This is a nice introduction to critical thinking in the face of claims made in the "anti-aging" marketplace - as well as in reputable branches of aging and longevity research: "Although there are myriad ways to undermine a research study, [readers] should be on the lookout for issues that frequent the Longevity and Aging literature. A common issue is the extrapolation of animal (or even yeast or bacteria!) longevity data to humans. Beware studies that avoid mentioning the study species in their abstract or conclusions. They may want you to over-estimate the import of their work. ... beware of surrogate markers or intermediate endpoints. Have the investigators 'cherry picked' only the markers that prove their bias? ... Look for adequate numbers of study subjects. In general one needs over 20 individuals per study arm to approach adequate approximation of a general population."

Link: http://www.agemed.org/p/4,4.html