Hoodia is a cactus that's causing a stir for its ability to suppress appetite and promote weight loss. 60 Minutes, ABC, and the BBC have all done stories on the hoodia gordonii weight loss pill. Hoodia is sold in capsule, liquid, or tea form in health food stores and on the Internet.
There isn't much published research on hoodia. Researchers at Brown University in Rhode Island recently found that the steroidal glycosides in hoodia affects nerve cells in the hypothalamus that monitor blood glucose. Simply put, the brain is tricked into thinking there is enough energy (blood sugar) and doesn't need to eat, so it shuts down the hunger mechanism.
In animal studies, hoodia is believed to reduce caloric intake by 30 to 50 percent. There is one human study showing a reduced intake of about 1000 calories per day. However, I haven't been able to find either study to actually read for myself and am going on secondhand reports.