Stephen Holt MD and TV. Taylor MD

Hoodia gordonii is a succulent plant from South Africa that has non-stimulant, appetite suppressant properties. It has been used as a dietary supplement or as a source of extracted steroidal glycosides, in drug development experiments. Dietary supplements containing Hoodia alone or in combination with other natural substances for weight control have been sold by many companies under at least 100 different brand names over the past couple of years or so. There has been considerable controversy and confusion about the evidence base that exists to use dehydrated, powdered Hoodia in dietary supplements as an effective adjunct for weight control. This short article attempts to sort science from speculation on the subject of Hoodia gordonii. This stinky plant from South Africa may be the most important ethnobotanical discovery of the 20th century.

Is Hoodia gordonii a Legal Dietary Supplement in the US?

Uncertainty exists concerning the need for Hoodia gordonii to be approved as a new dietary ingredient. Hoodia gordonii has a history of use in the food chain of South African inhabitants over a documented period of centuries. The Dietary Supplement Health and Education Act of 1994 (DSHEA) permits the “grandfathering” of dietary supplements, if they have been in the food chain prior to enactment of this legislation. I have expressed the opinion in my writings and at several scientific or trade meetings that Hoodia gordonii must be considered to be a “grandfathered” ingredient, but there is a grey area, at law, concerning whether or not DSHEA (1994) requires that the dietary substance be in the US food chain, exclusively.

All new, dietary supplement, ingredient filings on Hoodia gordonii have been refused, in recent times, by the Food and Drug Administration on poorly defined, safety grounds. These denials have failed to acknowledge the long standing precedent for the safety of Hoodia consumption in South Africa, where this plant is an government accepted health food. Furthermore, there are descriptions of the use of Hoodia prior to 1994 in the US, at least in the form of tinctures that have been used for hemorrhoid treatment (Ref). North American inhabitants are not strangers to the use of edible succulent plant or cacti in their diet. On balance, a compelling argument exists that Hoodia gordonii must be considered to be allowable under DSHEA (1994), but this debate continues.

Misbranded or Adulterated Hoodia?

It is unfortunate that some brands of Hoodia carry illegal treatment claims for obesity and even more troublesome that many products labeled as Hoodia contain material that is not South African origin, where the health precedents exist for the use of Hoodia as an appetite suppressant. Some products labeled as Hoodia are known to have been adulterated. However, some propaganda on the internet may have to be ignored when it comes to self-serving comparisons of Hoodia products made by marketing organizations that masquerade as information services.

The industry must be fully aware that adulteration or failure to use correct bulk Hoodia powder make some Hoodia supplements into misbranded drugs, at law. Traditionally, retailers of dietary supplements have always considered that it is the obligation of the manufacturers and sellers of dietary supplements to comply with regulatory guidelines, but retailers should share in this duty of care for consumers.

Analyzing Hoodia for Integrity

My colleagues and I have analyzed many samples of material labeled as Hoodia gordonii or sold a bulk reagent and called Hoodia gordonii. In brief, it has become clear that Hoodia imported from Mexico, China and Eastern Europe is not Hoodia gordonii. This material does not contain significant amounts of steroidal glycosides which are believed to be the active constituents of Hoodia that suppress appetite, promote libido and suppress acid secretion.

The methodology used to check the purity, quality and consistency of Hoodia gordonii has been the subject of debate. In brief, there are four ways of analyzing Hoodia gordonii for fidelity. These techniques involve general nutritional analysis (non-specific), light microscopy (semi-specific), infrared spectroscopic analysis and chemical analysis, using chromatographic techniques, to determine the quantitative measure of steroidal glycoside compounds and related chemical analogues.

Many findings are at variance with statements by pharmaceutical companies who claim that there are negligible amounts of active molecules in all Hoodia supplements. That said, there are a large number of Hoodia supplements that do not contain any active constituents, due to purveyance of fake product.

Potential for Patent Wars

There is a body of scientific evidence that Hoodia gordonii and related species of succulent plants may act as powerful appetite suppressants, in a safe manner without acting as cardiovascular stimulant. Unfortunately, much of these scientific data on Hoodia have not been disclosed because extracts of Hoodia gordonii are subject to drug development pathways and proprietary, food-additive, research programs.

