From the SENS Foundation: "To date, the dominant therapeutic strategy for both specific age-related diseases and (to the extent that it has been contemplated) the degenerative biological aging process itself, has been based on altering metabolic pathways. Biomedical research has centered on the detailed understanding of pathways seen to be contributing to disease etiology or pathogenesis, and the identification of putatively dysfunctional components hormones, receptors, enzymes, cytokines, etc), which are then targeted for manipulation by small molecules or other means in hopes of normalizing function and thereby alleviating symptoms or slowing progression of pathology. ... there is a critical flaw in the unconsciously-drawn analogy between its use in the development of therapies to manage specific diseases, and its potential for the treatment of the degenerative aging process. Unlike most non-communicative diseases, degenerative aging is not the result of the dysfunction of metabolic pathways, but of the the undesirable long-term side-effects of their normative biochemistry. Put another way: biological aging is the pathological result of perfectly-functioning, [healthy] metabolic processes. ... Thus, transposing the conventional drug-development pathway onto the aging process necessarily entails interfering with the normal metabolism - and doing on an indefinite basis, from the day that a 'patient' first begins therapy until his or her death. But of course, those same pathways evolved to ensure survival and fitness, and their existence and the normal mode of regulation are the very basis of ordinary health and function. We interfere with the intrinsic operation of such pathways at our peril."