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Hoodia gordonii:

The cure for obesity or just another hoax?


By Liz Paddack

Date:  10/14/2006




What is Hoodia gordonii?

Hoodia gordonii is a plant found in Kalahari Desert of South Africa. It is reported to be an appetite suppressant as well as an energy giver.  Its appearance is spiny which is why it is often mistaken for a cactus. However, Hoodia is not related to the cactus but is a member of the milkweed family. 

        Hoodia gordonii is not a new discovery.  In fact, this plant has been important to tribal groups in South Africa since prehistoric times. The San tribesmen have used Hoodia to suppress appetites, quench thirst, and give energy.  They exploited this plant primarily during times when food was not plentiful and during long hunting trips.  While this plant is not new to the people of Africa, it is a relatively new discovery to the modern world.  Only recently has Hoodia become commercialized.  Despite the short time that it has been on the market, many claims about the powers of this plant have arisen.

How does Hoodia gordonii work?

Hoodia gordonii is marketed as a radically new way to lose weight without feeling hungry. Scientists studying this supplement found a completely unknown molecule now known as P57, and it is this molecule that is the miracle behind the plant.  Dr. Richard Dixey, a doctor at the bio-pharmaceutical company in which the license for P57 was sold, said that P57 works because:

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.


 This means that the molecule actually activates the brain to make a person feel full without having to at any food.

What are the claims about the effectiveness of Hoodia?

        As with any weight loss method, there are numerous claims with very little scientific evidence to support the claims.

Some of the claims include:

·       “It contains enough Hoodia Gordonii extract to act as a powerful appetite suppressant. Making it easier to reduce your caloric and fat intake and lose weight faster!”


·       “Hoodia gordonii is entirely natural. Hoodia gordonii is not a stimulant, and has no known side effects. Hoodia appears to be safe for most people.” (

·       It has been proven to reduce calorific intake by as much as 40%.” (

Most claims about Hoodia gordonii come from personal testimonials which often include before and after pictures.

·       Roger from Albany, New York said “It wasn't for lack of trying, but all my life I was known as the 'Fat Boy'. Truth is, I tried just about every diet pill, including those prescribed by my doctor without losing any real weight.  So naturally, when I heard about this new all-natural "miracle" pill that has no side effects I almost passed on it.  Thank goodness I didn't because look at me now!  I lost over 60 lbs using the Hoodoba™ Hoodia gordonii pills.  (


What evidence supports these claims? Who is presenting these claims?

Testimonials have no way to substantiate their claims so it is necessary that we take them at face value.  Another reason that it is hard to believe claims such as the ones above is because they are from websites that are trying to sell Hoodia products.  The companies want to make as much money as possible so it necessary to state claims and give personal testimonies that support the product that company is trying to sell.  The claims from above support the idea that Hoodia is the new miracle weight loss method which is what companies trying to sell Hoodia want the consumers to believe.

One company selling a Hoodia product, Hoodoba™, shows that their product has been certified by an independent laboratory. The website even shows the laboratory report: (


The report is hard to read and understand.  Nevertheless, many people will see this laboratory report and assume that is supports the claims of the Hoodoba company.  The report might do this but there is always the chance that the report is fabricated.  One reason to believe that this report is false is that the name of the laboratory is never given.  It is always referred to as an independent laboratory. As with any report on a product selling website, it is should only be taken at face value.

Clinical Trials

        Because Hoodia gordonii is new, there are limited numbers of scientific trials that try to comprehend the effect that this plant can have on the body.  I encountered so much difficulty in locating actual clinical trials that I was only able to find one study pertaining to Hoodia gordonii.  In fact, only short term studies have been done.  While searching for clinical trials in Hoodia gordonii, I was unable to find trials that specifically used the plant.  The trials I was able to find isolated the molecule P57 from Hoodia and then ran experiments on it. 

One study by David B. MacLean and Lu-Guang Luo (2004) questioned whether P57 had an effect on the measure of hypothalamic ATP in the body.  It should be noted that ATP is used by the body for energy.  Their study was conducted on male Sprague-Dawley rats which weighed 170±5 grams.  The rats were divided into 4-6 rats per group with 36-72 animals used in the experiment.  The hypothalamus was collected from another group of 17 fetal rats.  The rats from the first group were given injections of P57 and then after a 24 hour period, the hypothalamus from each rat was collected. 

This experiment found that P57 increases hypothalamic ATP by 5-150%.  In one part of the study, P57 was injected into the third ventricle of the rats.  In this situation, ATP was increased by 40-60% and it reduced food intake in the following 24 hour period by 50-60%.  This experiment also found that P57 which is similar to the steroidal core of cardiac glycosides is probably a compound that has a central mechanism of action (MacLean, 2004).


According to the findings from the study above, Hoodia gordonii or its molecule P57 actually increase the hypothalamic ATP.  This means that the energy in the body is increased when Hoodia gordonii is introduced into the body.  The increase in energy could be one possible cause of appetite suppression in individuals.  While the evidence from MacLean’s study supports the idea that Hoodia gordonii is an appetite suppressant, I still have reservations with the claims made by companies selling this product.  One hesitation I have is that I only found a study where rats were the subjects.  For me to believe in the power of Hoodia, I would need to see clinical trials with humans as the subjects.  Another reservation I have is that I think Hoodia could actually be an appetite suppressant but probably not to the degree that some of the personal testimonials claim.  I feel that testimonials are often sensationalized.

I must say that despite my reservation and skepticism, I would probably like to try Hoodia gordonii.  I am not easily persuaded by advertisements, but Hoodia did grab my attention.  I think it would be interesting and worth trying to see if Hoodia gordonii actually works.


MacLean, D.B., & Luo, L.G. (2004). Increased ATP content/production in the hypothalamus may be a signal for energy-sensing of satiety: Studies of the anorectic mechanism of a plant steroidal glycoside.

Brain Research, 1020, 1-11.



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