This won't be an issue because we are supplying the supplements which are going to come from an established and reputable supplier. This is not a platform where anyone can sell their own supplements.
I think you missed my point. I sign 100-1000 people up for your study. You send the supplements to them. I quickly test the supplements to find out which is which. I then send you a report that makes the days my people took the supplements look positive for efficacy. You then report the supplements are effective. I can now point to your report to sell my supplements. It doesn't matter they are not your supplier. I still benefit from people thinking a supplement is effective.