"Insufficient" dosage leads to "no effect" or "small effect"?

My assumption is that scientific researchers need to "show immediate results" and that is why they use such, in some cases, massive dosages.

We, on the other hand, do not need to see such "immediate results". 

We only need to ensure that some senescent cells are eliminated. We only need to ensure that some AMPK is activated and so on.

That is my assumption.

Thoughts?