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Metabolife: Diet Pill or Death Wish?

  Katherine Spitz

The Product

A.) What is the purpose ofMetabolife?


Metabolife is a company that produces dietary supplements designed to trigger weight loss and produce higher energy levels for its users. However these supplements goes far beyond a simple diet pill according to the Metabolife mission statement which states, “we[Metabolife] thrive on creating products that are safe and effective. Most of all, we have pride and dedication to creating products that improve the health and wellness of our customers.” ( Thus, through weight-loss and increased energy levels triggered by the supplements, Metabolife International strives to create a better quality of life for its users. Although the Metabolife company has seven different products on the market, Metabolife 356 is the most well known and therefore the focus of this paper.
















B.) How does Metabolife 356 achieve its purpose? How does it work and what are the mechanisms?


Metabolife 356 causes weight-loss by raising user’s metabolism which causes a thermogenic response which refers to a generation of heat due to physiological processes. This response in turn metabolizes fat in the body, leaving the lean muscle in tact. Furthermore, due to the unique herbs and nutrients that make up these supplements, Metabolife 356 produces energy levels higher than those typically seen in reduced calorie diets. Finally, these dietary supplements curve and suppress appetite before meals. However, for maximum results it is important that user’s of Metabolife 356 maintain a healthy lifestyle which includes monitored diet, exercise, and hydration.


Diana Before                                      Diana After

“…I lost 75 pounds and have kept if off for almost 2 years.”


C.) What claims are made about the effectiveness of this treatment?


To demonstrate the effectiveness of Metabolife 356, Metabolife International provides testimonials on its website which illustrate the success of its users. According to one user, Diana, “The Metabolife 356® curbed my appetite, and made it extremely easy to lose weight. I have never been able to lose weight, but with Metabolife, I lost 75 pounds and have kept it off for almost 2 years. I cannot tell you how grateful I am to Metabolife. People that I went to high school with do not even recognize me. Losing weight has been one of the best experiences of my life. My self-esteem is great now, and my confidence level is through the roof. I feel like I can do just about anything now. Before I was very quiet, and reserved; now I am very outgoing, and can talk to just about anyone. My life is wonderful now!” (


While this is only one of many success stories, an obvious theme emerges about the effectiveness of the supplement. Not only do users shed pounds easily, but their weight-loss generates a better quality of life.


D.) What evidence is offered to support this claim?


In order to support the weight-loss claims made in testimonials, the Metabolife website provides several ‘facts’ concerning the safety and effectiveness of Metabolife 356. These bits of information report that obesity is a leading cause of death in the United States and can lead to several health problems including heart complications. It goes on to say that because Metabolife 356 causes weight-loss, it helps to solve the threat that is obesity. Furthermore, these facts state that all of the ingredients in Metabolife, even the controversial ephedra and ephedrine, are safe and effective when taken in the recommended doses. (


E.) Who is presenting this information, and why are they presenting it?


All of the information covered is presented by Metabolife International on their web site ( This website is designed to inform inquiring minds about their products and in turn, to produce sales. Thus, the motivation behind this presentation of information is to generate a profit for the company while creating customers satisfied with their weight-loss results.















The Research


A.) Does Metabolife 356 really work?

According to Metabolife International, Metabolife 356 contains a number of ingredients that create a ‘unique’ blend of herbs and nutrients that trigger weight loss. However, it is the ingredient ephedra, an ancient Chinese herb, and ephedrine, the synthetic alkaloid form of ephedra, which are responsible for these results. Many studies have been conducted on the efficacy of ephedra-containing dietary supplements on weight loss and all have produced similar results; these supplements do in fact cause weight loss. These results are greatly represented by a research review paper funded by the Agency for Healthcare Research and Quality (AHRQ) that took case reports submitted to the U.S. Food and Drug Administration (FDA) as well as dietary supplement manufactures and performed a meta-analysis on the reports. From this analysis the AHRQ concluded that the temporary use of ephedra/ephedrine-containing dietary supplements is associated with considerable short-term weight loss. More specifically, the report suggested that users of ephedra/ephedrine-containing supplements lost around 1.3 more pounds per month for up to six months in comparison to users who received placebo controls. These results signified an eleven percent weight loss in users as compared to their pre-supplemental weight. Yet the reports went beyond testing for single ingredients in dietary supplements and looked at the overall effect of the combination of ephedrine and caffeine versus the placebo control. The results of these reports suggested that when combined with caffeine, ephedrine-containing supplements yielded 2.2 pounds lost per month more than the placebo; a total loss of eleven percent. Finally, the study compared the effects of ephedrine versus ephedrine plus caffeine supplements and found that the addition of caffeine produced a weight loss of 0.8 more per month than ephedrine alone. The study also analyzed the effectiveness of ephedra versus the placebo and ephedra plus caffeine containing herbs and found results similar to those of the ephedrine tests. From the study conducted by the AHRQ, it was concluded that ephedra/ephedra-containing supplements did in fact cause weight-loss and that these effects were heightened by the addition of the caffeine or caffeine-containing herbs (Shekelle, Morton, Maglione, 2003). Thus, because Metabolife 356 contains ephedra (Ma Haung) and caffeine-containing herbs (Guarana) its weight-loss claims have elements of truth. These claims however, do not compare to those made in testimonials on the Metabolife website which reported users losing 75 and even one hundred pounds. Therefore, while the product does in fact cause weight loss, it is no where near the extent that Metabolife claims.

