While this is true it is hard to say they don't work. It could be a variety of reasons, not testing the product to ensure you're actually getting the same stuff, not being able to replicate what the studies used (proper vehicle, etc.). One of the biggest reasons are the actual users. Every group buy I've ever been a part of, dating back to the Derkheim group buys of PS1 and TB4 (IYKYK lol), go something like this:
Day 1 - Shedding has completely halted!
Day 7 - I don't see anything yet but I definitely "feel" like something is happening!
Day 10 - Have a couple of new vellus hairs where I haven't had hair in 10 years. This is it, boys!
Day 14/Scenario A - I checked this morning and my hairline isn't completely restored to 120 hairs/cm. I knew this was a scam. Add another one to the list, boys.
Day 14/Scenario B - Woke up this morning with intense <insert hypochondriac condition here> and have to stop using. Does anyone know where I can get something to treat my <insert hypochondriac condition here>, this totally messed me up and I can't go on with this.