Photoprotection: Ultraviolet Radiation and Skin Barrier

Ultraviolet Radiation and Oxidative Stress

Ultraviolet radiation (UV) induces oxidative stress by generating reactive oxygen species (ROS) that damage DNA, proteins and lipids in the skin. UVB rays (280-315 nm) are absorbed primarily in the epidermis and cause direct DNA damage, while UVA rays (315-400 nm) penetrate deeper into the dermis and generate ROS through photosensitization.

ROS activate signaling pathways that lead to activation of matrix metalloproteinases (MMP), which degrade collagen and elastin. This leads to photoaging, characterized by the appearance of fine lines, wrinkles and loss of elasticity.

Mineral Filters: Physical Protection Mechanism

Our mineral sunscreens use physical filters such as zinc oxide (ZnO) and titanium dioxide (TiO2), which scatter and reflect UV rays without penetrating the skin. These particles act as microscopic mirrors that reflect and scatter UV radiation through phenomena such as Rayleigh scattering and Mie scattering.

Zinc oxide provides broad-spectrum protection against UVA and UVB rays, while titanium dioxide is more effective against UVB. The combination of both filters ensures optimal protection across the entire UV spectrum.

Advantages of Mineral Filters

Mineral filters are particularly suitable for sensitive and reactive skin, as they do not cause photoallergic reactions and provide broad-spectrum protection against UVA and UVB rays. The formulation with non-comedogenic ingredients prevents follicular obstruction and associated comedogenic effects. Mineral filters are stable when exposed to sunlight and do not degrade, unlike some chemical filters.

Application in Cosmetic Formulas

In Collagena Professional® products, mineral filters are combined with antioxidants and moisturizing ingredients that complement the photoprotective effect. This combination ensures not only protection from UV radiation, but also maintenance of the skin barrier and reduction of oxidative stress.