Featured advertisement You probably know Geologie from their personalized skincare, 5,200+ five-star reviews, or 13+ awards. You complete a diagnostic quiz, and they give you a complete routine catered to your skin needs. That old chestnut. Well, Geologie has now dipped its toes into a new category: haircare. What can a skincare brand bring to the hair space? A line-up shampoo and two co-wash formulations with skin-loving ingredients.