The SPF on sunscreen is visible to everyone, but not everyone knows what it is. Join us to find out!
SPF or (Sun Protection Factor) is a measure of the level of protection from UVB rays, the types of radiation that cause sunburn, skin damage, and can cause skin cancer on products sunscreen. Simply put, if your skin often burns after 10 minutes of sun exposure, applying sunscreen with SPF 15 will give you 150 minutes protection. This is an average estimate, depending on the skin type, light intensity, and amount of sunscreen used. The SPF is essentially a measure of how well the skin is protected from UVB rays, and it is not the same as helping you determine the length of exposure.
For the best skin protection, experts often recommend using a sunscreen with an SPF of at least 15, apply to the skin in an appropriate amount (usually 2mg / cm2, or about 1 ounce for the skin) and reapply every 2 hours.
Most people usually use the only ¼ to ½ of the required amount of lotion. This means efficiency is also halved. For example, if you only apply ½ of an SPF 30 sunscreen to your skin, the effect of this sunscreen is only equivalent to the maximum amount of time that SPF 15 sunscreen can protect.
What is the SPF on sunscreen? Distinguish SPF numbers on sunscreen
The SPF range on sunscreen is from SPF 15 to SPF 100. SPF 15 blocks 93% of the impact of UVB rays; SPF 30 blocks 97% and SPF 50 blocks 98%. Therefore, it can be said that sunscreens with SPF 30 only protect you 4% more than sunscreens with SPF 15.
Another way to distinguish SPF is based on photons: SPF 15 allows 7 out of every 100 photons to penetrate your skin; SPF 30 allows 3 photons to penetrate. So while you may not be able to double the level of skin protection, a sunscreen product with an SPF 30 will block half of the radiation that an SPF 15 will allow to penetrate your skin.
Experts often recommend a sunscreen with an SPF of 15 or SPF 30. Many people often ask why we do not use a sunscreen with a higher SPF because that would be the case better? SPF only makes sense to distinguish time instead of skin protection. SPF 100 does not protect the skin better than SPF 30 and vice versa.
Besides, sunscreens with high SPFs tend to focus on protecting against UVB + rather than UVA, and the duration of sun protection of SPF 50 sunscreens is not much longer than SPF 30. In addition, creams Sunscreen with high SPF will often stay on the skin longer, easily clog pores and cause skin damage, thereby accelerating the aging process.
All sunscreens are subjected to SPF testing and must receive FDA certification. There are three main types of SPF testing: static SPF, 40-minute water-resistance SPF, and 80-minute water-resistant SPF. All sunscreen manufacturers must strictly follow the FDA-approved trials, ensuring that the SPF is appropriate on all sunscreens, chemicals, and minerals.