The most significant patents held by fortune 500 companies have been licensed from the CSIR, a quasi-government research agency in South Africa. These patents refer specifically to the use of steroidal glycosides or chemical analogues derived from Hoodia. These patents also cover molecules that can be synthesized to have chemical similarity to naturally occurring compounds found in Hoodia.

There are a couple of patent filings in the dietary supplement industry that relate to the use of Hoodia in combination with other natural substances that may be valuable in the management of obesity or the metabolic Syndrome X. At least one of these patent filings is the subject of potential infringement by several manufacturers of combination Hoodia supplements.

Scientific Proof Supporting Hoodia for Weight Loss

Elegant experiments in rats and mice, of both lean and fat body status, with or without genetic tendencies to develop body chemistry similar to that found in the metabolic Syndrome X, have shown consistent weight loss as a consequence of Hoodia administration in their diet, in a free-feeding environment. Such experiments have been performed with whole Hoodia plant and steroidal glycosides extracts with reported consistent reductions in body weight, without any signs of toxicity.

There have been limited human studies in obese volunteers, using steroidal glycoside extracts of Hoodia. These experiments show dramatic, voluntary reductions in calorie intake by an average of approximately 1000 calories per day. These data have not been published in detail, perhaps has a result of them being part of a pharmaceutical development program, but they have been addressed in the media. Figure 3 is a schematic representation of these studies that were performed by Phytopharm PLC (Oxford, England). These studies were placebo controlled experiments in free-feeding humans who were resident in a metabolic assessment unit for several weeks. The conditions and construction of these experiments cannot be used as direct support to claim effectiveness of the use of Hoodia a dietary supplement.

Early Research Experiences with Hoodia Supplements for Weight Loss

There are thousands of testimonials provided on the value of Hoodia gordonii for weight control that have been communicated in the dietary supplement industry or on the world wide web. Testimonials cannot be used as concrete evidence to support an indication for supplements use, even though such testimonials cannot be ignored or are used in direct marketing contexts. Many individuals in the dietary supplement industry have not accepted that testimonial evidence cannot be considered scientific proof. There have been two recent studies on the use of powdered Hoodia gordonii (capsules) as an adjunct to weight loss in overweight humans, in open label, clinical observations. These studies have used the same source of Hoodia gordonii from South Africa.

In the first open-label study, performed in Houston, Texas, twenty individuals who were overweight or obese by conventional definitions received 400mg of Hoodia gordonii powder twice daily in vegetable capsules. The average weight loss among this group was approximately 5 pounds over a period of one month; and there was a high degree of patient acceptance of the supplement, but predictable lack of compliance in some individuals for no substantial reasons. None of the individuals in this study experienced any side effects.

In a separate study seven individuals received Hoodia gordonii in a dose of 500mg twice daily with evidence of modest weight loss and no side effects. This small study has been used to promote a specific brand of Hoodia in the market, but the conclusions of this study that Hoodia can be used to “treat obesity” are unjustified, for several reasons. Treatment claims are not permitted at law (DSHEA, 1994).


Hoodia will remain embroiled in some degree of controversy for a while. Early scientific studies imply a great future for the use of Hoodia gordonii as a dietary adjunct to be combined with a lifestyle change and calorie controlled diet for weight control. The possibility of controlling appetite, in the apparently passive manner observed with Hoodia, may fulfill the key initiative of impacting the global epidemic of obesity by controlling calorie intake.

In contrast to potentially dangerous stimulant drugs or supplements that have been used for weight control, Hoodia has a long precedent of safety of use. Controlling obesity and overweight status has emerged as one of the most important health initiatives facing industrialized societies, as obesity rapidly becomes the number one preventable cause of premature disability and death.

Hoodia gordonii seems to have a special role in the management of the metabolic Syndrome X which affects 70 million Americans and accounts for the lion’s share of all supplement purchases by healthcare consumers in the US. These matters of fact reinforce my assertions of the potential importance of Hoodia gordonii in controlling the global pandemic of obesity. Further scientific research on Hoodia g

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