We’ve heard a thousand times, if not a million, that sunscreens should be worn when going out. But as we go out to buy the sunscreen, the seller asks us which SPF we prefer. And then we raise our eyebrows, contemplating SPF. Today, we are going to reveal all about SPF and how you should buy sunscreens.
What is SPF?
SPF stands for Sun Protection Factor. It is a number that is used to tell how much protection a sunscreen will provide against UV rays. For example, you might hear that SPF20 is good for indoors. But what are UV rays?
UV rays, or Ultra Violet rays, are harmful rays that come from the sun. These potentially harmful rays come in two types: UVA and UVB. UVA has a longer wavelength and is generally considered the cause of skin aging. UVB, on the other hand, has a shorter wavelength; it is associated with skin burns because of being more energy dense.
Here is what SPF in sunscreen means – An SPF number tells you the number of times a sunscreen can provide you protection. For example, if your skin burns for under 1 minute, then SPF 10 will save you from sunburn for 10 minutes, SPF 50 for 50 minutes, 60 for 60, and so on. But before you buy your sunscreen from sites like eBay, learn how to choose SPF.
How to choose SPF for your skin?
If your skin is gentle and gets burned easily, you will need a higher SPF. Take this simple example: if your skin can only stand 10 minutes under the sun, an SPF15 can help you withstand 150 (10×15) minutes under the sun. So, you can either apply the right amount of SPF 15 or choose a smaller amount of SPF 50. But how much sunscreen should you apply?
2 mg of sunscreen is considered to be right for 1 square centimeter of your skin. The general thought is that 1 ounce (28 grams) is enough for once. So, applying 1 ounce of SPF 50 can protect your skin from harmful UV rays for 500 minutes. But this is not the only criterion to choose the amount. Here are some other factors that impact the amount of sunscreen to be used.
- Type of weather (sunny, cloudy, etc.)
- Time of the day (morning, afternoon, evening, etc.)
- Skin type (gentle, hard, etc.)
- Other environmental factors.
UV rays in the morning and evening stay low. This is because the sun stays at an angle and most rays get absorbed by the environment. So, try going for lower SPFs if you are moving out in the morning or evening time. The sun stays strong in the noon and afternoon; choose the higher SPF when going out in the noon.
Apart from it, if you are going out in overcast conditions or are indoors, a lower SPF can provide you ample protection. Here is how different SPFs allow harmful photons (particles present in the rays) to enter our skin.
- SPF 15 – allows 7 photons (93% protection)
- SPF 25 – allows 4 photons (96% protection)
- SPF 30 – allows 3 photons (97% protection)
- SPF 50 – allows 2 photons (98% protection)
- SPF 100 – allows 1 photon (99% protection)
So, as you now know what SPF is and how to choose it, surf your favorite health and beauty website with confidence and walk under the sun with ease.