Free radicals are unstable molecules that seek to stabilize themselves by capturing electrons from other molecules, thus triggering chain reactions. They are produced both by our body, via processes such as cellular respiration or psychological stress, as well as under the influence of external factors such as UV rays, pollution (fine particles, heavy metals) or cigarette smoke. The UV radiation, from sun exposure, are the main source of free radicals in our skin.
What are the different types of free radicals?
Free radicals mainly include molecules called reactive oxygen species (ROS) and reactive nitrogen species (RNS). ROS come from our environment or from cellular respiration, a process that allows humans to live and in which the oxygen we breathe is consumed in the form of energy to be transformed into water. In fact, around 5% of this oxygen is transformed into ROS, very reactive by-products. These by-products which are superoxide (O2-), hydrogen peroxide (H2O2), the hydroxyl radical (OH-) and singlet oxygen (1O2), can damage cells when produced in excess. The RNS, for their part, are nitric oxide (NO-) and peroxynitrite (ONOO-). They come from our environment or generated during nitrogen metabolism. These reactive species can interact with unstable electrons found in lipids, proteins and DNA in our body.
How do free radicals work?
In small doses, ROS play many useful roles for our body. For example, they participate in the renewal of our skin cells. However, excessive production can unbalance our natural defense systems, leading to harmful effects: damage to cell DNA, alteration of lipids and proteins, and even the death of certain skin cells. Over time, these repeated attacks weaken the structure of cells, disrupt the cells' energy plants (the mitochondria) and degrade the support network that maintains the firmness of the skin (the extracellular matrix).
What impact do free radicals have on the skin?
Our body has a natural defense system called antioxidant system, designed to neutralize free radicals. However, when these molecules become too numerous, this system can be overwhelmed. The imbalance created is responsible for a state of oxidative stress which can have visible and profound consequences on the skin. Oxidative stress can lead to hyperpigmentation, either the appearance of brown spots or other areas of irregular pigmentation, often exacerbated by exposure to the sun. With time, this stress also accelerates premature aging of the skin, manifested by wrinkles, loss of firmness, increased dryness, rougher texture and visible skin sagging. Free radicals can also disrupt the skin microbiome, leading to a situation of dysbiosis where the balance of these microorganisms is disrupted. Inflammation is another common consequence of oxidative stress and finally, in cases of intense and repeated exposure to free radicals, particularly those generated by UV rays, there is an increased risk of skin cancer, a danger that reminds us of the importance of protecting your skin every day.
Key points to remember:
Free radicals play a central role in skin aging and the degradation of skin structures. Their oxidative effects disrupt cell membranes, weaken collagen and elastin fibers (responsible for the firmness and elasticity of the skin) and can even lead to cellular mutations. These processes thus promote the appearance of wrinkles, loss of firmness and increase the risk of skin cancer. It is therefore essential to adopt suitable solutions to preserve the health and youthfulness of the skin.
