The similarities are mostly superficial - the Substance is about cloning and consciousness transfer, where this one is about a virus that makes you younger and hotter ( metaphorically and literally ).
The bad guy of the Substance is the main character's vanity and self-loathing, and the bad guy of this one is a cackling cartoon villain who orders people killed while getting a blowjob on his yacht.
The series wasn't bad - interesting enough for me to watch the first 3 episodes and be interested in where it is going. The steel eyepatch hitman is a bit much though.
I can't help but feel that this series was filmed with boobs and then told to cut them out afterwards - there's a surprisingly large amount of boob related plot that really makes no sense or impact with never seeing them.
