Sunscreen is a product one applies to the skin that absorbs or reflects some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn.
Sunscreens can be classified into physical sunscreens (these reflect the sunlight) or chemical sunscreens (these absorb the UV light).
Sunscreens aid in the prevention of squamous cell carcinomas. Many sunscreens do not block UVA radiation, which does not primarily cause sunburn but can increase the rate of melanoma and photodermatitis. Thus it is better to use a broad-spectrum (UVA/UVB) sunscreen to address this concern. Regularly applying sunscreen can slow down the development of sagging skin and wrinkles
The SPF rating is a measure of the fraction of sunburn-producing UV rays that reach the skin. In other words "SPF 15" means that 1/15th of the burning radiation will reach the skin, if we assume sunscreen is applied thickly (about 2 milligrams per square centimeter).
How often should you reapply sunscreen
Multiplying the SPF factor by the length of time it takes for you to get sunburnt without sunscreen. This is how long your skin will be protected from sunburn before you have to reapply your sunscreen.
Let me give you an example:
If you develop a sunburn in 10 minutes when not wearing a sunscreen and you are going to use an SPF 15; you will have to reapply sunscreen in 150 minutes.
10 x 15 = 150 minutes ( two and a half hours)
Take note that sunscreens with higher SPF do not last or remain effective on the skin any longer than lower SPF but must also be reapplied continually as directed. I would also advise to rather stick to reapplying sunscreens AT LEAST every 2 hours and not longer.
This is usually an opaque sunscreen that is effective in blocking UVA (responsible for aging) and UVB (responsible for burning) rays. A sunblock uses a heavy carrier oil that makes it more water resistant and contains Titanium dioxide and Zinc Oxide. The word “Sunblock” is very controversial as consumers overestimate the effectiveness of a product if labeled as such. One can only be totally protected from sun damage is you are protected agains UVA, UVB and IRA (infrared light). Roughly 35% of solar energy is IRA; it cannot be seen with the naked eye but can be felt as heat.
A common question is wether to apply sunscreen before or after a daily moisturizer. It depends on the product’s application directions but I prefer applying a chemical sunscreen (think oxybenzone or avobenzone) as a base for my moisturiser so that the ingredients can absorb into my skin more readily. If I am going to use a physical block (zinc oxide) I would rather apply it on top of my moisturizer.
Here are two of my favourite facial sunscreens:
Nimue SPF 40
It has a non-oily emulsion base; it is light-weight and offers certified high broad spectrum UVA/UVB protection.
It has anti-aging benefits and helps to reducing and preventing the visible signs of photo aging. and to effectively compliment the Nimue Skin Health Programme. Formulated to aid in DNA protection and repair.
This product works best with other Nimue products but is just as awesome on its own.
The Heliocare® ranges are clinically proven to protect your skin against daily environmental challenges and help to prevent the signs of ageing. Each product provides high-level broad spectrum UVA and UVB protection and contains Fernblock®, a patented natural complex of powerful anti-oxidants that help to prevent damage to skin cells which appear as signs of ageing.
Heliocare® Advanced provides protection and prevention and also acts as a moisturiser, while Heliocare’s Color range adds to the UVA, UVB and anti-oxidant skin-protection by enhancing your skin’s colour, tone and moisture. So it protects your skin as well as acting as a foundation and concealer for easy, everyday use.