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Brett Sklaw


Cytodyne ORIGINAL Xenadrine RFA, 120 Capsules SK40



What is Xenadrine-RFA-1? What are its ingredients? How does it work?

                The prevalence of obesity is increasing at a dramatic rate today throughout the world.  In fact, approximately 61% of adults in America are considered overweight and 26% are considered obese.  This has happened largely because of the poor dietary habits and sedentary lifestyle of many people in this country.  The result of this has been the creation of numerous weight loss drugs and dietary supplements to try to combat the obesity epidemic.  One such product that has been created is Xenadrine-RFA-1.

          Xenadrine-RFA-1 is one of the many available dietary supplements on the market.  It is a product of Cytodyne Technologies, the producer of several dietary supplements for weight loss and muscle enhancement.  Xenadrine-RFA-1 is an ephedrine and caffeine containing substance that works through a thermogenic mechanism to aid in weight loss.  

A bottle of Xenadrine-RFA-1 contains 120 pills, which is equivalent to one month’s worth of dosage.  Xendadrine contains Citrus Aurantium, MaHuang(source of ephedrine), Guarana Extract(source of caffeine), White Willow Bark(source of aspirin), Acetyl L-Carnitine, L-Tyrosine, Ginger Root, and Vitamin B5.  The active weight loss functioning ingredients are ephedrine and caffeine, with aid from aspirin.      Xenadrine is reported to cause dramatic weight loss, suppress appetite, preserve lean muscle mass, and increase energy level. (


Xenadrine is said to work through a thermogenic mechanism.  Thermogenesis is a process in which the body’s temperature is raised, which in effect causes more calories to be burned because of excess bodily heat.   The body contains three internal heat regulators: thyroid hormones, adrenergic hormones(epinephrine and norepinepherine), and the prostaglandin hormones. Xenadrine-RFA-1 and other weight loss supplements containing the ephedrine/caffeine combination are said to copy the effects of adrenergic hormones.  Adrenergic hormones are important in the mobilization of fatty acids from storage and enable the use of them for energy, instead of stored glycogen or sugar. As a result, more heat is released through the burning of the fats(9 cal/g as opposed to 4 cal/g) and weight loss occurs at a reported dramatic rate because fat stores are drained. (  Ephedrine is said to have an effect on the cellular mechanisms that release fat from fat cells.  Caffeine is said to stimulate fat burning through thermogenesis.  It also is the ingredient said to be responsible for mental alertness and energy level.  Cytodyne reports that Aspirin raises the body’s internal thermostat, so that with the increased production of heat from fat burning, the body doesn’t produce an immune response.  The other ingredients are said to boost the effectiveness of the three main ingredients.   




What claims are made by advertisers?


  • Xenadrine is not only the most popular weight-loss product currently available, it is also the most effective.



  • “Incredible fast weight loss.”  “Visible Muscle Tone.”  “Improvements within one week.”  “Xenedrine burns fat so fast, it has suddenly become the best-selling diet supplement in America.”



  • Xenadrine’s phenomenal fat-burning, muscle-sparing benefits can help you lose body-fat, increase your strength and energy, and produce visible improvements in muscle tone within just weeks of use. As a result you not longer have to ask yourself, ‘How can I possibly lose this weight?’  The question now is- how much weight do you want to lose? And when do you want to lose it?”



        These are just some of the many claims made about the amazing results from using Xenadrine.  What is important to realize is that these claims are made by advertisers who are seeking to sell a product.  They obviously are not going to tell the public about cases in which Xenadrine did not work or even caused some harm.  They present a clear bias in effect.  What is also important to realize is that while Xenadrine does work for some people, it does not work for all people. Therefore, it should not be concluded that Xenadrine is a universal cure all for losing weight.  Websites and advertisements will show people who they claim lost dramatic amounts of weight after using their product.  What is important to realize is that there is no way of knowing whether or not the product was the actual cause of weight loss and if the people even used the product. In addition, the public has no idea concerning the diet and exercise habits of those portrayed.


