Sun and self-protection
If you are in the sun, your complexion will change depending on your skin type. This is related to the so-called melanin, the tanning pigment of the skin. Melanin is nothing more than a body's own light protection filter, because it converts the UV radiation of the sun into heat.
Of course, there are no aesthetic reasons why this self-protection mechanism of the skin exists at all. UV radiation damages the skin when overdosed, makes it red (even sunburn) and promotes its aging or even skin cancer. How fast this is the case depends on the individual self-protection time. This is the period of time when you can expose your untanned skin to the sun without getting sunburned. Find out more about what type of light protection you are here.
- The self-protection period should be taken with caution, as the actual self-protection may be lower depending on the time of day, season or location.
- Those who do not exactly correspond to the southern type should be careful. The limits of the body's own protection are quickly reached, especially in exposed areas such as the face, neck, ears and hands.
Sun cream prolongs self-protection
Fortunately, there are sun protection products that protect against UV radiation as far as possible - as long as they are used correctly. The following must be observed here:
- The SPF (sun protection factor) is a value determined in the laboratory under laboratory conditions. UV light always hits the skin evenly in the laboratory, which is never the case in reality.
- Clouds, the ozone layer, the position of the sun (and the associated UVB radiation of varying intensity), a stay in snow or water are only moderately comparable with the time span calculated under laboratory conditions.
- Don't just rely on the number on your sunscreen product - it can always be a guide.
- Never use the calculated protection time completely after applying sun cream.
- After about a quarter of the time, take measures to prevent sunburn or minimise the risk of long-term effects.
How much sun cream do I need?
In order to achieve the promised sun protection factor, the product must be applied generously - this has to do with the regulations according to which the sun protection factor is tested and determined in the laboratory.
Accordingly, one should apply 2 milligrams of sun protection per square centimeter of skin. This corresponds approximately to ¼ Teaspoon for the face or a schnapps glass full for the whole body. However, these specifications are only rules of thumb.
- If you use less sun cream, the light protection is also lower, much like the opacity of wall paint decreases if you apply too little of it.
- Older people naturally need more sunscreen than smaller people.
- An average adult comes to 36 millilitres to provide the whole body with sufficient sun protection. Small measuring aid: This corresponds to a scarcely filled shot glass.
- If this quantity appears too high when applying the individual batches, the sun cream can also be applied in two layers.
When the cream goes swimming
Those who bathe or sweat a lot due to sporting activities should take the precaution of applying cream regularly. To be on the safe side, you should renew your sun protection every 2 hours on the beach, for example.
Attention, but this does not prolong the duration of your stay in the sun!
- In principle, sun protection is considered "waterproof" if half of the protection is still available after two 20-minute bathing sessions.
- Unfortunately, the actual water resistance of sunscreen is very different in tests.
- The predicate "waterproof" should not tempt you to deceptive safety, because your own paddling and bathing behaviour is probably quite different.
- So it's time to apply cream again here, too, in order to at least preserve the originally intended protection.
Sun cream, sun oil or spray - how much do I need?
Another sticking point of the standardized measurement methods in the laboratory is that the specific material properties of the tested formulations or filters are not taken into account. The quantity mentioned at the beginning behaves quite differently on the skin with an oil than with a cream. Unfortunately, there is no general rule for this.
- Follow the manufacturer's recommendations - paying attention to the term "recommendation".
- People have different sized body surfaces and therefore need more or less of the product.
- Also trust your common sense and in case of doubt rather apply too much or cream regularly.
This is how inorganic light protection filters work
Whether cream, spray or oil - all products have in common that they should protect against UV radiation. But which ingredients actually work in such a cream?
It's the light filters. They are roughly divided into two categories: In organic and non-organic or inorganic light protection filters. In addition, there are many products that even combine both filters. This is how inorganic filters work:
- Inorganic light protection filters consist of titanium dioxide or zinc oxide, i.e. minerals that have been ground to powder.
- The minerals contained in the sunscreen product work on the skin surface: they form a film that absorbs UV light and converts it into heat.
- In addition, the inorganic filters titanium dioxide or zinc oxide act like small mirrors, reflect a small amount of UV radiation and disperse it.
- They are usually well tolerated, so that skin problems or even allergies rarely occur. That is why they are mainly used in lotions for children or babies.
- Another advantage: the protection is right there. A lead time of about 20 minutes, as often recommended, is not available with mineral light protection filters.
- A disadvantage: The texture of inorganic filters is usually rather heavy and with darker skin the white film can be annoying.
Small particles, big concern: The discussion about nanoparticles in sun protection
A disadvantage of mineral filters for a long time was their "wearing comfort". In order to provide a sufficiently high level of protection, a corresponding amount of pigment had to be added to the cream or milk, resulting in a white layer on the skin.
The industry has been able to further reduce the particle size, which not only significantly improves this comfort, but also the effectiveness of these filters. You've long since reached the nanoscale. This means that the particles are 100 nanometers or smaller.
To understand how big or small a nanometer is, imagine a football next to planet Earth. This corresponds approximately to the size ratio of a nano particle to football!
