The recipe for sun protection
Every summer, consumers and professionals have to deal with renewed doubts about the products we are using to protect ourselves from the dangerous effects of the sun.
Out of all the cosmetic products available on the market, sunscreen and sun protection products have two differentiating characteristics:
- From a regulatory standpoint, they are not classified as cosmetic products in every part of the world.
- Consumer doubts on the usage of the products: can they be used from one year to the next once opened? Are we applying it correctly? Should we re-apply? Can we use the same product for face and body? Do we need to apply sunscreen on our hair?
Considering the regulatory aspects, market globalisation and access means that there is a growing tendency to create products that might be introduced to many countries. However, in the case of sunscreens, we must realise that they do not enter under the cosmetic definition, but as OTC products. OTC or over-the-counter products are drugs that can be sold without a prescription. In countries such as the United States or Australia, these differences are in place.
Additionally, in Europe, a recommendation exists to ensure that the protection offered is of broad spectrum. All products that follow it must ensure a protection against UVA radiation that is proportional to the SPF value. The SPF value measures the protection offered against UVB radiation. Products that adhere to this recommendation are identified by the UVA symbol.
We should also take into consideration the damage done on skin structures and DNA. This comes from the free radicals that are generated through radiation, so substances that are capable of neutralising and stopping their propagation are also helping. They might not be able to absorb or diffuse radiation directly, but they are aiding the protection offered.
Another important consideration on the use of sun protecting products is the correct application of the product on the skin. Only a correct extension of the product on the skin, forming a film of uniform thickness, will offer a correct level of protection. This results in the need to use different products on body and face.
Above this, there are the different market trends that influence product development. One of the ones that have gained notoriety in later years is the search for natural sunscreen products. But is this possible? Indeed, if we look for products that include mineral sunscreens. However, we must be ready to accept that these sunscreens must have a nano particle size in order to obtain adequate protection. If our goal is to find natural products without nanoparticles, it will be hard to find products with a high enough SPF value that will offer enough protection.
The importance of broad spectrum in sun protection.
Going back to the origins of sunscreen, initially only the SPF or Sun Protection Factor was of consideration. This is simply the measurement of the capability of a product to postpone the appearance of erythema or skin redness. This sign is directly related to the exposure of UVB radiation, the one causing sunburns. However, as years have gone by, the long-term effects of UVA radiation have come to light. This kind of radiation has a higher penetration capacity without causing sunburn can be more dangerous, due to the action it has on the internal structures of the skin and the DNA. This translates into premature ageing due to solar radiation and it may even lead to the occurrence of cancerous cells. This means that when developing a sunscreen product against sunburn, but not giving the same consideration to UVA light, we are actually inducing more damage to internal structures. If we take longer to burn, we will be able to stay in direct sunlight for long and enduring longer exposure to UVA radiation.
The solution, in Europe, came years later in the form of a recommendation and not as a legal requirement. This recommendation insists on a 33% UVA protection with respect to the SPF declared on the label. Other parts of the world have their own system to apply the same kind of recommendation, like the Boots star rating or the Japanese or Australian methods.
What about blue light or infrared?
Nowadays, we are also having to consider the possible harmful effects of the visible light, namely blue light. This is the light radiation we are exposed to when we sit in front of our computer screens, mobile phones, tablets, etc. or the infrared lights, that are mainly a heat source but that could also have some effect on skin structures. We can consider these as “indoor radiation”, and we should consider these in a different way.
Recently, studies have appeared centred around photoprotective ingredients that absorb the blue light wavelength, with the goal of including this spectrum of exposure to radiation coming from technological screens.
The sun´s benefits are well known and needed.
On the other side of this debate, we should not forget that we all need a certain dose of solar radiation in order to synthesise the minimum dose of Vitamin D. For that, we should take into consideration the time of exposure, the surface, the intensity of the radiation. This intensity will depend on the latitude, the altitude, the time of day and the distance from the sun (seasons).
The human being also has an internal protective substance, melanin, that acts as a radiation filter. The amount present can be depending on several factors. The baseline will depend on that person´s genetic profile, in relation to the need to adapt of their ancestry. The final amount of melanin present on the skin will, however, be a direct result of the amount of time the person is exposed to the sun, with the body regulating the levels in accordance with the person´s habits and needs in order to offer the required protection. The success of this protection does not only depend on the correct distribution of melanin on the skin, but also on the oxidation of it and the renewal of the epidermis layers.
Therefore, any action over this complex biological system of sun protection would be ideal, and there are already several products that can boost sun protection, designed to stimulate the synthesis and distribution of melanin. Since this is not an easy feat to accomplish, it must be supplemented with other substances that can do the same function or even ingredients that will create a film over the skin that will reflect these radiations. This is the case of the physical filter, Titanium Dioxide and Zinc Oxide. These products must have a very small particle size (nanoparticles) so the packing of the particles reaches the required level, not allowing UVB radiation with a short wavelength to pass.
Personalised sunscreen recipe.
In conclusion, today we know that a good protection is a broad spectrum protection, combined with a stimulating action of the natural biological protection and substances that will neutralise the propagation of the free radicals generated. Further, we should not consider it in a linear way, but rather adapt it to each individual and moment.
We should be studying, in each case, what kind of sun protection we need. We should change it depending on the time of year, the time we go out in sunlight and the exposed areas, the possible exposure to blue and infrared radiation,… The best method would mean melanin stimulation, but it might not always be possible to achieve the level needed and it would have different implications to skin tone.
But today, that is not a problem. We have many alternatives that allow for the design of products for every occasion. The most important aspect is having a personalised “sunscreen recipe”, taking into account our skin´s phototype, our habits, the exposure to inside lighting, the place we live and the time of year. It should also include sound advice on moderating sun exposure and correct application, as well as using the correct product type for each moment.