J6

The question

Why does ordinary daylight darken my marks, even indoors?

What's happening in your skin

Sunlight is about 44% visible light, and unlike UVB, visible light passes through window glass. In melanin-rich skin it triggers a pigment response through light-sensing proteins in the skin. Your sunscreen's SPF number says nothing about it; only pigments in the formula, chiefly iron oxides, block it.

What the research shows

  1. Visible light produced darker and more sustained pigment than UVA1 in skin types IV–VI.

    Mahmoud et al., J Invest Dermatol 2010 (L042)High

  2. An iron-oxide sunscreen improved melasma treatment outcomes versus a UV-only sunscreen with equal SPF.

    Castanedo-Cazares et al., 2014 (L043)High

  3. Tinted iron-oxide sunscreen prevented melasma relapse over a summer better than an untinted twin.

    Polena et al., 2025 (L044)Moderate

  4. 97% of tinted sunscreens don't list iron oxides as actives; 3 of 24 brands disclose concentration.

    Doan et al., JDD 2026 (L045)Moderate

Our answer

If you have dark marks or melasma, visible-light protection matters as much as SPF. Look for iron oxides and ask how much. BluVeil doesn't contain iron oxides.

ActionCheck your current sunscreen's ingredient list for iron oxides.

Which product does this touch?BluVeil SPF 30

Educational only, and not medical advice. Dr. Kita Skincare products are cosmetics. If a skin concern is persistent or painful, see a doctor.

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