20 Facts You Need To Know About SPF

When choosing products with SPF, it is imperative to consider geolocation, not all creams protect against UVA rays and a few more facts about SPF that you need to know. Dermatologist-cosmetologist Viktoria Britko (Honcharuk) debunks myths and gives advice.

Victoria Britko (Goncharuk)

Dermatologist-cosmetologist

Fact # 1: physical and chemical filters work differently

There are two types of filters: physical and chemical. The former create a kind of "screen" on the skin, mechanically reflecting the solar attack. Most often, manufacturers use titanium dioxide and zinc oxide as physical filters. Chemical filters have a different principle of operation. All the intricate details are omitted, they absorb UV radiation, converting it into heat energy and thereby neutralizing it. As chemical filters used avobenzone (butyl methoxydibenzoylmethane), salicylates (salicilates), cinnamates (cinnamates). Ideal when the product contains two types of filters.

Fact # 2: there are two types of UV radiation

There are three main types of UV radiation: UVA, UVB, and UVC. It is UVA that is harmful to the skin - it increases the risk of developing cancer, causes burns and pigmentation. UVB rays are not harmful to the skin and are almost completely absorbed by the ozone layer. They pose a danger only to the cornea of ​​the eye. Therefore, high-quality sunglasses provide protection against two types of radiation.

Fact number 3: protection must be selected, taking into account the skin phototype

In dermatology, there is such a thing as erythemal time. It refers to the minimum dose of sun exposure, after which visible redness appears on the skin. This is an individual indicator.

Its value depends on the phototype, of which, according to the classification of the American dermatologist Fitzpatrick, there are five: 1 - skin that practically does not tan, often with freckles, characteristic of the owners of light eyes and hair; 2 - skin prone to burns, typical for people with light or dark blond hair and light eyes; 3 - well tanned skin, not prone to burns, typical for people with dark hair and dark eyes; 4 - the skin tans perfectly, does not burn, is not prone to the appearance of freckles; 5 - very dark skin, never burning, - sun protection is at the genetic level.

If you are a blue-eyed blonde, this is most likely the first phototype in which there is a high risk of burns. In this case, you need a cream with the highest SPF level.

Fact number 4: there is a generally accepted formula that allows you to calculate the allowable time spent in the sun

In order to calculate the required SPF, you need to know your erythema time at a given temperature in given weather conditions. This figure must be multiplied by the one indicated on the packaging of the protective product. This gives you the time you can spend in the sun before erythema (redness) or burns appear.

For example, at a temperature of 30 degrees, the erythemal time of a girl with fair skin and blue eyes is about 10 minutes. Accordingly, with SPF 50 protection, it can spend 500 minutes in the sun (10x50SPF = 500). SPF products must be renewed after contact with water.

Fact number 5: when choosing a means of protection, you need to take into account geolocation

The sun "does not shine equally for everyone"! Its activity depends on the region. In areas closer to the equator, the rays fall at a right angle - their effect is especially dangerous and detrimental to the skin. There you need to use protection higher than the one you are used to using (the erythema time is sharply reduced). It is easy to determine the UV index in your region on the nesgori.ru website or using a special application for a smartphone. In Moscow, for example, it is quite low - about three. In Sydney it is very high - in the range from eight to ten. There, during the daytime, it is better not to appear in the sun at all, even with maximum SPF protection.

Fact number 6: you need to be able to properly dose products in the form of sprays

Sprays are characterized by a fine dispersion and a thin layer on the skin. Often it will turn out that when applied, some areas remain unworked. The protection is not enough. Sprays are strictly prohibited for use by children and those who have problems with the respiratory system.

Fact # 7: There is not too much difference between SPF30 and SPF15

SPF is not only a temporary indicator. The higher the value of the protection factor, the more sun rays are blocked by the product. But the difference between SPF30 and SPF15 is not too big. So SPF15 neutralizes 94% of the sun's rays, SPF30 - 97%, SPF50 - 98%.

