When I know I have a cold, I have some zinc lozenges that I start taking. IMO and many others agree that the zinc can change the blood just enough so the cold critters do not hang around as long. Well how many know and then understand how zinc and more importantly zinc dialkyldithiophosphate is relative to engine wear? Now I am not selling Zinc Additives but below are some cams that reflect premature lobe wear. In the US, the EPA mandated that the levels of zinc dialkyldithiophosphate, ZDDP, be reduced. ZDDP helps lubricate at engine start up. Older model cars have more of an issue but even our MINIs can incur this issue as demonstrated by the picture below. Higher level of ZDDP will affect the catalytic converter and all of us here would NEVER remove our cats. Here are some good articles on this issue. https://www.hemmings.com/blog/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/ https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=889147 Read them, become informed and make your own decision.