Difference between physical and chemical filters

Until relatively recently, the deciding factor when choosing a sunscreen was whether it was accompanied by a beach ball, a hat or a bag for towels. And, once such a difficult tirade has been overcome, we have been happy for years.

As science advances today that it is outrageous and fortunately health education in the prevention of melanoma is something that both health authorities and those of us who work with different white coats have taken very seriously, there is currently a great awareness of this. . We still have a lot of field to pay, but we can proudly affirm that giant strides have been taken with respect to those times when oils of dubious origin and cream of carrots invaded us.


What is the difference between physical and chemical filters?

In the illustration we see a knight ready to protect himself from the attack of the adversary with a sword and a shield.

Physical filters

Physical filters act as a screen reflecting light. They would be the knight’s shield where attacks “bounce.” They have a great advantage, especially for the little ones, and that is that they cannot be absorbed by the skin. As a disadvantage, its cosmeticity is regulera . They tend to be thick textures that leave the skin looking whitish and white . Currently there are “micronized pigments” and the filter is in nanoparticles that minimize this drawback and “leave less white.” They appear reflected on the packaging with the word «nano». Although these micronized pigments can be absorbed to some extent, their use is considered completely safe and there is no reason to be afraid.

Physical filters are the filters of choice for those who have sensitive skin or a tendency to dermatitis.

Examples of physical filters are zinc and iron oxide, titanium dioxide, mica, kaolin, or talc. Examples of sunscreens with physical filters exclusively are  Avène 50+ mineral cream  or   Isdin Mineral 50+ Sunscreen.

Chemical filters

Chemical filters capture solar energy and transform it making it harmless to the skin. Thus, a little rough, we could say that they transform ultraviolet radiation into heat. In this case the chemical filters would be the knight’s sword, capable of deflecting the attack that comes towards them. They have the great advantage that they are very pleasant from a cosmetic point of view. But nobody is perfect: the drawback is that, although the filters currently on the market are safe, it is that when absorbed through the skin (because these filters are absorbed) they can cause certain allergies.

Chemical filters are the most popular on the market and some examples are Mexoryl, Octyl-methoxycinnamat or Tinorsob.

Are physical filters or chemical filters better?

The reality is that although the most widespread are chemical filters, there are numerous photoresists on the market that are formulated based on a mixture of physical and chemical filters. It happens the same as with our knight of the image, who as you can see has a sword and shield since with both he is better protected. And who is the young assistant who accompanies you? Stabilizers, which are included in the formulation so that the properties of the filters are preserved.

There is an erroneous belief, especially among parents of young children, that chemical filters are bad and physical filters are good . In children under three years old, physical filters must be used. From there, the combination of both filters is ideal since the chemical filters existing on the market today are completely safe and have passed the corresponding quality controls. Examples of sunscreen that combine chemical and physical filters are  Be + 50+ cream gel  or  Anthelios XL 50+ velvety milk .

When choosing a sunscreen, we must take into account other aspects, which are perhaps “less fashionable” than the types of filters, but are very relevant as the phototype of the person, if they have any type of skin peculiarity (dermatitis ) or is in a special stage of life such as pregnancy or being a baby, the place where you will have sun exposure, etc. There are also different characteristics of sunscreens that can make us lean towards one or the other, such as whether or not they include perfumes, whether they are water-resistant or water-proof (which looks the same but is not the same), etc. Remember that pharmacists are at the foot of the canyon to advise in this regard.

After analyzing the differences between physical and chemical filters, if someone wants to delve into how to choose the best sunscreen, you can take a look at this post, which is not out of date either and includes 10 key answers about photoprotection.  The IV Cinfasalud study recently published in June 2016 on perception and health habits of the Spanish population around photoprotection is also very complete .  Apparently there are great surprises in the differences with which women and men face sun protection


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