J. Cosmet. Sci., 67, 161–166 (May/June 2016) 161 Development and clinical evaluation of green tea hair tonic for greasy scalp treatment CHANCHANOK NUALSRI, NATTAYA LOURITH, and MAYUREE KANLAYAVATTANAKUL, School of Cosmetic Science, Mae Fah Luang University, Chiang Rai 57100, Thailand. Accepted for publication April 17, 2016. Synopsis Green tea has cosmetic benefi ts that include activities against androgen disorders. A hair tonic containing green tea for reduction of scalp sebum was developed and clinically evaluated. Stable green tea hair tonics were closed-patch tested and clinically evaluated in 20 volunteers for 28 days by using a Sebumeter®. Hair tonic base with glycerin and butylene glycol (total 4%) gained the highest consumers’ preference was incorporated with green tea extract. All of the products were stable and none caused skin irritation. Green tea hair tonic (2%) signifi cantly (p  0.024) lowered scalp sebum for 21 and 28 days following the application, suggesting that this topical therapy of scalp greasiness is safe and effi cient. INTRODUCTION Green tea (Camellia sinensis) has several health benefi ts including favorable cosmetic prop- erties. The herb is therefore widely used in skin care products for antiaging (1,2) and hydration (3,4), either as the single active agent or in a combination with others (5) for skin disorder treatment. Its potential as a hair growth promoter is considered to be caused by 5α-reductase activity (6). In addition, the inhibitory effect of tea against the androgen receptor also implies possible treatments for body and oral malodor (7,8). The clinical setting for hair loss frequently includes oily scalp (6), which is caused by overactive sebaceous glands (9). Excess sebum on the scalp produces the ideal environ- ment for Malassezia spp., resulting in itching and dandruff (10). Therefore, an application of cosmetics to reduce scalp greasiness should be used to manage this hair disorder. In particular, products with a long contact time, such as hair tonics, tend to have enhanced effi cacy (11). Thus, green tea hair tonic was developed and skin irritation was assessed by means of a single closed-patch test including the tonic preference. Thereafter, the devel- oped product was studied and monitored with a Sebumeter® (SM810 CK, Cologne, Germany) in a randomized single-blind, placebo-controlled clinical study. Address all correspondence to Nattaya Lourith at nattayal@mfu.ac.th.