June 2017 in “Asian journal of pharmaceutical and clinical research” This study found that a green tea extract gel was stable across various temperatures, did not cause eye irritation, and significantly increased eyelash growth compared to a placebo after two months of use in human volunteers.
May 2023 in “Jurnal farmasi sains dan praktis” In this research on cinnamon and virgin coconut oil hair tonics, F2 and F3 demonstrated stable physical properties and mild irritation potential, while formula 1 remained non-irritating but less stable regarding pH and viscosity.
December 2022 in “Journal of Tropical Pharmacy and Chemistry” This study evaluated a hair tonic formulated from oil palm leaf extract, finding it demonstrated very strong antioxidant activity and could prevent hair decolorization from sun exposure, with effective concentrations ranging from 25 to 200 ppm.
4 citations
,
October 2017 in “International Journal of Applied Pharmaceutics” This study found that hair tonics with 5% and 10% licorice extract promoted hair growth in rabbits similarly to 2% minoxidil and were generally safe, although they caused mild eye irritation at the 2.5% concentration.
January 2026 in “Journal of Innovative and Creativity (Joecy)” This study investigated hair growth tonics made with celery leaf extract and found that 4% and 9% concentrations maintained better cyclic stability than 14%, supporting their potential use in herbal cosmetic development due to favorable physicochemical stability.