Resumen
Oily skin is a problem for a large number of people, especially in tropical countries. This condition results in comedones, inflammatory acne, and other aesthetic problems in the skin. Emblica (Phyllanthus emblica L.) has a number of benefits for the skin; for instance, there were some studies that suggested that emblica has skin whitening effects, and anti-collagenase and anti-elastase activities; however, its anti-sebum efficacy has not been reported.The objective of this research was to study the anti-sebum efficacy of emblica toner on facial skin. The toner base was formulated, accelerated stability was tested, and preferences were evaluated in 10 volunteers. The toner base with the highest preference score was mixed with emblica extract. Then, the toner base and emblica toners were assessed for skin irritation by a single patch test in 30 volunteers. The anti-sebum efficacy was conducted using the randomized, single-blind, placebo-controlled, split-face method with unwashed and only-washed skin positions added to the middle of the forehead in the same group of volunteers assessed by a skin sebum measurement, SebumScale®, at 1 h before the test, once after washing, and 1, 2, 3 and 4 h after applying the toners on forehead and cheek skin. The stable toner base with the highest preference (85.6 ± 1.8%) was mixed with 1%, 2%, and 3% emblica extract. The toners were stable and did not cause any skin irritation. The 3% emblica toner was chosen for efficacy evaluation. The casual sebum levels of the forehead skin and cheek skin were 66.66 ± 7.01 and 56.12 ± 7.75 µg/cm2, respectively. The sebum level of the unwashed skin position changed (5.0 ± 1.66%) insignificantly up to 4 h (p > 0.05). In comparison, the sebum level of the only-washed skin position was recovered to the casual sebum level (99.4 ± 1.23%) within 3 h. Furthermore, the anti-sebum efficacy of the emblica toner (23.5 ± 1.24%) was higher than that of the toner base (12.0 ± 1.52%) (p < 0.05). The anti-sebum efficacy of emblica toner on cheek skin (26.9 ± 1.78%) was higher than that on forehead skin (20.1 ± 1.34%) (p < 0.05). In summary, the model of evaluation of anti-sebum efficacy used in this study has been found to be practical, and the emblica toner is safe and has apparent anti-sebum efficacy on facial skin.