The Kiehl's Hair Conditioner and Grooming Aid Formula 133 owes its unusual name to the creation process; customers testing the product during the development stage were so eager to have more that the brand’s chemists never had the chance to name the formula – and so the name ‘Formula 133’ came to life. Today, it remains just as desirable thanks to its detangling, moisturising benefits and its ability to leave hair feeling beautifully soft.