How to choose the best sunscreens for you
Perhaps not everyone knows that sun exposure is good for the heart, as it is able to increase the production of nitroxide, a molecule that dilates blood vessels by reducing pressure. Furthermore, as if they were hormones, the sun's rays: they modulate the activity of the immune system; they stimulate the production of antibacterial substances and vitamin D; they also regulate cell turnover giving relief to those suffering from psoriasis and atopic dermatitis; regulate mood and sleep-wake cycles, with beneficial consequences for the psyche and metabolism. The advantages of the sun, therefore, if you expose yourself correctly, are more numerous than the risks that you run avoiding it.
Sun, radiation and skin: the effects of sunlight
Only UV-B (280-320 nm) and UV-A (320-400 nm) rays, light rays and part of the IR rays reach earth as solar radiation. Our skin reacts with various defensive mechanisms to contact with UV rays, especially with UV-B (Low wavelength) and UV-A (High wavelength) rays. In particular:
- UV-B penetrates the epidermis, causing erythema and subsequent pigmentation after prolonged exposure as well as thickening of the stratum corneum; combined with IR they also induce dehydration; however, they also transform skin cholesterol into vitamin D, a reaction used in heliotherapy to complete the ossification process in children and frail subjects;
- UV-A reaches the dermis where, due to prolonged action, they cause the degeneration of elastic fibers. In the epidermis they cause the oxidation of pre-formed melanin with rapid browning of the skin surface and skin aging. Furthermore, in the presence of any photosensitizing substances present on the skin, spots and skin rashes may also arise.
Sun exposure: let's get to know our skin type
The sun exposure and the resulting tan must be made keeping in mind some fundamental parameters relating to the subject (the "phototype"), the environment (geographical location) and the time (time and duration of the exposure). We always keep in mind that the solar product must be considered as one, but not the only one, instrument of protection against sun damage therefore it is necessary to consider all these parameters and use the necessary precautions.
Dermatologists distinguish the phototypes into five different groups (non-sensitive, insensitive, sensitive, very sensitive and subjects not exposed to UV radiation). The first is that of brown, photoresistant subjects with rapid and uniform pigmentation, MED 45 '(the erythema begins after 45 minutes of exposure); the second one identifies the medium photoresist brown subjects, with progressive and uniform pigmentation, MED 30 '; the third is the slightly photoresistant blond subjects with slow but uniform pigmentation, MED 20 '; the fourth the fawn photoresistant fawn subjects with slow and uneven pigmentation, MED 10 '; the fifth identifies extremely photosensitive subjects, immediate MED. The application of products containing UV filters can allow the extension of the MED reducing the risk of erythema.
Sunscreens: what they are and why solar filters are needed
On each solar product the SPF (Sun Protection Factor) is declared on the label, which indicates the filtering capacity of the product in particular from UVB radiation, and the IP (Protection Index), which represents the photoprotective action towards UVA radiation. The UVA / UVB ratio should also be considered, i.e. if the protective capacity against solar radiation is balanced and, according to current recommendations, the minimum UVA protection must be equal to or greater than 1/3 of the UVB one.
The sunscreens, regulated by Annex V of Law 713/1986 and subsequent amendments, which defines the type and maximum usable concentration, are divided according to the nature and mechanism of action into:
- physical screens: particles of heavy metals that oppose a real screen to UV radiation, through reflection processes and diffusion of harmful radiation, thanks to their capacity. These are mostly used in subjects with fair skin and high sensitivity to light. Zinc oxide and titanium dioxide are the two most used physical shielding agents and, although they have differences in appearance and reflective power, they share some properties, both appearing as odorless white powders. To improve the cosmetic acceptability in the sun product, they are used in a highly micronized condition to allow the transmission of visible light on the one hand and invisible preparation on the skin on the other.
