A quick search on the NET will show you that, among others:
Castrol Syntec power System
Valvoline Engine Treatment
Motor Up
Prolong
Slik 50
Duralube
STP Engine treatment
have all been sued by the Federal Trade Commission for false and deceiving advertizing, unproven/untrue statements with the sole objective of luring customers.
Fines for some of them were up to $20Millions.
I rest my case.
jackD