Why a Pharmacy Lab Spent a Decade on Hair Dye, and What It Means When You Buy Henna Powder
Why would a team of pharmacists, whose careers revolve around getting molecules into the body, spend nearly ten years trying to keep one out? The story starts with a dermatologist. A clinician who treats patients with hair dye allergies asked a research group at the National University of Singapore a blunt question: you know how to deliver drugs through the skin, but do you know how not to? Professor Giorgia Pastorin and her colleagues took it seriously. They worked with chemists, clinicians and dermatologists, designed and synthesised more than 20 new compounds, and shared their progress on 17 April 2026. The target of all that effort is an ingredient called PPD, the reason a box of dark hair colour can leave one person with a lovely shade and another with a swollen face. Which makes a very old plant look quite interesting again. The short answer The dried, milled leaf of the henna plant is the original plant-based hair colour, and for people who react to synthetic dyes it is often th...