I have been interested in selegeline/deprenyl as a life extension drug for quite some time, so I tried to improve my shallow understanding of the subject; unsurprsingly now I can second MR's
conclusion on the
life extension benefits of the substance:
The studies show enormous hetereogenity, the patent holder Joseph Knoll was the only one to achieve meaningful extension of maximum life span. Even extension of average and 'healthy' life span was only achieve in rats (Kitani et al. 1993 and 2005, Milgram et al. 1990) - contrary to what I believed.
In contrast similar doses decreased the life span of another rat strain (Gallagher et al. 1998).
Deprenyl did nothing for the long-lived C57BL/6J mice (Ingram et al. 1993), nor for most other mouse models. Interestingly very small doses of deprenyl increased (or rather 'normalised') the life span of female syrian hamsters, but not that of males (Stoll et al. 1994).
So assuming we want to use D for its
life extension benefits, which dose to choose?
If the effect of D varies with strain, gender and age (as described by Kitani et al.) and we're looking for a hormetic response, in the shape of an inverted U (too much decreases life span, not enough does nothing) it seems risky to extrapolate from equivocal animal tests.
So human data might be helpful to find the right dose:
So we're looking for epidemiological data on mortality/life span, data showing reduced morbidity or improved quality of life, controlled trials, or data on surrogate endpoints that are associated with clinical endpoints (maybe increased SOD/CAT in brain regions). Preferably data in
healthy humans.
The data on neuroprotection in parkinson seems
mixed. If you know of any recent studies that might be relevant to healthy human aging just post them. I haven't looked at many studies, but the aging studies in rodents.
Even if we want to use D for its nootropic/neuroprotective effect(s) it is difficult to know which dose is effective.
D is everything but safe, because a small change of the dose makes it inherently dangerous, it is not even a nootropic per se. It's a drug - Ben is right. Whether it is benefical, worthless or detrimental has not been conclusively shown, so I'd take care. But maybe there are some encouraging studies in (healthy) people I'm not aware of.
Edited by kismet, 03 October 2008 - 07:28 PM.