Just reading the claims made for the stuff (like "improves compression" and "carbon nano lubricant") it looks like typical snake oil. That is the case with the vast majority of such products.

If you suspect your oil consumption problem is due to carbon buildup on the oil control rings Scotty recommends ATS 505 Carbon Clean. (That's a product that you run through the engine to do its cleaning job and then remove by changing oil and filter.) You might also try replacing your PCV valve to see if that helps. However an 18-year-old high-mileage engine could just be wearing out.

All of those products are basically snake oil. 

Given that it's a Toyota Prius with high mileage, the engine is probably wearing out. The hybrid engine starts and stops, powering the electric motor. Every time that engine stops, the oil loses oil pressure and drops back into the sump. When it restarts, it takes a few seconds to fully build up pressure again, and in that time, only residual oil film from the previous starting is on the engine's moving parts. 

There's an outside chance that the piston rings my be partly stuck. You might try this: https://www.atschemicals.com/, use the oil system treatment, in the chance that the piston rings are stuck. That can happen, if you don't change your oil frequently enough.

I would caution that if you've made a habit of changing oil late, it won't make any difference/ could make your oil burning problem worse. 

A car that old, I would think your leaking oil as much as your burning oil...put white cardboard under it when you park it for a day or two..