But be careful: as the skin, the hair is also subject to sun damage.
This has always been an interesting topic and taken to heart by the formulators of cosmetic products and the progress of science, combined with studies on the actions of the sun, have led to having products that are increasingly performing and safe for our health.
We will see below what are the damages caused by the sun on our hair and we will try to explain them thoroughly.
SUN AND HAIR: KNOW TO PREVENT.
As we have already seen, the hair is made up of three sections: bark, which resides inside the fiber, the cuticle, made up of scales that form the outer protective layer and finally the marrow that lies between the cuticle and the cortex.
The main causes of dryness, porosity and color loss of our hair are two of the three radiations emitted by the sun: UVA and UVB (note: UVC are blocked at the level of the atmosphere by the ozone layer).
From the studies carried out, researchers have shown that the damage of UVA and UVB is determined by the production of free radicals, highly reactive chemical species ready to interact with proteins and amino acids present in the hair. This loss of structural solidity favors the onset of other mechanical and physical alterations; all this leads to dull, fragile and ruined hair.
UVBs are responsible for the most serious damage due to their greater penetration capacity compared to UVA. Their wavelengths, ranging from 280 nm to 320 nm, interact with chromophoric amino acids (amino acids able to absorb radiation such as cysteine, tyrosine, phenylalanine, and tryptophan) causing the degradation of keratin and melanin.
Electron microscope studies have also shown the disruption of disulfide bonds, chemical bonds between keratin fibers.
These structural changes lead to a lower capacity of the hair to resist chemical treatments (permanent /dyeing/bleaching) or mechanical (brushes and phonation) up to a loss of traction force and a depletion of the fiber that even with the naked eye it appears more porous, irregular and less glossy.
UVAs are responsible for the significant and perceptible loss of color as they induce photo-oxidation reactions inside the cuticle. They have a lower penetration capacity (320 – 400 nm) and are responsible for the degradation of the color absorbed during the permanent coloring processes.
Over the years there have been several approaches to increase prevention and protection of hair from UVA and UVB radiation.
These treatments use both natural extracts and substances of synthetic derivation.
An excellent ally against color loss is the extract of Punica gratatum L. (more commonly known as pomegranate extract) which prevents the oxidation of melanin by up to 60%. This is because the pomegranate contains high amounts of polyphenols that act as antioxidants that can counteract the free radicals produced by UV rays, preventing capillary aging.
Hydrolyzed proteins (Hydrolyzed Protein) are also useful for repairing fibers damaged by free radicals because they bind to the surface of the damaged hair giving it a greater tensile capacity and increasing its tensile strength.
Finally, we would like to mention sunscreens, a category of substances that can be of synthetic origin (Ethylhexyl methoxycinnamate, Polyamide-2 are some of these) or mineral (such as titanium dioxide or zinc oxide). They are deposited on the surface of the hair and act as a “scavenger” (substrates) absorbing or reflecting solar radiation depending on the structure of the molecule.
One last important tip: read the label carefully.
The formulation must include a system of high coverage filters that covers both the spectrum of UVA and UVB radiations in this way you only have to worry about the choice of your goals…of your hair health, we will take care of it!