I don't know why I had such a hard time finding a citation for this. A couple years ago I had read that the piperine content of pepper increases during storage. I had used this as an example of why degradation isn't necessarily a bad thing, but rather it depends on what it is being degraded to.

I was beginning to question whether this was a real thing. Now that I wasn't looking for it, here I find it. I was actually searching for proper storage of piperine. That is, how should I store it if I buy large quantities.

I'll need to read up on why they used curcumin and resveratrol. I was also planning to use curcumin because it stimulates bile release. That may be their reason as well. They used piperine because it inhibits p450 enzymes. I'm not sure why they might have used resveratrol, though I do recall hearing that it is a bioenhancer.