Hoodia gordonii is a small plant that is used as a famine food (to suppress appetite and thirst, to make suffering a famine a bit more bearable) and due to that is sought after for possible appetite suppressive effects. The first introduction of Hoodia to the first world (Europe and North America) was based on preliminary studies associated with the company producing Hoodia, and the lone independent study on Hoodia has noted that active dose recommended for a supplement not only failed to reduce appetite but was also associated with some mild and irregular toxic effects that need to be further investigated.
This plant appears to be a source of a large amount (well over 30) steroidal glycosides, and only one is said to be the activ ingredient (P57) yet most of the steroidal glycosides have no research on them. Due to this, the possible toxic effects in humans (confirmed in mice), and both the inefficacy on reducing appetite while having no other apparent marketable effects Hoodia gordonii does not appear to hold any promise for a dietary supplement.