On the effects of a plant extract of Orthosiphon stamineus on sebum‐related skin imperfections

Synopsis Overproduction of sebum is very common and results in an undesirable oily, shiny complexion with enlarged pores. Sebum secretion is basically under the control of 5‐α reductase, and more particularly under that of type 1 isozyme. But it is also highly sensitive to environmental factors such as temperature, humidity and food. Moreover, in Asia, the edicts of a flawless facial skin turn oily skin into a major concern for Asian women. We identified Orthosiphon stamineus leaf extract as an interesting ingredient for reducing the oily appearance of skin thanks to its ability to reduce 5‐α reductase type 1 expression in normal human epidermal keratinocytes in vitro . This was confirmed ex vivo , where Orthosiphon stamineus leaf extract was shown to reduce 5‐α reductase activity as well as the production of squalene, one of the main components of sebum that was used as a tracer of sebum. To evaluate the efficacy of Orthosiphon stamineus leaf extract at reducing sebum‐related skin imperfections in vivo , we performed two different clinical studies, one in France on a panel of Caucasian volunteers and the other one in Thailand on a panel of Asian volunteers. Using instrumental techniques as well as clinical evaluation and self‐evaluation, we could highlight that an O/W cosmetic formula containing 2% of Orthosiphon stamineus leaf extract could visibly reduce the oily appearance of skin as well as the size of pores, thus leading to a significant improvement of complexion evenness and radiance. Overall, the results obtained were better than those observed with the same formula containing 1% of zinc gluconate, an ingredient frequently used in oily skin care products.