Dupe culture is the consumer movement — supercharged by TikTok — of hunting lower-cost "dupes" that replicate the formula, effect, or look of prestige beauty products. "#dupe" videos rack up billions of views, and mass and private-label brands lean in hard, while prestige brands must decide whether to fight, ignore, or wink at being duped. For communications, dupe culture is both threat and opportunity: it can commoditize a hero product, or — handled with humor and confidence — reinforce the original's status. It also reshapes AI product research, where "dupe for [prestige product]" is now a common buyer query a brand can win or lose.