Maybe this actually part of a study to research whether having your research subjects pay you (rather than the other way around) has an effect the results of a study.
Maybe they are taking the money that people pay him on this side and paying some other research subjects to do the same thing and is going to compare the results.
It's weird to ask people to pay to be part of a study. So maybe that is actually part of what this person is studying.
Maybe all the capsules are placebos and they are studying something else.
Can you tell I like conspiracy theories? :)
Oh I just noticed you are the person who posted this. You should do that, if this isn't what you're doing.