Which ingredients should be included in a sunscreen to provide protection against artificial visible and high‑energy visible (HEV) light, such as that emitted by screens?

Protection Against Artificial Screen Light: Iron Oxides and Pigmentary Titanium Dioxide

For protection against visible and high-energy visible (HEV) light from screens, sunscreens must contain iron oxides and pigmentary titanium dioxide in tinted formulations—standard transparent sunscreens with nanoparticle zinc oxide or titanium dioxide do not provide meaningful visible light protection. 1

Why Standard Sunscreens Fail Against Screen Light

• Broad-spectrum sunscreens protect effectively against UV radiation but do not adequately protect against visible light, including the blue light emitted by electronic screens. 1
• Modern mineral sunscreens use zinc oxide and titanium dioxide as nanoparticles (50–150 nm) specifically to minimize the chalky white appearance on skin; this transparency means they cannot block visible light. 1, 2
• For a sunscreen to protect against visible light wavelengths, it must be visible on the skin—the product must contain pigments that absorb or reflect light in the visible spectrum. 1

Required Active Ingredients for Visible Light Protection

Iron oxides are the primary active ingredients that provide protection against visible and HEV light:

• Tinted sunscreens use different formulations and concentrations of iron oxides combined with pigmentary titanium dioxide (larger particle size than nanoparticles) to provide visible light protection. 1
• Multiple shades are available by varying the amounts and ratios of iron oxides and pigmentary titanium dioxide to match different skin phototypes. 1

Pigmentary titanium dioxide (distinct from nanoparticle titanium dioxide):

• At wavelengths above the semiconductor band gap absorption energy levels—specifically in the long UVA and visible wavelengths—titanium dioxide becomes predominantly reflective (up to 60% reflection) rather than absorptive. 3
• Pigmentary-grade titanium dioxide particles are larger than the 50–150 nm nanoparticles used in transparent sunscreens, allowing them to scatter and reflect visible light effectively. 1

Mechanism of Visible Light Protection

• Visible light induces erythema in light-skinned individuals and pigmentation in darker-skinned individuals, making protection clinically relevant beyond just screen exposure. 1
• Iron oxides and pigmentary titanium dioxide work by absorbing and reflecting photons in the visible spectrum (approximately 400–700 nm), which includes the blue light range (400–500 nm) emitted by screens. 1
• The tint itself is the protective mechanism—the colored pigments physically block visible wavelengths from reaching the skin. 1

Clinical Applications and Target Populations

• Tinted sunscreens are particularly beneficial for patients with visible light-induced photodermatoses and those with hyperpigmentation disorders such as melasma and postinflammatory hyperpigmentation. 1
• For individuals concerned specifically about screen light exposure, tinted formulations containing iron oxides provide the only evidence-based topical protection. 1

Critical Formulation Requirements

• The sunscreen must maintain the standard 2 mg/cm² film thickness to achieve both UV and visible light protection; under-application reduces efficacy across all wavelengths. 2
• Tinted formulations should still contain adequate concentrations of UV filters (zinc oxide and/or titanium dioxide at 5–25%) to provide comprehensive broad-spectrum protection alongside the visible light protection from iron oxides. 2
• The formulation must include polymeric or emollient dispersions to prevent aggregation of both the UV-filtering particles and the iron oxide pigments, ensuring uniform film formation and consistent protection. 4

Common Pitfalls to Avoid

• Do not assume that any sunscreen containing titanium dioxide or zinc oxide provides visible light protection—only tinted formulations with iron oxides and pigmentary-grade (not nanoparticle) titanium dioxide are effective. 1
• Do not rely on transparent "blue light protection" claims without verifying the presence of iron oxides or visible tint; if the product is invisible on skin, it cannot block visible wavelengths. 1
• Do not use powdered makeup containing titanium dioxide as a substitute—these products lack adequate concentration, proper film thickness, and optimized formulation design to provide meaningful photoprotection against either UV or visible light. 2