Can we increase our sun capital?

The skin's solar capital is a somewhat vague concept used to describe the skin's natural "reserve" to defend itself against the assaults of the sun's UV rays. This reserve is not infinite and depletes over time with sun exposure. When the solar capital is exhausted, the risks of irreversible damage and skin diseases significantly increase. The skin becomes more susceptible to developing pathologies related to intolerance to UV rays.

Solar capital is essentially the skin's natural defences against UV rays. It largely depends on the production of melanin inherent to each individual. Indeed, when we expose ourselves to the sun, our epidermal cells undergo the assault of UVA and UVB rays, which can destabilise the organisation of the epidermis and dermis, leading to cell death, or even the development of melanomas and/or carcinomas. To protect itself from the damage induced by UV rays, the melanogenesis mechanism is triggered. The produced melanin clusters around the nucleus of the keratinocytes with the aim of protecting the DNA from the mutagenic and carcinogenic effects of UV rays. Melanocytes of individuals with a darker phototype have a higher pigment potential, meaning their ability to produce melanin is greater. This grants them a larger solar capital.

The solar capital is predominantly dependent on the phototype, an unchangeable element determined at birth.

Furthermore, the sun protection factor also depends on the regenerative abilities of skin tissues. Indeed, UV rays trigger the release of pro-inflammatory cytokines in the skin, molecules that intervene at various stages of inflammation. They particularly promote the synthesis of adhesion molecules, immunoglobulins that play a significant role in controlling the circulation of leukocytes. The circulation of pro-inflammatory cytokines in skin cells is notably manifested at the macroscopic level by irritations, itching, or even redness. The regenerative potential of skin tissues also depends on genetic factors and decreases as the skin is assaulted by UV rays. Therefore, it cannot be increased either.

The key takeaway : The sun capital is determined at birth and decreases with each exposure to the sun. Since it cannot be increased or restored, the best course of action is to preserve it by protecting your skin from UV rays.