If you noticed my earlier post and accompanying reference, it’s not surprising that quercetin shortens lifespan, since it depletes intracellular glutathione. It’s for this reason that quercetin is being used experimentally as an adjuvant in cytotoxic chemotherapy. Most cytotoxic agents kill by generating intracellular free radicals and the depletion of intracellular glutathione should augment this effect. This suggests that quercetin is probably best not taken in large doses for extended periods of time. Single, or a few large doses as would be used in this context are not a problem.
This raises a potentially important issue with respect to the dasatanib + quercetin protocol in humans life extensionists, namely that if antioxidant supplements are being used, they may blunt the effect of senolytic treatment, since the final pathway to mitochondrial damage, release of pro-apoptotic caspases, and ultimately, of apoptotsis is free radical generation.