The best investment for your skin lies in your sunscreen - and your commitment to it! Over the years beauty trends have come and gone - from popular actives like bakuchiol, to TikTok viral skin slugging to Dr Whitney Bowe's every popular skin cycling. But without the basic level of prevention from sun protection, skin aging continuously accelerates. Your best armour is still your favourite sunscreen!
Let's go back to basics - What is sunlight?
Sunlight consists of spectrum of rays of varying wavelength. Visible light has a wavelength of 400-700 nm, while invisible ultraviolet (UV) light has a shorter wavelength (280-400 nm), and invisible infrared light has a longer wavelength (700 nm - 1 mm). The longer wavelength like infrared light, are able to penetrate deeper into the skin, yet are less likely to cause photo damage to the skin.
How does sunlight cause skin damage?
Short-wavelength UV light that interacts with skin cells generates highly reactive free radicals. These excessive free radicals (oxygen molecules) cause cell damage. The more damage they cause, skin aging is expedited, and one's risk of developing malignancies like skin cancer - basal cell carcinoma, squamous cell carcinoma and melanoma - greatly increases.
*NERDY NUGGET*
Remember those covalent bonds you learnt about in Chemistry class, while imagine 2 electrons holding hands real tight. The heat energy from the UV rays causes them to let go of each other, releasing one lone electron and leaving the other poor guy without a partner. Our abandoned friend is now looking to fill the void - so he steals another electron from the healthy neighbouring molecule. The neighbour now in turn is missing an electron, and the process goes on and on.
Usually, your body is able to neutralise or balance this by having anti oxidants! Anti oxidants are philanthropists in the body. Just as how philanthropists themselves are often self sustaining and stable before donation, antioxidants are able to give up some of their own electrons without becoming unstable or electron scavenging themselves!
What happens when there is excessive formation of free radicals with prolonged sun exposure is the production of oxidative stress. Oxidative stress is caused by the imbalance between the production of free radicals and the body’s ability to neutralise them with anti-oxidants.
How do the different components of sunlight affect my skin?
TLDR: UVB Burns, UVA Ages. HEV light has been shown to cause similar photo damage as UVA.
Because of the different wavelengths of each component of sunlight, the genotypic to phenotypic effects differ. In essence, even though all components cause direct DNA damage and indirect damage by the creation of free radicals, the visible effect on skin differs. UVB has the shortest wavelength - it affects the most superficial part of the skin which is the epidermis - as such, it causes one's skin to peel and have that "sunburnt" appearance.
UVA and HEV light have a longer wavelength and as such penetrate deeper into the skin. They have been associated with premature photoaging, hyperpigmentation, skin cancer.
What does HEV light consist of?
It is basically the blue violet parts of the visible light spectrum. Contrary to popular belief - the "blue light" one is exposed to from digital screens has NOT been proven to cause significant photoaging on your skin. It is only the HEV light from the sun that causes adequate DNA damage to evoke a phenotypical or physical change on your skin!
How does sunscreen protect me from all this damage?
Sunscreens contain either pigments that act as a physical barrier from the sun (mineral sunscreens) and cause light to be reflected away from your skin, or contain chemical filters that convert light energy into heat energy and are dissipated away from your skin (chemical filters). In both cases, the goal is to prevent penetration of light energy into the skin at the various wavelengths to prevent DNA damage.
Are all sunscreens able to protect me from all the components of the sun?
The short answer is no! All sunscreens need to be carefully formulated before having the right capabilities. As such, remember to read your ingredients list and labels before purchasing any sunscreens. We will be talking a little more about the different types of sunscreens and their coverage in later posts, so stay tuned!