Best answer: It can't hurt, but it's not surefire protection. Anti-microbial cases disrupt microbes and prevent them from lingering on your case, but they can't be guaranteed to kill everything the way a true disinfectant can. They're only guaranteed to work against odor and stain-causing bacteria, not every disease-causing germ known to man.

What do anti-microbial cases actually do?

Anti-microbial cases can significantly cut down on germs on your case, disrupting the outer layer of germs, bacteria, and some viruses so that they don't linger on your device and don't spread to you. However, these germ-fighting powers are only guaranteed against odor and stain-causing bacteria (opens in new tab), not illness-causing bacteria or viruses. They can be somewhat effective against other microbes — depending on how often you clean your phone and how thick a build-up you tend to accumulate on your cases — but case makers can't actually promise that they'll protect you from getting sick.

It may not be a silver bullet, but any extra bit of protection for the item I touch more than any other every day is welcome. This is especially true during flu season and the current pandemic: it might not kill every little bug, but every little bit helps.

Does this effect wear off over time?

Some cases only come with a surface coating for its anti-microbial layer, and those will wear off over time, but good cases embed the anti-microbial solution into the polymer of the case, which means that it won't wear off over time. Both Speck (opens in new tab) and Tech21 promise this baked-in solution for lifetime protection using Microban for Speck cases and BioCote for Tech21 cases.

That said, cases get dirty over time and while this case can fight germs, it can only disrupt the microbes it is directly in contact with, so if there's a film of dead skin cells and congealed sweat that's accumulated over time, take your phone out of the case and run a Lysol wipe over it to clear all of that away.

Tech21 Studio Colour

Sustainably made and germ-resistant
Tech21 uses BioCote for its anti-microbial protection, disrupting the growth of germs and bacteria that build up on your phone and damaging the little buggers at the cellular level. You can get this thin case in bright colors, it's made with plant-based materials, and this impressively thin case has 8-foot drop protection.

I like Tech21 because they are not afraid to go bright and cheerful, and we could all use more cheer in our lives. If you like your cases more grippy and dark, no worries! Speck has got you covered.

Speck Presidio Grip

Name-brand microbial protection and iconic grip
Speck is a brand that's quite well known, thanks in no small part to that iconic V groove pattern on the back of its most popular case line, the Presidio Grip. Offered in three colors, this anti-microbial case has been drop-tested up to 13 feet to help your phone survive the chaos of day-to-day life.