Blue light and skin

Visible light does reach skin and does have effects, and the best-supported of them is pigmentary. Controlled exposure studies show visible light can induce pigmentation that lasts longer than UVA-induced pigmentation, and the effect is far more pronounced in deeper skin tones. That makes it a question about melasma and post-inflammatory hyperpigmentation rather than about wrinkles. Opsin-3, a light-sensitive receptor found in melanocytes, is the mechanism most often proposed for it.

The screen part is where marketing has run ahead of the science. The blue light a phone or laptop emits is a small fraction of what a few minutes outdoors delivers, including under cloud, and the studies used to sell screen-protection skincare generally use lamp intensities and exposure times no consumer device produces. There is no good evidence that ordinary screen use causes measurable skin damage.

• If visible-light pigmentation is your concern, a tinted sunscreen is the practical answer — the iron oxides in the tint absorb visible light, which clear mineral and chemical filters largely do not.
• Antioxidants under sunscreen address the free-radical part of the damage, not the light itself.
• Your laptop is not a reason to buy a product.

The honest summary is that blue light is a real and under-appreciated part of sun exposure, particularly for anyone managing melasma on deeper skin, and an essentially irrelevant part of sitting at a desk. Sun protection that accounts for visible light is worth having. A product sold on the strength of your screen time is not.