Many books and articles documented the use of stapeliad species as food plants and earlier references refer to the use Hoodia species as a thirst quencher. However, prior to the publication of the patent application, only a single reference referring to the use of Hoodia pilifera as appetite suppressant was found.

– J Ethnopharmacol. 2008 Oct 28;119(3):434-7. Epub 2008 Aug 30. Hoodia gordonii: a natural appetite suppressant.van Heerden FR.

Hoodia’s safety is unknown. Its potential risks, side effects, and interactions with medicines and other supplements have not been studied. The quality of hoodia products varies widely. News reports suggest that some products sold as hoodia do not contain any hoodia.

– http://nccam.nih.gov/health/hoodia/

The results showed that all doses resulted in a decrease of food consumption over an eight day period and a body mass decrease when compared to the control sample receiving only the vehicle. In a comparative study against a fenfluramine control sample, compound 1 resulted in a reduction in food intake over the study period, with a concomitant overall decrease in body weight while fenfluramine resulted in a small decrease in food intake, but an increase in body weight (though less than control group) over the same period of time.

– Phytochemistry. 2007 Oct;68(20):2545-53. Epub 2007 Jul 2.
An appetite suppressant from Hoodia species.van Heerden FR, Marthinus Horak R, Maharaj VJ, Vleggaar R, Senabe JV, Gunning PJ.

Hoodia gordonii – The limited available information indicates that some of the plants display remarkable regional variation in morphological, genetic and chemical characters that should be more thoroughly investigated. Basic biological information is needed to guide the rapidly accelerating commercialization process, especially the selection of superior clones, the development of new cultivars and the standardization of raw materials.
– J Ethnopharmacol. 2008 Oct 28;119(3):342-55. Epub 2008 Jun 3.
A broad review of commercially important southern African medicinal plants.van Wyk BE.

This study was aimed to predict the pharmacokinetic properties of Hoodia gordonii. A series of in vitro assays was used to predict its gastric, intestinal and metabolic stability, intestinal and blood brain barrier (BBB) transport, protein binding and interaction with major drug metabolising enzymes. The results indicated a possibility of drug-herb/botanical interactions when products containing H. gordonii are used simultaneously with other botanicals/herbs/drugs.

– Characterization of in vitro pharmacokinetic properties of hoodigogenin A from Hoodia gordonii. — Madgula VL, Avula B, Pawar RS, Shukla YJ, Khan IA, Walker LA, Khan SI. — Planta Med. 2010 Jan;76(1):62-9. Epub 2009 Jul 28.