Sometime during the past several years, in between the burst of the dot-com bubble and becoming Russia's weapon of choice for meddling in foreign elections, the internet turned a skin-care product formulated over four decades ago into a very modern craze. Thanks to the effusive digital praise of the countless beauty editors, influencers, celebrities, and industry experts who swear by it, Biologique Recherche's P50 is now about as recognizable a name as it gets in the world of prestige beauty. It has been called " Jesus in a bottle ," " life-changing ," and " The Best Beauty Product in the World ." It smells like vinegar and the quart of milk you pushed to the back of the fridge and forgot about for three months. Its fans will still tell you it is the single best thing they have ever put on their face.