research Revisiting In Vivo the Hair Regreasing Process by the Sebuprint Method 2 citations, July 2018 in “Skin research and technology” Greasy hair spreads sebum twice as much as nongreasy hair over time.
research Development and Clinical Evaluation of Green Tea Hair Tonic for Greasy Scalp Treatment 4 citations, May 2016 in “PubMed” Green tea hair tonic safely and effectively reduces scalp greasiness.