The sun protection factor (SPF) is a measure of how long you can be exposed to the sun with sunscreen without burning. It indicates how much longer you can be exposed to the sun with a sunscreen product without getting sunburnt than if you used no protection at all. To evaluate the sun protection factor, the COLIPA International Sun Protection Factor Test Method is used, in which the maximum redness sensitivity threshold (Minimum Erythema Dose, MED) is calculated in a standardized way after the application of sunscreens.
The sun protection factor (SPF) is a measure of how well a sunscreen protects against UV radiation. This is mainly the UV-B component of sunlight. Sunscreens must also protect us from UV-A light in order to protect us from other light-induced skin damage. As a result, sunscreens in Europe have had to meet minimum standards for effectiveness against UV-B and UV-A radiation since 2006:
- Sun protection factor (SPF): Sunscreens with a sun protection factor of 6 or higher are ideal for protecting your skin from the sun's harmful rays.
- UV-A protection factor (UV-A-PF): The UV-A protection factor must be at least one third of the sun protection factor.
A sunscreen with an SPF of 30 should have a UV-A protection factor (UV-A-PF) of at least 10. COLIPA has issued a recommendation for in-vitro tests to check the UV-A protection factor. The symbol indicating compliance with the required UVA protection is located on the packaging and consists of a circle with the letter combination "UVA".
What sun protection factor do I need?
Everyone reacts differently to the sun. There are different skin types based on the color of the skin, hair and eyes. In addition, each skin type requires a unique self-defense time.
Skin type 1
These skin types have reddish blonde hair, light eyes, a very pale complexion and lots of freckles. They always get sunburnt and never tan. The self-protection time is 3 to 10 minutes in the sun.
Skin type 2
Blonde hair, light eyes, pale skin, often with freckles and almost always sunburnt. The self-protection time is 10-20 minutes.
Skin type 3
People with dark blonde to brown hair, a medium complexion and light or dark eyes usually tan slowly but well. They also sometimes get sunburnt easily and have 20-30 minutes of self-protection time in the sun.
Skin type 4
Hair: dark brown or black, skin color: dark, eyes: dark, sunburn is unusual, always turns brown. The self-protection time is normally 30 to 45 minutes.
Skin type 5
Black hair, dark complexion, dark eyes, very rarely gets sunburnt, always tans quickly. The self-protection time is 45-60 minutes.
Skin type 6
These skin types have black hair, a very dark complexion and dark to black eyes. They very rarely get sunburnt and have very insensitive skin. The self-protection time is 60 to 90 minutes.
How is the sun protection factor calculated?
You can roughly calculate your sun protection factor and the maximum time you can be exposed to the sun each day. To calculate this, multiply your sun protection factor by your self-protection time. This is the amount of time you can spend in the sun without damaging your skin. It is determined by your individual skin type.
A person with skin type 2, for example, has a self-protection time of around 10 to 20 minutes. With a sunscreen with SPF 20, this would theoretically mean that you could stay in the sun for 200 to 400 minutes (i.e. around three to seven hours).
However, the German Federal Office for Radiation Protection advises that only 60 percent of the calculated protection time should be spent in the sun. Even with a sun protection factor of 50 or 100, a residual amount of UV radiation still penetrates the skin and causes permanent damage to the skin, which can cause cancer.
Which SPF is recommended according to skin type?
Depending on your skin type, you should use the right level of protection for you:
Light protection: SPF 6 to 10
Medium protection: SPF 15 to 20
High protection: SPF 30 to 50
Very high protection: SPF 50+
The different filters of sunscreens
The UVA and UVB filters mentioned above prevent UV radiation from penetrating your skin, which would otherwise cause damage. A distinction is therefore made between two types of filters:
Mineral UV filters
Titanium dioxide and zinc oxide are two types of mineral UV filters. They reflect UV radiation and protect the skin from sunburn.
Organic UV filters
Organic UV filters absorb UV radiation and convert it into heat.
In sun protection products, these UV filters are combined in such a way that the required UV protection factor is achieved. The higher the proportion of filters in the mixture, the better.
What to look out for in a face cream with SPF?
It's better for your skin if you can get it used to the sun gradually: So apply sunscreen as the first step of your morning routine in the bathroom - because in spring, the sun is already quite high in the sky. As our skin is no longer used to such high levels of radiation from the winter, it has to get used to it eventually. It takes some time for melanin production to start absorbing the UV rays that would otherwise penetrate deeper into our skin and damage our cells if we were to spend time in the sun without sunscreen. Only those who use sunscreen every day can avoid wrinkles and pigmentation disorders.
Damage caused by the sun becomes visible after five to ten years at the earliest. It is therefore important that we use day creams with at least SPF 15 in everyday life. This protects us from radiation exposure during our brief moments in the sun. However, you should not overestimate this protection. A sunscreen with a high sun protection factor (SPF) is necessary if you spend long periods in the sun. Sunscreen filters are stronger due to the different components in this form of product. To prevent sun damage, it is important that you apply sunscreen to any skin that is exposed to the sun - not just your face. Make sure you also apply sunscreen to often overlooked areas such as ears, neck, hands, arms, legs and scalp.
Facts about the sun protection factor
- They also tan with sun cream and in the shade, it just happens a little slower
- Children's skin is sensitive, so it is important to use sunscreen with a high sun protection factor. In addition to chemical filters, mineral filters also offer good sun protection for children.
- A loose, white T-shirt offers sun protection of at least SPF 10, while a black T-shirt offers as much as 15. If the shirt is tight or wet, the UV protection is reduced.
- There is also clothing that offers UV protection, which is particularly useful for outdoor activities in the sun.
- The intensity of solar radiation increases by around 10% for every 1000 meters of altitude above sea level.
How do I choose the right sunscreen?
The following tips will help you to choose and use sunscreen correctly:
- The sunscreen provides adequate sun protection.
- The BfS recommends that children use sunscreen with a sun protection factor of 30 or higher, and adults should use sunscreen with a sun protection factor of 20 or higher. If you spend long periods of time at high altitudes, near snow, in water or in the sun in general, you should opt for a sunscreen with a very high SPF (50+).
- The sunscreen also protects you from UV-A radiation.
- The UV-A protection is clearly indicated on the product.
- A list of ingredients is available.
- If you are hypersensitive to the ingredients of sunscreen products, you should take this into account when choosing a sunscreen product.
- Make sure you apply sunscreen before you go outside.
- Applying sunscreen 20-30 minutes before sunbathing guarantees complete protection.
- A sufficient amount of sunscreen is applied.
- You should use 200 ml of sunscreen for five full-body applications.
- It is reapplied regularly.
- Make sure you apply sunscreen every two hours, especially after swimming or drying off with a towel.