The companies seeking to sell their products do cite clinical trials concerning the efficacy of Xenadrine.  However, they only mention trials which Cytodyne sponsored and so again a source of bias exists.  What do we take away from the advertisements? Be critical and thoroughly research a product you are going to buy!  Here are some examples for evidence used to support Xenadrine:


-         A double-blind study conducted by a leading clinical testing laboratory reported Xenadrine caused “17 times greater reduction in body fat percentage than an identical group of subjects who used a placebo.”(


-     In a study performed at Eastern Michigan University on the effectiveness of Xenadrine on 20 obese individuals it was   found that “The Xenadrine test subjects lost 524% more total fat and 759% more weight than the placebo group.”




The Real Deal: What do published scientific studies show about the effectiveness of Xenadrine? Are there any adverse effects?


                In an attempt to investigate the efficacy and safety of a caffeine and ephedrine mixture on adolescents Molnar et al(2000) showed support for the weight loss causing capacity of the supplement.  Testing 32 adolescents, divided into a double blind placebo control study the researchers showed a decrease in body weight of approximately 14.4kg, a decrease in BMI of approximately 2.9 kg/m2 and a decrease in body fat of about 6.6 kg when comparing the treatment group to the control.  In addition, they observed no significant difference in adverse events between the groups. 


Boozer et al (2002) discussed the efficacy and safety of herbal ephedra and caffeine for weight loss in a 6 month randomized double blind placebo trial.  Their results showed that there was a difference in decrease in body weight in comparing the treatment group to the control group (-5.3kg treatment vs. -2.6kg placebo).  In addition, a greater decrease in body fat was observed in the treatment group.  The treatment group, however, did show an increase in adverse effects including small changes in blood pressure, increased heart rate, and increased dry mouth.  However, there was no difference between the groups concerning irritability, nausea, chest pain, and palpitations. 


     In a review of several clinical studies, Shekelle et al (2003) addressed questions regarding the efficacy of herbal ephedra and ephedrine for weight loss and athletic performance, as well as addressing safety concerns dealing with ephedra.  The researchers identified 52 controlled clinical trials, of which 46 dealt specifically with ephedrine’s effect on weight loss.  The results show that a combination of ephedrine and caffeine only results in modest weight loss of approximately 2 lbs/month greater compared to a placebo group.  It is important to note that the results published were plagued by methodological problems and therefore to some extent should not be considered valid.  In addition, the studies show nothing about long term effects on weight loss and therefore nothing should be inferred about long term effects.  In terms of safety, the review study showed that use of ephedra containing supplements led to an increased risk of nausea, vomiting, psychiatric symptoms, hyperactivity, and palpitations.


      In another study, testing the effect of ephedrine plus caffeine on plasma lipids and lipoproteins, Buemann et al (1994) attempted to test the mechanism of thermogenesis and whether or not ephedrine plus caffeine was effective in causing this to occur.  They found that weight loss did not differ between the treatment group and the placebo group.  However, by week 8 of the study, a decrease in HDL cholesterol could be observed for the treatment group, likely because of the depletion of fat stores in those taking the supplement. 


          However, a conflicting study was published by Bell et al (1999).  This group showed that the metabolic rate of the treatment group taking an ephedrine and caffeine containing supplement did not cause sufficiently increased internal bodily temperature in comparison to a placebo group. It was suggested that homeostatic heat loss mechanisms offset the increase in bodily temperature, in which case the aspirin was not doing its supposed job. 


          Haller et al(2000) did a review of 140 reports of adverse events associated with dietary supplements containing ephedra.  They concluded that in 31% of the cases, the probable cause of the adverse event was related to ephedra.  In addition, of this 31%, 47% of these cases showed cardiovascular events, while 18% showed central nervous system events.  Therefore, it can be concluded that ephedrine containing supplements do pose some risk to health. 


          The picture concerning the safety of ephedrine is thus unclear. This was further illustrated by Kalman et al(2002), who attempted to determine the effects of an ephedrine/caffeine combination on cardiovascular health in adults using a randomized double blind placebo study comparing the actual Xenadrine product with a placebo. They observed no significant difference between the two groups in terms of cardiovascular events. 



