@cullinaire what, really? Cosmetics are really common in isekais, Altho mostly in those with female protagonists. Male protagonist wise tho, Isekai Yakkyoku has cosmetics/facial cream too.
@Keimichi I have read a bunch of isekai on this site but admit that I haven't gone too deep into the shoujo side of things so that makes sense. Mostly when I saw mentions of self-care stuff it was hair care or just simply a better soap. So seeing this which focuses on the restorative side of cosmetics was pretty new to me.
@Jarkko isekai authors like to think people in other worlds are dumber than their own MC. The MC will have great knowledge of products and it's manufacturing from our world to bring to the other, in which the other world doesn't have any, is inferior, or doesn't have its magical equivalent.
Usually these products are japanese food related or just bringing mayo to the populace. Asian games is also pretty big too. At least once i have seen one "inventing" the chopsticks to replace the fork.