>>>Lack of regulation

Here in the US, vitamins are not regulated by the FDA - BUT it's worth looking for "USP" on the label somewhere.

https://www.usp.org/verification-services/verified-mark

It's also (IMO) worth taking a look at LabDoor listings: https://labdoor.com/rankings/

Interesting that there are multiple ways for grapes to be good for us. First the skins (resveratrol) and now the seeds (procyanidin C1). But grapes are not the only sources.

Interesting as pretty-much always!