The hoodia cactus has been shown to reduce appetite in studies with rats. Scientists have show that after the ingestion of hoodia, there was an increase in the chemical atp or adenosine triphosphate. This energy molecule may regulate energy consumption and feeding behavior in rats and people. This may be the mechanism of action for the hoodia cactus.
There are currently studies underway that may prove how hoodia contributes to weight loss once and for all. Most of the studies are being conducted by pharmaceutical companies and are not subject to public review. Aside for the studies in rats, there have been studies humans. These have also shown that hoodia used in the diet of the obese subjects, caused significant reduction in appetite and weight loss.
Pharmaceutical company phytopharm has created an extract of the hoodia cactus containing only the active ingredient involved in weight loss. The subjects taking this compound reduced their own intake of food down to around 1200 calories even though food was available for them. This was a significant reduction compared to subjects recieiving a placebo pill. The group receiving a placebo did not consistently lose weight over the two weeks of studies. The group that received the genuine hoodia extract did lose a significant amount of weight.
There were also some unexpected benefits for the subjects that received the hoodia extract. After the study they had noticeably lower blood sugar and levels of triglycerides.