Hat, sunglasses, sun creams... you are undoubtedly aware of the essential need to protect oneself from the harmful effects of the sun. However, with the multitude of choices between chemical and mineral versions, it can be difficult to decide on one or the other. Effectiveness, drawbacks, approach to sun protection, adaptation to your skin type... here is everything you need to know about organic sun filters versus inorganic sun filters.
Chemical or mineral sunscreen: which one should be used for your skin?
Summary
Published on October 4, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 9 min of reading
Themes:
Chemical filter, mineral filter: what about their differences?
To protect the skin from the harmful effects of the sun, both UVB and UVA rays, there are two types of UV filters used in sunscreens: chemical filters and physical filters. Strictly regulated in Europe, only 27 UV filters are authorised by the European cosmetic regulation, all evaluated by the European Scientific Committee for Consumer Safety (SCCS).
Physical filters.
Composed of an assembly of mineral microparticles, these sunscreens with a particle size of 200 to 500 nm are capable of diffracting and reflecting UV rays in the UVB and UVA spectrum and visible light through a mechanical action similar to an opaque barrier, by creating a film of inert metallic particles.
Benefits : More tolerant, they are less allergenic than sun creams containing organic filters and do not cause sensitisation reactions. Indeed, it has been demonstrated that sunscreens using only inorganic filters do not penetrate further than the corneal layer and the upper layers of the epidermis. Moreover, only mineral sun protection products can be labelled as organic. Finally, these molecules are photostable.
Drawbacks : Sunscreens composed of mineral filters tend to leave white traces on the skin during application, due to their opaque nature. However, this white appearance disappears gradually during application. In order to improve these organoleptic characteristics of products formulated with physical filters, a formulation effort has been made: mineral filters now exist in nanoparticle form. However, already banned in spray form, the presence of nanoparticles could potentially cause toxic effects on marine flora, particularly on phytoplankton, not to mention the fact that they could cause a trans-epidermal passage phenomenon resulting in potential toxicity.
Chemical filters.
Composed of chemically modified carbon compounds, these sunscreens create a thin filtering film that directly absorbs solar radiation in place of the skin, due to the presence of a chromophore group. They then transform UV light into fluorescent radiation or dissipate it through internal conversion mechanisms, releasing the energy in the form of a small amount of heat.
Benefits : Being more fluid, they leave less of a "white" effect on the skin for a more even application.
Drawbacks : Due to their mechanism of action, chemical filters can penetrate the skin barrier and thus may induce a minimal risk of allergy (redness, irritation...), especially in individuals with sensitive and atopic skin. Moreover, some UV filters are subject to controversy as they are suspected of acting as endocrine disruptors. However, we lack perspective and studies regarding their potential harm which remains to be proven. The doubts do not concern all chemical filters. In the meantime, it is better to apply the precautionary principle and avoid suspect compounds, such as theoctocrylene, oxybenzone (INCI: Benzophenone-3), thehomosalate, theavobenzone (INCI: Butyl Methoxydibenzoylmethane), the sulisobenzone (INCI: Benzophenone-4), the padimate-O (INCI: Ethylhexyl Dimethyl PABA), the PABA, etc. Finally, some chemical filters could also have an impact on the environment: they would be toxic to marine fauna and corals.
However, whether the cream is mineral or chemical, there is no difference in terms of protection efficacy against UV rays.
