If you're talking about the FDA, the basic rule is that you can't claim a product treats or cures any diagnosable condition it hasn't been certified for. Claims like "improve concentration" and "improve sleep" are generally permissible, where specific statements like "helps with ADD" and "cures insomnia" are not.
Based on those video titles, I don't see anything which constitutes medical advice in the narrow sense. Someone could well have decided the overall effect was tacit medical advice, but these titles in isolation aren't clear violations.
Any time you see something non-specific like "boosts the immune system" or "increases energy" it means the product is likely worthless because those claims don't actually mean anything.
It's the reason so many "nutrition" companies can get away with claiming all kinds of things such as "burn fat faster". That statement means something to you and I, but it's not a medical statement.
They might be "meaningless" to actual medical professionals or people with decent knowledge of the ways that companies skirt product labelling laws. But the average layperson who might buy these products is probably neither of those things and is more likely to interpret them literally.
The article then goes on to name several videos with titles like "increase energy," "improve concentration and memory," "improve sleep," etc.
Are there any lawyers around who know of a legal definition for "medical advice" or "medical claims?" Because these videos sound a lot like medical advice despite his insistence that they aren't.
Youtube censorship sucks sometimes, but this guy experimenting on himself is not nearly rigorous enough to figure out what's really happening when he is taking these supplements. When a person sets out to improve themselves with drugs, test the process on themselves, and interpret and analyze those results themselves, it's a viper's pit of biases. Obviously the experimenter has a huge personal stake in the experiment (arguably the largest; his person is the experiment!) and that generally is great for motivation but bad for science.
I like playing with nootropics but I'm also relatively healthy and I can't imagine how damaging it might be for a seriously ill person who is taking advice from youtube in a desperate and futile attempt to improve their condition and survive. The ethics are pretty complex, above my pay grade for sure.