There may be some oil additives that are beneficial, but Prolong is not one of them. Avoid any using PTFE (aka Teflon.) Check out this article Snake Oil! note the footnote about Prolong:

October 1998 issue of Consumer Report magazine about
an oil additive called "Prolong". Their nationwide television
ads claim that this oil treatment bonds a 1-molecule-thick
low-friction coating to metal surfaces in the engine resulting
in longer life, better mileage, more savings. It supposedly
protects the engine even when the oil is drained. The ads show
Al Unser driving a Dodge Viper on a racetrack in the Mojave Desert
without oil or drain plug, and a testimonial from a woman who
supposedly drove from Santa Barbara to L.A., almost 5 hours,
with no engine oil.

Consumer Report took two factory rebuilt GM 4.3 litre V6 motors,
had them installed into Chevy Caprices, broke them in with regular oil,
changed the oil and filter, added Prolong to one engine, drove another
hundred miles or so to let the stuff take effect, then drained
the oil out. Both engines failed simultaneously after 5 miles
and about 13 minutes.