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Nettle, a natural solution for dandruff?

Dandruff is a common scalp condition. Fortunately, there are several hair treatments available to eliminate it. Among the most natural solutions, we find nettle extract. What is the effectiveness of this ingredient on dandruff? Learn more.

Summary
Published July 19, 2023, updated on October 4, 2024, by Pauline, Head of Scientific Communication — 6 min read

Dandruff: Where does it come from?

Affecting approximately one in two people, dandruff consists of small dead cells or scales that can stick together on the scalp, referred to as oily dandruff, or they can scatter throughout the hair before falling like snow onto the shoulders, which is known as dry dandruff. Dandruff appears as a result of an acceleration of skin renewal leading to an excessive production of dead cells associated with abnormal flaking. Several factors contribute to the onset of dandruff :

  • An overgrowth of fungi of the type Malassezia.

    Studies have highlighted a connection between the colonization of the scalp by fungi Malassezia and dandruff. Indeed, these parasites have lipase activity, meaning they hydrolyze the triglycerides found in sebum and release unsaturated fatty acids such as arachidonic acid. These acids, in turn, lead to abnormal differentiation of keratinocytes and anomalies in the stratum corneum. Furthermore, arachidonic acid upregulates the production of cyclooxygenases COX-1 and COX-2, molecules that catalyze the formation of prostaglandins, pro-inflammatory compounds responsible for redness and itching.

  • An overactivity of the sebaceous glands.

    The sebaceous glands are responsible for the production of sebum, playing a crucial role in protecting the scalp from dehydration. Sebum also ensures the hydration of hair fibers and gradually flows along the hair after being synthesized at the roots. However, overproduction can have negative consequences and lead to itching, irritation , or the appearance of dandruff. An environment rich in sebum is indeed conducive to the development of Malassezia , which feed on the triglycerides it contains.

  • An individual susceptibility.

    Scientific models have also shown that some individuals have a genetic predisposition to develop dandruff. This can particularly be caused by a faulty barrier function resulting from a disruption in the organization of lipids and the desquamation process. This disruption leads to abnormalities in cell renewal and a significant production of dead cells.

Is nettle a solution against dandruff?

Long considered a weed, thenettle is now a plant that holds a privileged position in the formulation of cosmetic 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 care. 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 partially 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. Thus, nettle 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 catalyzes the transformation of testosterone into dihydroxytestosterone (DHT). It's worth noting that both men and women synthesize 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 soothe the scalp by downregulating the NF-κB system, which is 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 tumor 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.

Sources

  • KHANMOHAMMAD R. & al. A Comparison of Clinical Efficacy between a Basic Shampoo with Herbal Extracts Containing Climbazole and Its Similar Sample Containing Piroctone Olamine in the Treatment of Dandruff and Seborrheic Dermatitis. Iranian Journal of Dermatology (2009).

  • Luis J. Borda & Tongyu C. Wikramanayake, Seborrheic Dermatitis and Dandruff: A Comprehensive Review (2015).

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