The Science of Sunscreen & Ageing

Skin is the biggest organ in the body and acts as a protective layer against the external environment with a unique inherent ability to repair itself. It consists of three layers: the outer epidermis layer, a middle layer – dermis and deep layer of subcutaneous fat. Over time, there are several factors that contribute to skin ageing: the epidermis layer thins out, the ability of skin to regenerate slows down and the body produces less collagen and elastin. All these factors lead to visible signs of skin ageing such as fine lines, wrinkles and pigmentation.

Sun – The good & The bad

Vitamin D is an essential ingredient for our overall health and well-being. Vitamin D helps with bone health, immune support, blood pressure regulation and mood. Sunlight is a good source of vitamin D, however exposure to harmful UV rays is associated not only with premature photo ageing but also skin cancer.

UV rays consist of two components of different wavelengths – UV A and UVB.

UVA rays have a longer wavelength, penetrate the skin deeply leading to damaged collagen. Collagen is an essential building block and scaffold of the skin and if damaged can lead to excessive production of enzymes known as metalloproteinases as a response to the oxidative stress from UV radiation. These lead to degradation of not only collagen but also elastin, which has a major role in recoil and skin elasticity. Repeated UVA exposure leads to the repeated degradation of these essential ingredients in skin integrity thereby leading to signs of ageing including wrinkles, lines, pigmentation, and dry leathery skin.

UVB rays have shorter wavelengths and much higher energy, therefore these have a damaging effect on the outermost skin layer. Repeated exposure to UVB rays leads to DNA damage in skin cells which in time leads to uncontrolled growth of defected cells causing skin cancer.

Tanning beds typically utilise a combination of UVA and UVB and can cause not only skin ageing but also skin cancer.

Screen & Block

Sunblocks contain a combination of organic and non-organic elements such as Octocrylene & Octyl salicylate that act as physical barrier to UV radiation when applied to the skin. These elements block and protect the skin against UVB rays.

Sunscreens protect the skin via absorption of and screening of UVA rays. These contain constituents such as Zinc oxide and titanium dioxide that when applied to the skin, absorb and dissipate the rays before they reach the dermal layer of the skin.

Formulations with both sunscreen and sunblock constituents are optimal for protection against both UVA and UVB rays, thereby protecting not only against photo-ageing but also skin cancer.