Most over-the-counter diet pills contain phenylpropanolamine (PPA) and caffeine. PPA, is a central nervous system stimulant, and supposedly one of its effects is to depress the body’s desire to eat. So even if you are hungry, your brain doesn’t register it. You lose your appetite.
Caffeine, also a stimulant, is typically used to keep us alert and fight fatigue. But it also has the ability to suppress the appetite.
Recently, however, people have been questioning whether or not PPA-based diet pills actually work. Though the drug does depress the appetite, the effects are very small.
PPA-based bills can also be downright dangerous. Its side effects include high blood pressure, nausea, restlessness, anxiety, insomnia, irritability, and hallucinations. The caffeine in the pills can also affect the circulatory function, as well as blood pressure.
The combination of side-effects of PPA and caffeine can be lethal to those who have heart conditions or hypertension. And since both conditions are linked to people who are overweight, taking diet pills could be the equivalent of throwing a lit match into a pool of gas.
There was a time when many diet pills contained ephedrine. A bronchodilator and decongestant, ephedrine was typically used to relieve nasal congestion caused by conditions, e.g., hay fever, or from bacterial or viral infection of the upper respiratory tract. However, variations of this drug were later marketed as natural dieting aids and bodybuilding supplements. It even became a recreational drug, and was marketed as herbal ecstasy. But after a number of deaths, the Food and Drug Administration banned sales of dietary supplements containing ephedra because of illnesses and deaths associated with it. Consider it a cautionary tale.