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Sunscreen helps you avoid the effects of UVA and UVB rays, which cause tanning, melasma, and aging skin. Understanding the meaning of sunscreen symbols will help you choose the right sunscreen for maximum effectiveness.1. The role of sunscreen
In sunlight contains ultraviolet rays including UVA and UVB rays. UVB rays cause sunburn, burning, long-term exposure can increase the risk of skin cancer
UVA rays can penetrate obstacles such as clothing, veils... dark spots, freckles, wrinkled skin, sagging and rapid aging.
Therefore, it is necessary to choose a sunscreen that is able to protect the skin from the effects of UVA and UVB rays.
2. Symbols on sunscreen
2.1. SPF
Chỉ số SPF có trong kem chống nắng
SPF indicates how long you can be exposed to the sun, reflecting your skin's tolerance.
SPF indicates the ability to block the amount of UVB rays affecting the skin. For example, a sunscreen with SPF 15 will block about 93.4% UVB, SPF 30 about 96.7% UVB and SPF 50 98% UVB. The higher the SPF, the more effective it will be at blocking UVB rays. However, the degree of difference between SPF 30-50 and SPF 100 is not much (SPF 100 blocks UVB rays at 98.6%). When using a sunscreen with a high index, it makes the skin secret and makes the skin prone to acne.
2.2. Index PA+ PA (Protection Factor) indicates the ability to filter UVA rays. The (+) sign after the PA on the sunscreen bottle represents the ability to block UVA rays for a certain period of time. Each sign (+) means that the product has an effect of 2-4 hours. Currently, sunscreen products have a long UVA filter index, usually from 4-8 hours (PA++) or from 8-12h (PA+++) Accordingly, the PA index is currently divided into the following levels:
PA+: UVA protection at 40-50% PA++: UVA protection at 60-70% PA+++ : UVA protection at 90% PA++++: UVA protection up to more than 90% Besides, some sunscreen products will not see the PA symbol but can instead be abbreviated as UVA -UVB, UVA/UVB, or UVA1, UVA2. The symbols will depend on the regulations of the trademarks, countries and organizations. Currently, most products block UVB rays with an SPF of at least 15. However, some brands do not offer UVA protection, so no symbols appear. on product packaging. Some products from the UK, or European countries will not provide the PA index, but you should note that the information attached to the product name includes the words "Broad spectrum" or "full spectrum" to match. This means that the product has full sun protection conditions, the effects of blocking both UVA and UVB rays at the same time.
Chỉ số PA có trong kem chống nắng
3. Sunscreen with SPF and PA how much is good?
The vast majority of users think that the higher the sunscreen index, the more effective it is, the better the skin protection. But that's not the case.If based on the normal sun protection index, the higher the sun protection index, the better the sun protection ability. However, in reality, using a sunscreen with a high index is only slightly more effective than an average sunscreen, the benefit it brings to the skin is not much.
Sunscreens with a higher index will only focus on blocking the effects of UVB rays rather than UVA rays. In addition, when applying sunscreen with a high index, it will make the skin more secretive, clogged pores, damaged skin from which rapid aging appears.
The type of sunscreen that dermatologists recommend has an SPF between 30-60. Those with an index higher than 60 should only be used for special skin areas such as treating melasma or sun allergies.
For skin conditions with inflammatory acne, you should use a sunscreen with an SPF of 15-39 to avoid unwanted irritation.
Currently, manufacturers are promoting the effectiveness of UVA protection by releasing PA++++ products. The more (+) sign after PA, the longer the time to block UVA rays.
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