- chemical filters: molecules capable of selectively absorbing UV radiation. These substances are able to capture the photons of UV radiation thanks to their chemical nature, which allows them to interact with certain wavelengths and the fact that these molecules are equipped with double bonds which, by absorbing energy, cause the molecule to take on a different form (isomeric). This energy will then be released again in the form of heat or fluorescence. They include anthranilates, benzophenones, camphor derivatives, cinnamates, dibenzoylmethane derivatives and salicylates. It should be emphasized, on the other hand, that chemical filters also have potentially negative characteristics, including the toxic effects and also the induction of photosensitization phenomena therefore they should not be present in high quantity products.
The solar product: what it is used for and the characteristics it should have
Choosing the right solar is a constant topical problem for the consumer. The cosmetic actions carried out by a sunscreen product are protection against direct damage from UV radiation (erythema, sunburn) and indirect damage (photo-aging). A solar product must filter UV rays and perform this function as effectively as possible, combining a good filtering system with a formulation with optimal performance, allowing the filters to work and stimulating the consumer to repeat applications with ease and comfort.
The formulator has various categories of UVB and UVA filters available, which must be photostable and effective at a low dosage, have a low percutaneous absorption index, be compatible with the ingredients of the formulation, tolerated by the skin, free of photosensitizing and allergenic action. The trend in the field of solar products is to use mixtures of different molecules to cover the entire range of UV rays with small total quantities of filter and achieve optimal synergistic effects. The effectiveness of the filters is linked, among other things, to the frequency of use, therefore it is also conditioned by the convenience of application of the solar product by the consumer.
In addition, an ideal sunscreen product should: have excipients that limit or void the percutaneous absorption of the filters, retaining them in the outer layer of the epidermis, where they must perform their function; be resistant to water and sweat, be photostable and ensure good stability in protective capacity, have good spreadability and high spreadability; be pleasant to use (after-feel and color on the skin); present formulative respect of the claims claimed and contain adjuvants of the protective action (hydration, anti-aging, anti free radicals). A pleasant texture, easy to spread, invisible once applied and, in general, simple to use, is highly sought after.
Which type of solar product is right for you
The choice of the sunscreen product depends on a correct evaluation of the needs and characteristics of the user, therefore it is necessary to consider: on which type of skin (normal, oily, dry) and on which part of the body it will have to perform its function, for which skin type if it is intended for an adult or a child, if it is used for sports.
By skin type: for normal skin you can choose the O / A emulsion, gel emulsion, oil, stick, spray; for oily skin you can choose the O / A emulsion, gel emulsion, spray; for dry skin you can choose the O / A emulsion, A / O emulsion, oil, stick; for children you can choose the A / O and stick emulsion; for the sportsman it is preferable in oil or spray.
The most widespread and versatile type of solar formulations is that of emulsions, in all their forms (hyperfluid, fluid, semi-consistent and consistent): they represent the best cosmetic form to modulate the protection factor, allowing the use of filters physical and chemical and ensuring the formation of a protective film resistant to water and sweat. Highly versatile, they can meet the most diverse needs: you can switch from light and transparent textures, with a dry and quickly absorbed touch, to consistent pastes, suitable for children, with a prevalent base of physical filters.
Some last tips before sun exposure
- Remember that no products for sun protection, even those deemed more effective and which protect both from UVB and UVA are not able to guarantee total protection from the health risks deriving from UV rays. Even if they are not enough on their own, it is good to make abundant use of them as their effectiveness in preventing sunburn and damage to the skin is demonstrated. Apply them every 2-3 hours and after the bath;
- keep in mind that sand, snow and water can reflect up to 85% of the sunlight, intensifying their exposure;
- hydrate well, pay attention to exposure during "critical" hours (from 11 to 15), always expose yourself gradually and progressively;
- infants under 6 months should not be kept in the sunlight and even if in the shade they are better off wearing cotton clothes; for children over two years the "critical" hours are from 10 to 16.
The solar products of Erboristeria Como can be found here.
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