Often regarded as a weed, the nettle is actually brimming with benefits for the skin and hair. It is even credited with the ability to delay the appearance of grey hair. Myth or reality? Learn more in this article.
What causes white hair?
The canities, corresponding to the emergence of white hair, is often associated with a decrease in melanin production by melanocytes and a gradual reduction in their number. This natural process tends to occur around the age of 35 years, although this can vary from person to person. However, it should be noted that ageing is not the only factor contributing to the appearance of white hair. Genetics also play a significant role, as do stress and nutritional deficiencies.
Studies have also highlighted that the whitening of hair is accelerated by oxidative stress. This occurs in the body following prolonged exposure to the sun's UV rays or pollution. These factors trigger the generation of free radicals in the stem cells of melanocytes, causing them to prematurely enter apoptosis. Apoptosis is the process by which cells initiate their self-destruction. This phenomenon reduces the population of melanocytes in the anagen phase, that is, the growth phase of the hair follicles, leading to hair depigmentation. Furthermore, over time, the activities of the anti-apoptotic protein BCL-2 and the antioxidant enzyme catalase decrease, facilitating the attack of melanocytes by free radicals and their entry into apoptosis.
Can nettle counteract the onset of white hair?
The nettle is a plant from the Urticaceae family, originating from the temperate zones of Eurasia. The species of nettles commonly used in cosmetics are theUrtica dioica, or stinging nettle, and theUrtica urens, or dwarf nettle. Although these plants are primarily known for their stinging nature and their ability to provoke an inflammatory reaction on the skin's surface, an extract with a myriad of benefits can be obtained from their leaves. The Egyptians notably used it to enhance the growth of their hair and make it shinier.
Regarding the preventive action of nettle on the onset of grey hair, there is to date no study that has formally demonstrated this property. However, there are reasons to believe that the hair application of this ingredient may, to some extent, help delay greying. It should be noted, however, that it seems unlikely that nettle can affect already formed grey hair. Nettle could delay greying thanks to the polyphenols it contains. These compounds have antioxidant properties and can neutralise free radicals by donating an electron due to the double bonds present in their chemical structure. Thus, nettle could protect the melanocytes, and preserve their melanin synthesis activity, essential for hair colouring.
SEIBERG M. Age-induced hair greying - the multiple effects of oxidative stress. International journal of cosmetic science (2013).
HANO C. & al. Nettle (Urtica dioica L.) as a source of antioxidant and anti-aging phytochemicals for cosmetic applications. Comptes-Rendus Chimie (2016).