            In light of these findings, the AHRQ study pointed out two factors that disheveled the effectiveness of ephedra-containing supplements. First, the report found no data concerning the long-term effectiveness of these dietary supplements and therefore concluded that ephedra-containing supplements such as Metabolife 356 do not ensure continued weight-loss or maintenance after a six month period. To support this finding is article by Shekelle et al. (2003) that says, “The criterion not met is duration of treatment, as all trials but 3 reported less than 6 months duration of treatment.  Trails assessing 1 year of treatment are considered desirable, as are trials assessing what happens to weight after the weight loss product is discontinued.” (Shekelle, Morton, Maglione, & Suttorp, 2003, p. 1544) Thus, these articles show a weakness in the Metabolife claims to weight loss. Second, the AHRQ study conducted its meta-analysis under dose-response conditions which means that the dosage was constant throughout the studies. Therefore, little can be said about the effects of higher or lower doses on weight-loss. Since the AHRQ study was a collaboration of many individual case reports over several years time, these two parameters greatly reduce the certainty of Metabolife claims (Shekelle et al., 2003).














B.) Is this dietary supplement as safe as Metabolife International claims it is?


Just as there are many studies that show that ephedra-containing dietary supplements are effective for weight-loss, many of these studies also suggest that these supplements are not safe. At the request of the FDA, a research review was conducted which analyzed 140 reports on ‘adverse events’ or harmful results associated with ephedra-containing supplements in order to assess causation of the events. In this study, Haller and Benowitz (2000) found that 31% of cases were definitely or probably related to the use of supplements containing ephedra while 31% were possibly related. Of these 62%, they found that 47% suffered from adverse cardiovascular events while 18% suffered from adverse central nervous system events. These recorded events showed that hypertension was the most common (17 cases), followed by heart palpitations or abnormally rapid heart beats (13 cases), strokes (10 cases), and seizures (7 cases). Furthermore, within the 62% of cases, ten of the adverse events resulted in death while thirteen in permanent impairment. For example, one patient’s adverse events that were definitely, probably, or possibly related to the ephedra-containing supplement Metabolife 356 suffered from sever hypertension, cardiac arrest, and hypokalemia (abnormally low amounts of potassium in the blood), although having no preexisting conditions, died. Thus it is clear from Haller and Benowitz’s (2000) research review that ephedra-containing supplements and more specifically Metabolife 356 are directly associated with adverse events and are therefore not safe.


















            The research review paper published by AHRQ also noted the adverse events or consequences associated with supplements containing ephedra. Although the evidence of causation wasn’t conclusive, they found that ephedra/ephedrine-containing supplements are linked with two to three times more risk of nausea, vomiting, psychiatric problems such as mood changes and anxiety, autonomic hyperactivity, and palpitations. In addition, the report showed deaths (2), myocardial infractions or problems with the muscle tissue in the heart (3), cerebrovascular accidents (9), seizures (3), and psychiatric cases (5) as adverse events associated with ephedra ingestion (Shekelle, 2003). The parallels between the data of the Haller and Benowitz (2000) report and AHRQ report suggest that ephedra/ephedrine-containing supplements are associated with serious health hazards. Therefore, the Metabolife International mission statement that says, “…we strive on creating products that are safe and effective” (, is only partially true. The question thus becomes, which is more important, temporary weight-loss or long-term health and wellness?






Haller, CA & Benowitz, NL. (2000). Adverse Cardiovascular and Central Nervous System Events Associated With Dietary Supplements Containing Ephedra Alkaloids. The New England Journal of Medicine, 343, 1833-1839.


Shekelle, P., Morton, S., Maglione, M., Suttorp, M., Roth, E., Jungvig, L., Mojica, W.A., Gagne, J., Rhodes, S., & McKinnon, E. (2003). Ephedra and Ephedrine for Weight Loss and Athletic Performance Enhancement: Clinical Efficacy and Side Effects (Assessment No. 76 Prepared by Southern California Evidence-based Practice Center, RAND, under Contract No 290-97-0001, Task Order No. 9). Rockville, MD: AHRQ Publication No. 03-E022.


Shekelle, P., Morton, S., Maglione, M., Mojica, W.A., Suttorp, M., Rhodes, S., Jungvig, L., & Gagne, J. (2003). Efficacy and Safety of Ephedra and Ephedrine for Weight-Loss and Athletic Performance. Journal of the American Medical Association, 289, 1537-1545.


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