Emboldened by roaring online success in the U.S., South Korea's cosmetic startups are expanding their bricks-and-mortar presence in the world's biggest consumer market, confident their mass appeal will offset the hit from tariffs. Brands like Tirtir, d'Alba, Torriden and Beauty of Joseon are in talks with major retailers to stock their U.S. shelves, company executives have said.

Korean beauty or "K-beauty" products are able to compete globally on quality, price and snappy marketing and have benefited greatly from the success of the Asian export giant's other consumer hits, namely its music, film and television.

"K-culture — things like PSY in the past, BTS, and then Korean dramas and films like 'Parasite' — those really paved the way," Tirtir CEO An Byung-Jun said.