As an example of the first viewpoint, a 2004 review in "Trends in Biotechnology" written by Leigh Turner of the Institute for Advanced Study in Princeton, New Jersey stated that the products promoted by the A4M have "no credible scientific basis" and that "there are no proven, scientifically established ‘anti-aging’ medications". A 2006 review published in the "Cleveland Clinic Journal of Medicine" of the antioxidants and hormones that are promoted as anti-aging products by the A4M and the Life Extension Institute concluded that these products have "minimal to no effect on improving longevity or functional abilities." In an editorial accompanying this study, Thomas Perls stated that although many unjustified claims were made about anti-ageing products, no substance had yet been shown to halt or slow the aging process. Similarly, the National Institute on Aging, who are part of the National Institutes of Health, published a general warning in 2009 against businesses that claim anti-aging benefits for their products, describing these as "health scams" and stating that "no treatments have been proven to slow or reverse the aging process".