Fact # 8: SPF does not need to be applied in advance

There is no need to apply the product 30-60 minutes before sun exposure, as many experts advise. SPF starts working immediately! It is quite appropriate to do this on the beach. In the first days of exposure to active sun, it is better to use products with maximum protection. Further SPF can be reduced. Never start with oils - they do not provide the protection you need. They are good for moisturizing the skin after sunburn. Use shea butter, jojoba, almond, rose hips.

Fact # 9: Most day care products already contain SPF

This applies not only to care, but also to decorative cosmetics. Most day creams range in SPF from 15 to 20. This information is printed on the packaging. See the composition. Look for ingredients: oxybenzone, sulisobenzone, PABA derivatives, octylmethoxycinnamate, zinc oxide, titanium dioxide, avobenzone.

Fact number 10: SPF products should be used even in cloudy weather

It is a myth that protection is not needed when it is cloudy.

Even when the sun is not visible at all and the sky is overcast, about 40% of the UV radiation reaches the earth. This is enough to burn the owners of the first skin phototype.

They may have freckles even in February with the "cold" sun.

Fact # 11: Using an SPF cream does not cause vitamin D deficiency

In our climate, preparations based on vitamin D, which is produced under the influence of UV, should be taken from September to March (and sometimes in the summer months). Some people are wary of using SPF creams, believing that it causes cholecalciferol (vitamin D3) deficiency. There is not a single study proving that this is really the case.

Fact # 12: SPF in foundations lasts about 2 hours

In foundations, most often manufacturers use SPF from 10 to 20. Do not use them in active sun unnecessarily. On the beach, foundation is generally not recommended. Even if you work in an office, remove and reapply the cream before going outside.

Fact # 13: women with dark skin can use products with a lower SPF

On dark skin, sunburns and age spots appear less often. This does not mean that it does not need to be protected. It is necessary, but the degree of protection may be lower.

Fact # 14: Don't use sunscreen from last season

Each cosmetic product has an expiration date. But for sunscreen filters, it is no more than a year. Check the expiration dates of all last year's products. If they have expired, feel free to throw the leftovers into the trash can.

Fact # 15: SPF cream doesn't guarantee freckle-free

Cosmetologists even have such a concept "freckled phototype". On such skin, under the influence of ultraviolet radiation, melanin is actively formed, which is distributed pointwise. No cream can stop this process 100%.

Fact # 16: the caring ingredients in products with physical filters are useless

In addition to SPF protection, creams can contain caring and moisturizing components: hyaluronic acid, vitamins, essential oils. But in products with physical filters, additional ingredients are useless. Filters create a protective "screen" on the skin surface, reflecting UV rays and preventing the penetration of skin care components. If you want to moisturize and nourish, apply the serum you use every day under the SPF product.

Fact number 17: some components in the composition of protective equipment should be avoided

Avoid parabens, strong preservatives, and allergy-triggering fragrances in your protective agents. Benzophenone can cause endocrine disruption. Retinyl palmitate is often used by manufacturers of protective products. Under the influence of UV rays, it can provoke pigmentation. Avoid using retinoid cosmetics during periods of solar activity.

Fact # 18: there is no 100% natural SPF product in nature

All natural protective products are based on oils. But their maximum SPF is 4 (SPF is considered working from 10). If a larger index is indicated on the package, there are two options: either the composition contains other filters, or this is a marketing ploy.

Fact # 19: UV radiation does not penetrate under clothing

Even lightweight fabric is a mechanical barrier to UV rays. Under clothing, the skin does not tan - this is a reliable protection against burns.

Fact # 20: hair needs UV protection too

Hair needs protection as much as skin. Not only do they lose color quickly when exposed to UV rays. Ultraviolet light dries hair, making it dull and brittle. During the period of solar activity, it is better to use special sprays and oils.