4 most common mistakes that make sunscreen ineffective
The toxicity of ultraviolet rays to the skin has been proven by scientists, it causes the risk of skin darkening, melasma, skin cancer so sun protection always needs attention.
Apply sunscreen close to going out
Many people consider sunscreen as the final layer of makeup, so after getting dressed, using cosmetics and sunscreen, they immediately go out. Meanwhile, sunscreen usually has to be applied about 30 minutes before going out for the cream to be effective.
And always remember to reapply sunscreen every 2-3 hours, even if you use sunscreen with a high SPF.
Because many people think that the higher the sun protection index, the better the sun protection, but this is only part of it. In fact, SPF 30 sunscreen can protect 97%, then SPF 50 increases the protection efficiency to 98%.
“SPF index does not differ in sun protection effectiveness, but in sun protection time,” said Dr. Tam.
Apply once, sun protection all day
This is a very common misconception among women today. In the morning, women apply sunscreen and use it all day long. Meanwhile, the most standard recommendation is that women need to reapply sunscreen every 2-3 hours.
In theory, 1 SPF protects the skin from UV rays for 10 minutes. Using a cream with SPF 15 will protect the skin for 150 minutes (2.5 hours), SPF 50 is 500 minutes.
|
However, this is only a basic estimate, and the protection time depends on skin type, sunlight intensity, and the amount of cream used, so it is less meaningful to help you determine the time of light exposure. Therefore, remember, every 2-3 hours you need to reapply sunscreen once for the best protection.
Not enough dose
This is also a common mistake. Many women do not apply enough sunscreen, the layer is too thin so the effect is greatly reduced. The principle of using sunscreen is that you must use enough dose, appropriate for your skin type.
Specifically, for a person 1.63m tall and weighing 68kg, applying sunscreen to the whole body requires about 30g at a time, and for the face, 1/4-1/3 teaspoon of sunscreen is needed.
If you only apply ½ or ¼ of the required amount, the sun protection effect will be greatly reduced. For example, if you only use ½ of the required amount of SPF 30 sunscreen, the SPF will be reduced by 5-6 times.
Therefore, for effective sun protection, applying enough sunscreen is extremely important to achieve optimal effect. The amount of sunscreen recommended by the FDA is: 2mg/cm2.
Only apply sunscreen when it is sunny.
According to Dr. Tam, even on cloudy days, UV rays can still damage your skin. Therefore, use sunscreen every day, not just on sunny days.
You should also choose a broad spectrum sunscreen that protects against both UVA and UVB rays, with an SPF of at least 15 or higher, especially for patients with melasma and freckles, it should be 30 or higher. You should also choose a sunscreen that is suitable for your skin type.
Dr. Tam also emphasized that no sunscreen can protect 100% from harmful ultraviolet rays. Therefore, in addition to sunscreen, you should wear long-sleeved clothes, a wide-brimmed hat, sunglasses, and limit going out in the sun during peak UV hours (from 10 a.m. to 4 p.m.).
