We are sure that you already know that we always recommend to everyone to protect the skin from the sun throughout the year, but it is not amiss to repeat the same, especially at this time when the sun is coming back and most of you are already thinking about the annual vacation. Do you think enough about the less "rosy" side of sunbathing and proper protection against the harmful effects of UV radiation? Today we will once again remind you how important quality UV skin protection is.
TYPES OF ULTRAVIOLET (UV) RADIATION
There are three types of UV radiation - UVA, UVB and UVC. UVA rays (wavelength 320-400 nm) penetrate into the deeper layers of the skin (dermis) and are responsible for aging and long-term skin damage that is not acute. UVB radiation (wavelength 290-320 nm) is responsible for acute damage to the surface layers of the skin, i.e. burns . According to the English expressions aging and burn , it is easy to remember the impact of UV A and UV B radiation on your skin. There is also UVC radiation, but you never hear much about it because it does not "reach" the Earth, considering that the atmosphere successfully eliminates it.
WHAT IS SPF?
To begin with, it is necessary to keep in mind that the protection factor only describes the ability of the product to protect you from UVB rays. It is thought that a person with completely normal skin can last 10 to 20 minutes in the sun without burning, although of course this time can vary depending on a number of factors such as where you are and the time of day you are exposed to the sun. Let's say that you can stay in the sun for 10 minutes without getting burned. If you use SPF30, then that number rises to 300 minutes, so the number in SPF indicates how many times longer the time you can spend in the sun without burning, compared to staying in the sun without protection.
It is widely believed that SPF15 "repels" 93% of the air, SPF30 97%, and SPF50 98%. As can be seen, a higher protection factor means better protection, however, the higher the factor, the smaller the difference in protection compared to the first lower SPF.
If SPF refers only to UVB radiation, how will you know if your preparation also protects you from UVA radiation? Products that have been proven by extensive research in laboratories to protect against UVA radiation are labeled as broad spectrum products. At the moment, if the product you are using has this label, it is considered that protection against UVA radiation is satisfactory, that is, two factors determined by standardized methods are met. The first factor is that the ratio of UVB:UVA protection is less than or equal to 2.5, and the second is that the filters cover predetermined critical wavelengths related to both types of UV radiation.
In Europe, the degree of UVA protection is determined by the in vitro method prescribed by the COLIPA guidelines. Measurements are performed spectrophotometrically and are standardized and reproducible, i.e. they can be repeated and can be transferred from laboratory to laboratory. The obtained results are correlated with the in vivo results, which ultimately gives information about the degree of protection against UVA radiation.
However, such a label does not show precisely what kind of protection it provides, as is the case with SPF and UVB radiation. However, recently the PA+ labeling system has started to appear. Given that UVA radiation stimulates the activation of melanin, which causes the skin to darken, certain groups tried to determine the ability of various preparations with a protective factor to protect against UVA radiation using the PPD (Persistent Pigment Darkening) method. The test is performed by exposing several subjects to UVA radiation, where one part of the skin is protected, while the other is not, and the difference between the two parts is observed. The problem with this test and the reason why this kind of UVA protection labeling has not yet taken off is that there is no standardized system for evaluating the results. Considering the aforementioned lack of standardization in the interpretation of results, they are interpreted differently from country to country, depending on the different scoring systems of each country. The biggest disadvantage of the PA+ classification of UVA protection is the fact that only skin darkening is observed. The first problem with this approach is too much variability between subjects because certain people darken much more than others, and the second is that with UVA radiation what is more problematic is what we "don't see", i.e. the effects on the deeper layers of the skin that are not checked with this approach.
TYPES OF PROTECTIVE FILTERS
You are almost certainly aware that filters are divided into two groups - chemical and physical filters.
The basic difference between these two groups is that chemical filters have a specific absorption spectrum and protect by absorbing radiation of certain wavelengths. In contrast to them, physical filters prevent the passage of radiation, or rather - reflect it. Previously, chemical filters were considered less capable of protecting against UVA radiation, but today filters such as Tinosorb, Uvinul, Mexoryl and Parsol have been developed, which are very effective in the fight against both types of radiation.
Chemical filters are generally more cosmetically acceptable, they fit into products more easily, and products that contain them spread better, and it is necessary to apply less product for equal protection. Their disadvantage is that they need to be applied to the skin 20 to 30 minutes before sunbathing in order for the protection to be adequate, but also that due to their characteristics, they have a slightly higher potential for causing irritation on extremely sensitive skin. Physical filters are cosmetically unsightly both for the manufacturer (they are difficult to smear, have a dense structure, and it is difficult to fit into formulations), but also for the user of the product (they can leave a white mark after application, which is why people apply too little of them). They protect immediately after application and are somewhat more stable and have a longer shelf life. In certain formulations, they can be washed off the skin by bathing or sweating, but in general, physical filters need to be reapplied less often than chemical filters. In translation, each of the two mentioned groups has its own advantages and disadvantages, and your products will most often contain different combinations of them, with the aim of achieving optimal protection with a satisfactory product texture.
PROPER APPLICATION OF SPF
Finally, there is one more fact that is extremely poorly known to everyone, and is of key importance for sun protection. Namely, everything stated earlier in this article (all research, determining the protective factor and the like) applies only if you apply the sunscreen correctly. Although you probably think that this part of the text is nonsense and that you must apply the cream correctly and thus get the promised protection, research has shown that only 30-40% of people apply SPF correctly, and most of us achieve only 40% of sun protection compared to to the one he thinks he has.
Namely, all researches were carried out using 2 mg of preparation with a protective factor per 1 cm 2 of skin. Let's translate that into more practical units. You should divide your body into 8 regions: head/neck, chest, upper back, arms, lower back, abdomen, front of legs, and back of legs. On each of these parts, you should apply as much cream as you need to draw a thicker line from the tip of the middle finger to the bottom of the hand, or palm. If you belong to the majority who use sunscreen for several years in a row, keep in mind that you are not applying enough and you are not protected from the sun as much as you think you are.
Remember, enjoying the sun shouldn't cause anyone anxiety, as long as you do it safely and responsibly. In our assortment you can find Solar I, a light cream with a fluid texture that has a high SPF30 , filters of the latest generation and protects the skin from UVA and UVB radiation.
LITERATURE:
- Diffey BL, Grice J. The influence of sunscreen type on photoprotection. British Journal of Dermatology , 1997, 137, 103-105
- What Is Ultraviolet (UV) Radiation?, 2017, https://www.cancer.org/cancer/skin-cancer/prevention-and-early-detection/what-is-uv-radiation.html , accessed 4 July 2019
- Ask the expert: Does a higher SPF sunscreen always protect your skin better?, 2018, https://www.skincancer.org/skin-cancer-information/ask-the-experts/does-a-higher-spf-sunscreen- always-protect-your-skin-better , accessed 5 July 2019
- The sunscreen guide. For lost souls, 2018, https://chemistconfessions.com/basics/the-sunscreen-guide-for-lost-souls/ , accessed 4 July 2019