How many hours should I wear sunscreen?

Using sunscreen correctly is not enough, you need to pay attention to the time for them to take effect.
From now on, girls often have a habit of sunscreen by covering masks, gloves, sun protection … carefully before going out to protect their skin from darkening. That’s right, but it’s not enough because UVA and UVB rays can still penetrate masks, gloves, sunblocks, etc., causing skin diseases, especially cosmetic factors. Scientific research shows that sunscreen has a skin protection effect of up to 90%.

How to calculate safe sun protection time for skin Illustration. The SPF number on the cream cover indicates the level of sun protection. Each SPF unit provides 10 to 15 minutes of skin protection. This formula is for those with little sun exposure or with another layer of protection. Example: You buy a sunscreen with SPF 30. You will take 30 x 10 (or 15 minutes) = 300 (or 450 minutes), equivalent to 5 hours or up to 7.5 hours. In addition, another method is applied to girls who are often exposed to the sun. The formula to calculate the sun protection time for the skin is based on the sun protection index and the time the skin is irritated in the sun. Depending on each skin, this formula gives different results. For example: When going out in the sun, how long does it take for your skin to start burning and red, it’s time to get irritated under the sun. The average time is about 5 minutes, the skin will show signs of itching, burning, So you have time to protect your skin from the sun with SPF 30 cream line: 30 x 5 = 150 minutes, about more than 2 hours. Whatever the formula is, sun protection is actually governed by many factors. The intensity of the sun where you live, the level of oil secretion, the perspiration of the skin, the quality of the cream used, the UVA or UVB protection, whether it’s a physical or chemical cream, etc. Therefore, the best way to determine is based on the feel of the skin. If the skin begins to “react” by sweating, it shows that the place is sunny, mildly burning, the foundation is thinner, the skin is light as if there is no makeup … are “reminding” signs that you need to reapply the sunscreen. sunny. So to determine how long sunscreen will last, the most effective way is to rely on the “voice” of the skin. Things to avoid when using sunscreen – Need to avoid water when using sunscreen: Because water will reduce the skin protection effectiveness of sunscreen a lot. Therefore, when using sunscreen, you should not bathe, or if bathing, you need to dry your body and apply sunscreen immediately after; – Avoid applying sunscreen on the mucous membranes of the eyes and mouth: Because this skin area is very sensitive and sunscreen can cause irritation, this area of ​​​​skin can be damaged; Avoid sweating when applying sunscreen: The fact that you sauna, do a lot of physical activity causes sweat in the body to escape and wash away the sunscreen, so the sun protection effect for the skin is also greatly reduced. ; Avoid combining sunscreen with other topical medications: Because it is possible that the ingredients in topical medications will interact with the sunscreen, causing skin irritation, reducing the effectiveness of the cream. Sunscreen, the healing effects of topical drugs are many.