. They are related to amphetamine or speed. In fact, amphetamines were used by the British during the First World War as appetite suppressants for soldiers. Amphetamines and other stimulants became used by the general population after World War 2. Amphetamine itself was sold as an appetite suppressant until the 1950's when it was banned because of the increasing abuse of it. Amphetamines have many dangerous side effects including increased heart rate and hypertension.

High rates of heart attacks and pulmonary hypertension led to the withdrawal of many stimulant products from the market. An example is Fen-phen, which was withdrawn in the 1997 due to abnormally high incidences of valvular heart disease. Currently it is estimated that there are 50,000 lawsuits pending against the manufacturer of Fen-phen. All stimulants can be dangerous to some degree. Despite these dangers, many stimulants are still used today as appetite suppressants.

Hoodia, on the other hand, is not a stimulant. It is believed to work by stimulating that portion of the brain which measures sugar intake. At present, there are no known side effects to the use of Hoodia. It certainly does not cause the same problems that led to the withdrawal of certain stimulant-based appetite suppressants. It should be noted, however, that Hoodia has not been in recorded use for very long, and not very many formal clinical studies have been done. One should also be careful when taking a Hoodia supplement to ensure that it does not contain a stimulant as well. Some products claim to be Hoodia, and thus safe, when in fact they contain dangerous levels of stimulants. There may be more than just Hoodia in that little pill you are taking.

Many people wish to believe that there is a magical method to lose weight. In truth, the use of an appetite suppressant should be combined with physical activity and a proper diet in order to lose weight successfully and to keep that weight off. Any use of medication for weight loss should only be done after consultation with a physician.