UVA & UVB Rays... what do they mean? Physical and Chemical Sunscreens....whats the difference?
“What the difference between physical and chemical sunscreen and what are UVA and UVB rays” are questions we get asked at times.
We all hear we should wear sunscreen at all times during the day, even if we are inside…. but why??
Skin damage can occur after just 15 minutes of unprotected sun exposure. Studies have shown that regular use of a SPF 15 or higher reduces your chances of developing squamous cell carcinoma, melanomas, and premature skin ageing.
What’s the difference between UVB & UVA?
Ultra Violet B rays (UVB) are short wavelengths (290–320 nm) which effect mostly the keratinocytes in the epidermal layers of the skin, this makes you tan, and is the leading cause for sunburn (erythema), DNA damage, genetic mutations and ultimately skin cancers. UVB is also responsible for Vitamin D production in the skin, with this in mind some people suggest by using sunscreen it blocks the production of Vitamin D. This is not the case at all, and leaving yourself unprotected in the sun repeatedly can lead to a whole other set of serious problems.
Ultra Violet A rays (UVA) are longer wavelengths (320–400 nm) and penetrate into the deeper layers of the skin, affecting both epidermal keratinocytes and dermal fibroblasts which are responsible for the synthesis and production of collagen, play a key role in pigmented ( melanocyte) changes occurring with age. The damaging effects UVA exposure can cause photocarcinogenisis, degradation of collagen and tissues, photoaging, mutations in mitochondrial DNA. It is also responsible for cellular oxidative stress and the generation of reactive oxygen species (ROS) which damage cellular components and lead to impairment of cell functions. The damaging effects of UVA appear after years of exposure and significantly contributes to long‐term dermal structure deterioration and clinical signs of photoaging. The signs of damage include patchy/mottled pigmentation, wrinkling, laxity, sagging, and dryness to name a few.
The time of the day plays an important role too. UVA and UVB are both present from the morning , noon and ease at the end of the day but UVA is present for most part of the day as UVB strongest between 10 a.m. and 4 p.m., especially around midday. Another interesting fact of UVA is that it comes through glass, whereas UVB are nearly completely absorbed. Therefore UVA exposure is possible while indoors.
Physical Vs Chemical
Sunscreens are chemical agents that bind with skin and reflect and absorb UVA and UVB light.
Sunblocks are physical agents ("chemical free") that reflect and scatter UVA and UVB light. Zinc oxide and titanium dioxide are examples of sunblocks.
We have a variety of chemical and physical options insalon and are happy to discuss what would be best for your skin on your next visit.
