In the US, sales of certain nicotine pouches are soaring. The small white pouches — Swedish cousins of chewing tobacco and dip but without the tobacco leaf — are everywhere on TikTok, flaunted by young creators who pop them under their lips, review flavors and talk about the buzz. One brand dominates the trend: Zyn, a product from Sweden that has quietly become a cultural export. But Swedes are now wrestling with what that popularity means — and whether this habit is saving lives as its promoters claim.