Nettle, a natural solution for dandruff?

Long considered a weed, thenettle is now a plant that holds a privileged position in the formulation of cosmetic care products. Its stinging leaves cause irritation when they come into contact with the skin. However, once infused, macerated or dissolved in a solvent, they release an extract with purifying, antioxidant, antibacterial and anti-inflammatory properties. Thenettle is used both topically and for hair application. Among the many benefits it brings to the hair, its anti-dandruff effects can be highlighted.

A study has notably highlighted the anti-dandruff virtues of nettle when incorporated into a shampoo. This shampoo also contained piroctone, climbazole, and extracts of chamomile, rosemary, sage, peppermint, and wheat germ. However, scientists partly attribute its effectiveness to the nettle extract. The study involved 120 people suffering from dandruff, of which 60 applied this shampoo three times a week for five weeks. The other half of the participants used a competing shampoo. At the end of the experiment, the researchers noted that 80% of the people who used the nettle-based shampoo no longer had dandruff while 20% had significantly less. The anti-dandruff effects of nettle are explained by its antifungal and sebum-regulating properties. Furthermore, this ingredient is anti-inflammatory and helps to reduce the redness and itching associated with oily dandruff.

• The nettle has antifungal properties.

  The polyphenols found in nettle extract allow it to act against certain fungi such as Malassezia. Studies conducted in vitro have indeed shown that these molecules are capable of interacting with the cellular membranes of these microorganisms and altering their fluidity, thereby causing a leakage of the essential components present within them. Nettle thus helps to block the growth of fungi partly responsible for dandruff.

• The nettle has a sebum-regulating activity.

  Thenettle is traditionally incorporated into hair care products intended for individuals whose hair becomes oily quickly, due to its sebum-regulating properties. These properties stem from its inhibitory effects on 5-α-reductase, the enzyme that catalyses the transformation of testosterone into dihydroxytestosterone (DHT). It's worth noting that both men and women synthesise androgens, although their production is higher in men. DHT is capable of binding to a specific cytosolic receptor located in the sebaceous glands, which triggers an intensification of sebum production. By inhibiting this process, the nettle thus regulates sebum production and limits the appearance of dandruff.

• The nettle has anti-inflammatory properties.

  Dandruff is sometimes associated with redness and itching due to the production of inflammatory mediators following the release of arachidonic acid by fungi Malassezia. Nettle extract can alleviate the scalp by downregulating the NF-κB system, involved in immune and inflammatory responses. Studies in vitro have also proven that this ingredient reduces the synthesis of interleukins IL-2 and IL-1β and the tumour necrosis factor TNF-α. These are pro-inflammatory cytokines involved in itching. Thus, in addition to acting directly on the causes of dandruff, nettle can also alleviate the discomfort associated with it.