Conclusion: What can be said about Xenadrine and its efficacy? Is it safe?


          At this point you are probably quite confused as to whether Xenadrine does actually do what advertisers claim and as to whether it is safe.  Some studies show substantial weight loss while others do not when taking supplements containing the ephedrine and caffeine combination.  In addition, some show that adverse events are related to the use of these supplements, while others show no significant difference between the supplement and a placebo.  There is no definite yes or no answer as to whether Xenadrine works.  It is largely depends on the individual, as everyone responds differently to different things. Because no or few long term studies have been documented, the long term effect of these supplements is also ambiguous. This fuzziness concerning Xenadrine should be reason enough for you to look hard into whether or not you want to test a supplement that has been shown to cause some serious problems in some cases.  Perhaps this will make the picture clearer then. 


          WebMD states, “A weight-loss supplement containing ephedrine reportedly contributed to the death of Baltimore Orioles Steve Belcher, who died of heat stroke when his body temperature reached 108 degrees.” (

Weight loss supplements do bring with them possible severe consequences, however, this is often obscured by the messages passed on by advertisements.  Most experts will say that diet pills are not an effective way of losing weight.  If you want to combat a weight problem, the first place to look is your diet and your exercise habits. 


          In fact, the US and Canada have begun a sweeping look into the safety of ephedrine containing supplements in recent months.  The effects of ephedrine are similar to amphetamines or uppers, which causes the heart to beat faster and has profound effects on the central nervous system. This is certainly a danger. As with any decision, a cost-benefit analysis is important in deciding whether or not to try Xenadrine.  From the staggering uncertainty concerning its effectiveness and its safety issues, it seems clear that the costs probably outweigh the benefits. 





Bell, DG; Jacobs, I; McLellan, TM; Miyazaki, M; Sabiston, CM.  “Thermal Regulation in the Heat during Exercise after Caffeine and

          Ephedrine Ingestion.”  Aviat Space Environmental Medicine, June 1999,  pgs. 583-8.


Boozer, CN; Daly, PA; Homel, P; Solomon, JL; Blanchard, D; Nasser, JA; Strauss, R; Meredith, T.  “Herbal Ephedra/Caffeine for

          Weight Loss: A 6-month Randomized Safety and Efficacy Trial.”  International Journal of Obesity and Related Metabolic Disorders, May 2002, pgs. 593-604.


Buemann, B; Marckmann, P; Christensen, NJ; Astrup,A.  “The Effect of Ephedrine Plus Caffeine on Plasma Lipids and Lipoproteins During

          a 4.2 MJ/day Diet.”  International Journal of Obesity and Related Metabolic Disorders, May 1994, pgs. 329-32.


Haller, CA; Benowitz, NL. “Adverse Cardiovascular and Central Nervous System Events Associated with Dietary Supplements Containing

          Ephedra Alkaloids.”  New England Journal of Medicine, Dec. 2000.


Kalman, D; Incledon, T; Gaunaurd, I; Schwartz, H; Krieger, D. “An Acute Clinical Trial Evaluating the Cardiovascular Effects of an Herbal

Ephedra-Caffeine Weight Loss Product in Healthy Overweight Adults.” International Journal of Obesity and Related Metabolic Disorders, Oct. 2002, pgs. 1363-6.


Molnar, D; Torok, K; Erhardt, E; Jerges, S. “Safety and Efficacy of Treatment with an Ephedrine/Caffeine Mixture. The First Double-Blind

          Placebo-Controlled Pilot Study with Adolescents.”  International Journal of Obesity and Related Metabolic Disorders,

           Dec. 2000, pgs. 1573-8.


Shekelle, PG; Hardy, ML; Morton, SC; Maglione, M; Mojica, WA; Suttrop, MJ; Rhodes, SL; Jungvig, L; Gagne, J.  “Efficacy

          and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance: A Meta-Analysis.”  JAMA, March 2003,

          pgs. 1537-45.



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