It’s time to go back to the beach or the pool, for this it is important to find a good sunscreen that protects our skin from the effects of the sun.

In a previous post we saw the effects that the sun has on our skin, so it is essential to protect it using protectors with suitable sunscreens, but do you know the sunscreen that best suits your skin?

Types of sun filters

The filters present in solar formulations can be classified into 3 groups depending on their origin and mode of action [1].


Physical filters produce what is known as a screen effect as they reflect the entire spectrum of solar radiation: ultraviolet, infrared and visible.

The most widely used physical filters are of mineral origin, specifically titanium dioxide and zinc oxide, which are most effective when used in combination in a sunscreen.

These filters are the most effective, however, there is some controversy regarding the particle size of these filters in their cosmetic formulation. When the size of the particle is high, it leaves a whitish layer on the skin, which is why in some formulations it has been decided to reduce the size of these filters to the level of nanoparticles.

The increasingly widespread use of nanoparticles in formulations has required a greater number of studies on their possible side effects. However, the Scientific Committee on Consumer Safety of the European Union approves the use of nanoparticles in sunscreens at concentrations of up to 25%, considering it safe when applied to healthy and burned skin, since they do not penetrate the skin.


Chemical sunscreens, unlike physical ones, do not reflect solar radiation but penetrate the skin to absorb ultraviolet radiation and convert it into heat.

Depending on the type of wavelength of solar radiation that they absorb, we can talk about UVB, UVA or broad-spectrum filters. Chemical filters usually combine ingredients such as oxybenzone, octinoxate/ethylhexyl methoxycinnamate, homosalate, octisalate or octocrylene, molecules made up of carbon, oxygen and hydrogen.

To maximize the action of these sunscreens, the ideal is to apply it half an hour before sun exposure, to allow the protector to be absorbed by the skin.


Unlike physical or chemical filters, they do not block solar radiation. If not, they are antioxidant molecules that prevent the formation of free radicals and help boost the skin’s immune system.

Biological filters are mainly composed of vitamins A, C and E, since these have antioxidant activity by reducing free radicals that are produced by oxidative stress in sun exposure, which allows reducing the effects of photoaging.

 These biological sunscreens are often combined with chemical filters to provide more complete sun protection.

What should a good sunscreen have?

Be safe (non-toxic or allergenic), be stable to high temperatures, changes in pH and exposure to light. In addition, they must be effective in absorbing UVA and UVB radiation. In this sense, the American association against cancer recommends sunscreens with at least factor 30 (SPF 30).

The higher the SPF number, the greater the protection. Thus, sunscreens with SPF 15 filter about 93% of UVB rays, while sunscreens with SPF 30 filter about 97% and those with SPF 50 filter about 98. In other words, no sunscreen provides adequate protection. total but, according to the FDA (American Food and Drug Administration), sunscreens with a factor lower than SPF 15 only protect against sunburn, but not against the development of skin cancer due to sun exposure.

Image by chezbeate from Pixabay

What is the filter that best suits my skin?·     

  • Sensitive skin: The use of chemical filters is not recommended as they can irritate sensitive skin or even cause allergic reactions.
  • Children: The use of physical sunscreens is recommended, as they reflect all solar radiation. These physical filters must contain a maximum of 25% nanoparticles to comply with European recommendations regarding the use of nanoparticles in cosmetic products.
  • All skin types: In general, the use of any type of sunscreen is recommended, but one that produces greater protection than SPF 15. To avoid the effects of solar radiation in the short term (sunburn) and long term (photoaging and possible development of skin cancer).

In any case, it is recommended to use sunscreens with high SPF graduation that filter the highest percentage of solar radiation to protect our skin during the summer.