Hoodia gordonii is a "succulent" plant (like an aloe, similar to a cactus) that is found in the Kalahari Desert of South Africa. The spiny stalks of the plant, about the size of large cucumbers, are covered in spikes that need to be peeled.

The San Bushmen of the Kalahari had been eating the slightly bitter-tasting, fleshy insides of the hoodia for centuries to stave off hunger during long hunting trips in the desert.

In the 1990s, the South African national laboratory isolated a previously unknown molecule in hoodia which appeared to fool the brain into thinking it was full, thereby curbing the appteite. They ultimately named the appetite-suppressing molecule p57 and patented it.

In 1997, the South African Council for Scientific and Industrial Research issued an exclusive license to further develop and commercialize the hoodia molecule to a British biopharmaceutical company, Phytopharm.

Phytopharm's Dr. Richard Dixey, in a BBC interview, explained how p57 works as follows:

"There is a part of your brain, the hypothalamus. Within that mid-brain there are nerve cells that sense glucose sugar. When you eat, blood sugar goes up because of the food, these cells start firing and now you are full. What the hoodia seems to contain is a molecule that is about 10,000 times as active as glucose. It goes to the mid-brain and actually makes those nerve cells fire as if you were full. But you have not eaten. Nor do you want to."

In 1998, Phytopharm sublicensed the rights to develop and commercialize hoodia to the pharmaceutical company Pfizer, and a phase I clinical trial was initiated in October 1998.

While early-stage clinical trials were encouraging, Pfizer ultimately concluded that it was not possible to make it p57 synthetically in large quantities at a reasonable price. In 2003, Pfizer announced it was returning the rights to p57 to Phytopharm.

In December 2004, Phytopharm announced it had granted an exclusive global license to develop and commercialize p57 to Unilever plc, a global consumer products company that among other things owns the Slimfast brand.

Unilever said the first hoodia products would “probably reach the market in three years” (2007), and might be sold under the SlimFast brand or be included in other Unilever brands.

So that leads to the obvious question: What's the story on the many hoodia products already being touted and sold in health food stores and over the internet?

Well, lawyers say a naturally occurring molecule cannot be patented even if the patent applicant was the first to discover the existence of the molecule. On the other hand, a purified, isolated or altered form of a naturally occurring molecule may be patented.

This appears to mean that while Phytopharm and Unilever can exclusively use methods to extract p57 from hoodia or make hoodia pills, others can make a powder out of the whole hoodia plant, or use a process involving alcohol to concentrate it.

These and other similar processes, however, are likely to produce hoodia products of widely varying strengths and potencies. Quality control is a major issue. Furthermore, real Hoodia is very difficult to obtain. Hoodia Gordonii is, in fact, on South Africa's list of endangered plants. Many of the Hoodia products currently being sold have been found to contain little, if any, of the active ingredient needed to suppress hunger.

Bottom line? P57 may be a promising approach to weight-loss, but it will be a couple more years until Phytopharm and Unilever release the real hoodia pills. Current products are, at best, highly suspect.