The rainy season ended several weeks early this year, and a long, hot summer has already begun in many countries. Because of the long period of strong sunlight, it is essential to take measures against ultraviolet radiation, which can cause blemishes and skin damage. In addition to hats, umbrellas, arm covers, and other physical measures to block ultraviolet rays, you can also use UV cosmetics and skin whitening products. Ultraviolet rays are the great enemy of blemishes, but if cosmetics are chosen incorrectly, they can end up damaging the skin. Let's take a look at how to choose safe UV cosmetics and whitening products.
UV-A and UV-B waves reach the dermis, damaging collagen and elastin, resulting in loss of skin elasticity, sagging, and deep wrinkles. This can lead to sunburn and cause dark spots and a dull appearance of the skin. Both types of radiation are harmful to the skin. UV-A causes sagging and wrinkles, while UV-B causes sunburn and spots. This is why it is recommended to use anti-UV cosmetics that protect against UV rays by using either a reflective agent composed of powdered minerals such as titanium dioxide or a chemical absorber such as oxybenzone.
Reflective agents have the advantage of being less aggressive to the skin, but they can not significantly improve the UV cut-off rate. Reflective agents physically reflect and reject UV rays, preventing them from penetrating the skin, while absorbers absorb UV rays by chemically converting the light into heat and other components that can benefit the skin in some way.
The effectiveness of sunscreens is measured by an index called SPF (sun protection factor). It measures how effective a sunscreen is at protecting the skin from UV-B rays. If your skin normally burns after 20 minutes in the sun, applying an SPF 15 sunscreen will keep you out in the sun without burning for about 300 minutes (a 15-times longer factor).
Each unit in the SPF value indicates the time it takes for sunburn to begin after exposure to the sun's rays, or 20 minutes. For example, if the SPF value is 25, then 20 minutes x 25 = 500 minutes, or about 8 hours before sunburn begins. However, if you take into account that the product will run off when sweating, as in summer, the problem can be solved by adding an extra application during the day. In other words, an SPF value of about 20 is sufficient to block more than 90% of UV rays.
UV-reflective agents repel UV-A and UV-B waves to the same degree, but UV-absorbing agents are not necessarily the same, and the values must be checked separately. UV-reflective agents are those that do not cause skin irritation, while those with a higher SPF value, such as 50, may cause more skin irritation. For people with skin problems such as rosacea, it is advisable to avoid absorbers and use reflectors such as titanium dioxide or aluminum dioxide, and choose an SPF value of about 20.
Recently, in Hawaii, it was learned that the state legislature has taken action to ban the use of oxybenzone and octinoxate, which are used in sunscreen absorbers, as harmful ingredients that can damage coral reefs. These ingredients are said to damage coral genes when they run off the skin of bathers or enter the ocean through wastewater discharged from washing ponds. Oxybenzone, in particular, is highly toxic and is believed to pose a risk of skin cancer.
You can also use whitening cosmetics to remove sunburn or blemishes. While we understand the desire to have clear skin, whitening cosmetics are designed to suppress melanin production by allowing the ingredients to penetrate deep into the skin. For this reason, they may contain whitening agents to destroy some of the melanocytes in the basal layer or to eliminate spots and dullness. These ingredients are not low toxicity and must be approved as quasi-medicines. Unlike ordinary cosmetics, they are quite aggressive on the skin.
Whitening cosmetics are also called "medicated cosmetics", giving the impression that they are superior to ordinary cosmetics, but most of them use synthetic surfactants to penetrate the skin, which destroys the barrier function. In addition, because there is no requirement to list all ingredients, consumers cannot know if eye-damaging ingredients are used in cosmetics that are supposed to temporarily show efficacy. It is prudent to avoid using cosmetics if you have skin problems, knowing that they are high-risk products.
The epidermis is inherently equipped with a protective mechanism against ultraviolet radiation if the skin is healthy. Soccer players have dark skin due to their exposure to UV rays, but they do not seem to have any skin problems. This is because their skin has the function to absorb the harmful effects of UV rays even though their melanin may darken due to UV exposure. For people whose sensitive skin has been damaged by chemical cosmetics, the barrier function is impaired, and the sun should be avoided as much as possible, as exposure to UV rays worsens the skin condition. For this reason, it is better to choose UV-compatible cosmetics with a reflective agent and an SPF value of about 20, rather than whitening cosmetics.