| Sunscreen approved by the European Cosmetic Regulation | Maximum concentration allowed by the European cosmetic regulation (%) | Protection Range (nm) | Maximum Absorption Wavelength (nm) | Protection Provided (UVA/UVB) |
|---|---|---|---|---|
| Titanium Dioxide (INCI: Titanium Dioxide) | 25% | 290 - 350 nm | Variable | UVA, UVB |
| Zinc Oxide (INCI: Zinc Oxide) | 25% | 290 - 400 nm | Variable | UVA, UVB |
| Avobenzone (INCI: Butyl Methoxydibenzoylmethane) | 5% | 310 - 400 nm | 358 nm | UVA |
| Diethylamino Hydroxybenzoyl Hexyl Benzoate (INCI: Diethylamino Hydroxybenzoyl Hexyl Benzoate) | 10% | 250 - 400 nm | 354 nm | UVA |
| Octinoxate (INCI: Ethylhexyl Methoxycinnamate) | 10% | 280 - 310 nm | 311 nm | UVB |
| Octisalate (INCI: Ethylhexyl Salicylate) | 5% | 260 - 310 nm | 307 nm | UVB |
| Octocrylene | 10% | 280 - 320 nm | 303 nm | UVB |
| Ensulizole (INCI: Phenylbenzimidazole Sulfonic Acid) | 8% | 290 - 340 nm | 305 nm | UVB |
| Octyl Triazone (INCI: Ethylhexyl Triazone) | 5% | 250 - 340 nm | 314 nm | UVB |
| Homosalate | 7.34% | 295 - 315 nm | 306 nm | UVB |
| Bisimidazylate (INCI: Disodium Phenyl Dibenzimidazole Tetrasulfonate) | 10% | 320 - 350 nm | 335 nm | UVA |
| Ecamsule (INCI: Terephthalylidene Dicamphor Sulphonic Acid) | 10% | 295 - 390 nm | 345 nm | UVA |
| Oxybenzone (INCI: Benzophenone-3) | 6% | 270 - 350 nm | 288, 325 nm | UVA, UVB |
| Anisotriazine (INCI: Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine) | 10% | 280 - 400 nm | 310, 341 nm | UVA, UVB |
| Bisoctrizole (INCI: Methylene Bis-Benzotriazolyl Tetramethylbutylphenol) | 10% | 280 - 400 nm | 306, 360 nm | UVA, UVB |
| Para-aminobenzoic acid (INCI: PABA) | 5% | 260 - 313 nm | 283 nm | UVB |
| Mexoryl XL (INCI: Drometrizole Trisiloxane) | 15% | 280 - 400 nm | 303, 344 nm | UVA, UVB |
| Padimate O (INCI: Ethylhexyl Dimethyl PABA) | 8% | 280 - 320 nm | 311 nm | UVB |
| Diethylhexyl Butamido Triazone | 10% | 280 - 320 nm | 311 nm | UVB |
| Tris-biphenyl triazine | 10% | 280 - 400 nm | 310 nm | UVA, UVB |
| Enzacamene (INCI: 4-Methylbenzylidene Camphor) | 4% | 280 - 320 nm | 305 nm | UVB |
| Amiloxate (INCI: Isoamyl p-Methoxycinnamate) | 10% | 280 - 320 nm | 289 nm | UVB |
| Ethyl-4-aminobenzoate ethoxylate (INCI: PEG-25 PABA) | 10% | 280 - 320 nm | 308 nm | UVB |
| Dimethicodiethylbenzalmalonate (INCI: Polysilicone-15) | 10% | 280 - 320 nm | 313 nm | UVB |
| Sulisobenzone (INCI: Benzophenone-4) | 5% | 250 - 380 nm | 288, 366 nm | UVA, UVB |
| Camphor Benzalkonium Methosulfate (INCI: Camphor Benzalkonium Methosulfate) | 5% | 280 - 320 nm | 295 nm | UVB |
| Mexoryl SL (INCI: Benzylidene Camphor Sulfonic Acid) | 6% | 280 - 400 nm | 295 nm | UVA, UVB |
| Mexoryl SW (INCI: Polyacrylamidomethyl Benzylidene Camphor) | 6% | 280 - 320 nm | 301 nm | UVB |
Discontinued
Chemical filter or mineral filter?
Although infrequent and subjective, tingling, redness, and heat sensations are the most common complaints associated with chemical sunscreens. However, individuals prone to photodermatoses and eczema may be predisposed to developing a photo-allergy. Consequently, reactive, sensitive, or even sun-allergic skin should opt for sunscreens based on mineral filters (zinc oxide and titanium dioxide) as a precaution, as they are generally better tolerated. Delicate and sensitive, sun creams with sun filters are also recommended for children.
Most of the time, a sun protection product combines both filters to cover the entire solar spectrum. Without nanoparticles, our sunscreen products combine mineral filters with chemical filters for reasons of application comfort and texture.
Sources
FERGUSON J. & al. New sunscreens confer improved protection for the photosensitive patients in the blue light region. British Journal of Dermatology (2001).
CORTING H. C. & al. Sunscreens - Which and what for? Skin Pharmacology and Physiology (2005).
NASH J. F. Human safety and efficacy of ultraviolet filters and sunscreens products. Clinics in Dermatology (2006).
BENS G. Sunscreens. Advances in Experimental Medicine and Biology (2014).
