Thenettle extract (INCI: Urtica Dioica Leaf Extract), derived from the leaves of the stinging nettle, is a natural ingredient abundantly available in the cosmetics market. It boasts numerous properties such as antioxidant, antibacterial, anti-inflammatory... Thenettle extract is particularly considered a friend to oily skin and possesses sebum-regulating properties.
This natural ingredient is indeed capable ofinhibiting 5-α-reductase, the enzyme that catalyses the conversion of testosterone into dihydrotestosterone (DHT). Testosterone is the main androgen in men, while in women it is Δ-4-androstenedione and dehydroepiandrosterone. Within the sebocyte, these androgens are transformed by various enzymes into testosterone, before forming dihydrotestosterone under the action of 5-α-reductase. However, DHT stimulates sebum production. Indeed, when this androgen binds to a specific cytosolic receptor located in the sebaceous glands, it triggers an increase in the activity of the sebaceous glands, and therefore an intensification of sebum synthesis. By inhibiting this process, nettle thus helps to regulate oily skin.
A recent study evaluated the sebum-regulating properties of nettle when taken orally. 20 women suffering from hyperandrogenism, a condition characterised by high levels of androgens, took 300 to 600 mg of nettle extract every day for four months. Their total testosterone levels, taking into account the amount of testosterone and its derivatives, including DHT, were measured before and after the experiment. The researchers observed an average decrease of 35% in the participants' total testosterone levels at the end of the four months. The individuals' perceptions of their skin's oiliness were also collected: 20% of them noticed an improvement. This may seem small, but it is worth noting that the hyperandrogenism from which the participants suffered is a medical condition requiring regular intake of anti-androgens to be controlled. Nettle can only supplement their medical treatment, its sebum-regulating potential being more pronounced in individuals not suffering from severe endocrine disorders.