With the use of nanofilters, however, the discussion began that nanoparticles could penetrate the organism via the skin and have unpredictable effects there.
Numerous studies clearly give the all-clear: a health-damaging effect was ruled out. Extensive tests with sun creams containing titanium dioxide and zinc oxide have shown that no residues have been found in deeper skin layers or blood - provided the skin is unharmed.
- The particles remain on the skin or in the uppermost skin layer - assuming, and this is an important aspect, that the skin is intact, i.e. neither injured nor inflamed.
- This is why public authorities such as the Cosmetics Commission of the German Federal Institute for Risk Assessment and the Australian health authority TGA have approved the use of both substances in sunscreens.
- We find a limitation important to mention: When using spray products, make sure that they are free of nanoparticles. In sprays, nanoparticles can be inhaled via the spray mist and still get into the organism in this way.
- By the way: You can always tell whether a cosmetic product contains nanoparticles by the addition "(nano)" in the list of ingredients (INCI).
This is how organic light protection filters work
- Organic light protection filters include all those filters that do not exclusively contain titanium dioxide or zinc oxide.
- Organic light protection filters also form a film on the skin that absorbs UV light and converts it into heat.
- New and modern filters such as Tinosorb S and M additionally reflect and diffuse a small amount of UV radiation.
- Organic filters are pleasant to wear in their texture, even with high sun protection factors.
- Both organic and inorganic filters do not have to come into contact with the skin to develop their full effect. Applied to a stone surface, they would absorb UV light as effectively as on the skin.
Organic, inorganic or both?
Both principles of action have their advantages and disadvantages, a blanket pros and cons is therefore too imprecise. Organic filters in particular are often criticized, but the latest generation of these filters is very good: they are considered to be consistently well tolerated and photostable (i.e. they do not change under UV radiation).
Among the organic filters there are good and less good ones.
The less good filters are suspected of influencing the body's hormonal balance, triggering allergies or changing under sunlight and, for example, forming free radicals.
It is also complicated by the fact that there is no "one" light protection filter that offers ideal wearing comfort and the best possible UV protection at the same time.
Modern sun protection products therefore combine different filter substances
The combination of different filters provides the broadest possible protection against the UVA and UVB spectrum. In the meantime, there are even light protection filters that combine both of the above mentioned protection principles: On tiny, UV-reflecting pigments, additional organic compounds are "docked", which in turn convert parts of the UV radiation into heat.
Good filters - bad filters
Not every UV filter is good, you have already experienced that - some trigger allergies or interfere with the hormone balance. Of course, your skin condition is also important - on healthy and uninjured skin it is much less likely that UV filters get into the body. If you have now discovered a less good filter in your product and no way to switch to a product with good filters, use your existing product rather than none at all.
Here is a selection of good filters:
Tinosorb S, Tinosorb M, Tinosorb A2B, Uvinul A Plus, Octisalate,
Iscotrizinol, Mexoryl XL.
By the way - this UV filter uses HighDroxy:
- In the DAY LIGHT 30: Tinosorb S, UVASORB and Uvinul A Plus
- In the D-FENCE 50: Tinosorb S, UVASORB HEB and Uvinul A Plus
With a sun protection product you should pay attention to the following things:
- Choose a product that suits your skin type and possible skin problems.
- Your sun protection product should have a sun protection factor of at least 15, but better be higher.
- The product should protect against UVA and UVB radiation.
- To achieve the promised sun protection, the product should form an even layer between the sun and your skin.
- Let the product soak in for approx. 10 minutes, especially if you are using follow-on products or make-up. This makes further handling easier.
- Depending on the conditions, renew the protection every 2 hours.
UVA and/or UVB: good sun protection is a balancing act
Probably the most popular guide to choosing sun protection is the sun protection factor, abbreviated LSF or SPF (Sun Protection Factor). The sun protection factor - LSF for short - increases with the number of UVB filters contained in the cream: The more UVB filters, the higher the SPF.
- Which sun protection factor is suitable is completely individual and must be determined via the self-protection. This depends primarily on the skin type, but also on whether the skin is already accustomed to the sun. At the end of a summer holiday the skin already has a little more self-protection than at the beginning.
- The second criterion is how intense the sun is at the place where you want to stay. During an alpine hike in midsummer, one needs a higher sun protection factor than on a sunny autumn day in London.
In addition to the UVB spectrum, good sun cream also covers UVA radiation. If it does this in sufficient quantities (i.e. at least 1/3 of the SPF), it may carry the UVA seal in the EU:
Last but not least: Your checklist for the sun protection purchase
- Know your personal protection time that corresponds to your light protection type and select your SPF accordingly.
- Pay attention to the circular UVA symbol.
- When assessing the product, consider the required application quantity, especially for light protection products for the face: Does the texture of the product produce this? Is a double application conceivable?
- According to the current state of research, concerns about physical nano-sized filters are unfounded. If you still want to avoid mineral nanoparticles, you can easily recognize them by the (prescribed) addition "(NANO)" in the INCI list.
More information (in German):