The main ingredient in the Metabolife tablet is Guarana concentrate (seed). This naturally occurring caffeine comprises 40 mg of the 789 mg proprietary blend. This simulation of caffeine suggests that the role of Guarana in the Metabolife substance is to provide the energy boost suggested in the advertisements and promotions of the products. Two questions must be asked concerning this product. The first is concerned with whether or not the herb truly serves to enhance the subject's energy level. The second question is the uniform question of safety.
One study entitled "Pharmacological activity of Guarana (Paullinia cupana Mart.) in laboratory animals" by Espinola, Dias, Mattei, and Carlini addressed the issue of the function of Guarana (1997). The abstract of the study summed up the findings that an increase in the physical capacity of lab mice was, in fact, observed in stressful situations after prolonged treatment with the herb. This result, however, was seen only with small dosages of the guarana. The increased demonstration of energy could not be duplicated with either larger amounts of the guarana, nor with different suspensions or caffeine. This indicates that the assumed designated purpose of the guarana in the Metabolife is fulfilled.
The same laboratory experiment found that "the animals had the same average lifespan, indicating a low toxicity of guarana, even after 23 months of treatment" (Espinola et al, 1997). Another study published in the Rev Paul Med Journal by Galduroz et al. failed to prove any dangers in the herb, but "it cannot be concluded that ‘Guarana' is harmless" (1994). According to the abstract on the study of the "acute effects of the Paulinia cupana ‘Guarana' on the cognition of normal volunteers," the results of the double-blind study were negative. No further studies can prove either the safety or the hazard of the guarana.
Because studies cannot specifically make any statement regarding the safety of guarana, a chief ingredient in Metabolife, it seems rather presumptuous to draw the conclusion that Metabolife itself is completely safe. Further studies into the guarana root may reveal inherent dangers in the prolonged use of the substance and this would subsequently reflect upon the safety of Metabolife itself. Therefore, with the information provided on guarana, it cannot be concluded that Metabolife is safe.


Title   Contents Part I   Part II  Part III



Psychology Department

The Health Psychology Home Page is produced and maintained by David Schlundt, PhD.

Vanderbilt Homepage | Introduction to Vanderbilt | Admissions | Colleges & Schools | Research Centers | News & Media Information | People at Vanderbilt | Libraries | Administrative Departments | Medical 

  Return to the Health Psychology Home Page
  Send E-mail comments or questions to Dr. Schlundt


Search: Vanderbilt University
the Internet

  Help  Advanced

Tip: You can refine your last query by searching only the results by clicking on the tab above the search box

Having Trouble Reading this Page?  Download Microsoft Internet Explorer.