Resveratrol is probably good for you on balance, but the high doses used in some studies, the ongoing debate about mechanism of action, and mixed results of studies to date (follow-ups to the study discussed in the linked post have suggested no positive effects on longevity) have made the compound’s efficacy as a lifespan extension drug somewhat controversial.

It’s almost as if the drug were doing something good and something bad simultaneously, and that either or both of these consequences depended sensitively on dose and other experimental variables (like strain background). Then nearly identical studies might give very different results, making it hard to determine whether the compound is having a positive or negative effect.

Like if the drug were decreasing oxidative damage in key tissues (as one might expect) but at the same time wrecking the kidneys — which would be an especially serious issue at higher doses.