Eliminating acne with nettle?

Acne is a skin condition characterised by the presence of red spots or whiteheads on the face, neck, back or chest, and even nodules or cysts in the case of severe acne. If acne affects these specific areas, it is primarily because they are rich in sebaceous glands , the organs responsible for the synthesis of sebum. Although essential for skin hydration, an overproduction of this lipid mixture is one of the main causes of acne. Indeed, this can cause the obstruction of skin pores and prevent the sebum from flowing along the pilosebaceous follicles, which promotes the appearance of blemishes.

It should also be noted that an environment rich in sebum provides a favourable habitat for the bacteria Cutibacterium acnes. This microorganism, naturally present in the skin, is responsible for inflammatory phenomena in the sebaceous glands. By digesting the triglycerides in the sebum, Cutibacterium acnes indeed releases free fatty acids that exacerbate skin inflammations. Lastly, acne can also result from a slowdown in the desquamation process. When dead cells accumulate on the skin's surface, they can potentially clog the pores and lead to the development of skin imperfections.

Thenettle is a perennial plant recognised since antiquity for its cosmetic and therapeutic virtues. The Egyptians notably used it to stimulate the growth of their hair , while the Greeks used it to prepare toning lotions or ointments. Today, the nettle is incorporated into various cosmetic treatments under its INCI name Urtica Dioica Leaf Extract and is particularly used to alleviate the symptoms of acne.

• The nettle extract has sebum-regulating properties.

  Several studies have highlighted the sebum-regulating effect of nettle extract, which is beneficial for individuals suffering from acne. Indeed, a decrease in sebum synthesis is associated with a lower risk of pore obstruction, and therefore, blemishes.

  Indeed, the nettle is capable ofinhibiting 5-α-reductase, the enzyme that catalyses the transformation of testosterone into dihydrotestosterone (DHT). Let's remember that testosterone is an androgen hormone present in both men and women, although it is produced in smaller quantities in the latter. DHT operates by binding to a specific cytosolic receptor located in the sebaceous glands. This binding triggers an increase in theactivity of the sebaceous glands, and therefore an intensification of sebum synthesis. By inhibiting this process, thenettle thus helps to regulate oily skin and reduce the risk of imperfections.

• The extract of nettle possesses anti-inflammatory properties.

  Nettle can also act by reducing the inflammation of the sebaceous glands caused by acne. Indeed, recent studies have shown that this plant has a inhibitory effect on 5-lipoxygenase, an enzyme playing a key role in the metabolism of arachidonic acid. This fatty acid increases the production of cyclooxygenases COX-1 and COX-2, molecules catalysing the formation of prostaglandins. Prostaglandins are inflammatory mediators involved in the redness and blemishes observed in cases of acne.

  The anti-inflammatory properties of nettle do not stop there. This plant also has an inhibitory effect on the NF-κB system, which is involved in immune and inflammatory responses. Finally, this ingredient can also downregulate the release of interleukins IL-2 and IL-1β and the tumour necrosis factor TNF-α, which are pro-inflammatory cytokines. Thus, thanks to its various mechanisms of action, nettle can alleviate acne inflammation.

• The nettle extract has antibacterial activity.

  It has also been demonstrated that nettle extract possesses antibacterial properties and can inhibit the growth of Cutibacterium acnes. One study, in particular, focused on a plant extract composed of nettle, myrtle, chamomile, and Damask rose. The proportions used to formulate this extract were not specified. Experiments in vitro on strains of Cutibacterium acnes showed that this extract had a MIC lower than 1/2048 µg/mL. The MIC, or Minimum Inhibitory Concentration, corresponds to the lowest concentration of a product that prevents the growth of a bacterium. It should be noted that 1/2048 µg/mL is not the MIC of nettle alone. However, scientists attribute a large part of the antibacterial properties of the extract to the presence of nettle in its composition.

Note : Despite its intriguing properties for alleviating acne symptoms, it is important to emphasise that nettle extract can only be used as a supplement in the fight against acne and it can never replace treatments prescribed or recommended by dermatologists.

• BENMOUSSA A. & al. Mise en valeur du potentiel nutritionnel et thérapeutique de l’ortie dioïque (Urtica dioïca L.). Hegel (2016).

• KILIC S. & al. Efficacy of two plant extracts against acne vulgaris: Initial results of microbiological tests and cell culture studies. Journal of cosmetic dermatology (2018).