The IR spectrum extends from 780 to 106 nm and decomposes to IRA [780-1480 nm], IRB [1480-3000 nm] and IRC [3-1000 μm] (Figure 3).
Figure 3: Splitting of the infrared spectrum
While sunscreens protect against UV radiation, several studies point out the deleterious impact of infrared and the fact that IR protection should also be added to products [2-4]. Indeed, infrared are involved in skin aging and probably in carcinogenesis ; they are mainly responsible for the increase of skin temperature and lead to the production of free radicals and metalloproteinases-1 (MMP-1) in the dermis [6-8].
Effective protection against infrared can be achieved by adding absorbing optical filters in the IR range, free radical scavengers and / or photon reflection .
Dermscan proposes to evaluate the protective effect of cosmetics against infrared by complementary approaches, after infrared irradiation :
- biometric approach: cutaneous measures of color and/or temperature and/or microcirculation
- biochemical approach: lipid oxidation assays (SQOOH, MDA) and/or enzymes (CAT, SOD)
The spectrum of blue light extends from 380 to 490 nm, passing from violet to indigo then to blue (Figure 4).
Figure 4: Splitting of visible light
Recent studies have shown that this type of light – especially short wavelengths around 415 nm – could lead to erythema, free radical production and long-lasting hyperpigmentation in phototype subjects III and more [11,12].
Current chemical filters are not able to block visible light, and blue light in particular. Only mineral filters can – depending on the size of the particles – filter blue radiation . Another approach is to add anti-oxidants to the cosmetic formulas to limit accelerated skin aging and damage caused by blue light .
Dermscan offers different approaches to evaluate the anti-blue light protective effect at the level of the skin:
- Irradiation (single or repeated) in blue light (peak at 415 nm) followed by evaluation of β-carotene oxidation, protein carbonylation, lipid oxidation or pigmentation.
- test in real conditions, on subjects regularly exposed to the screens of electronic devices: effect on the radiance of the complexion and the cutaneous fatigue.
Do not hesitate to ask us about these topics! We will advise you the protocol that meets your needs.