A sharp rise in skin cancer incidence is colliding with online misinformation that claims sunscreens are toxic, prompting dermatologists in Canada to issue an unequivocal rebuttal. Melanoma Canada reports a 17% increase in diagnoses between 2023 and 2024, with one in five Canadians now expected to develop a skin cancer in their lifetime. At the same time, sleep specialists in Spain are drawing attention to the opposite end of the light spectrum: the habit of sleeping with a lamp or screen on, which they say suppresses melatonin and fragments rest. Viewed together, the interventions describe a single physiological challenge—managing the timing, intensity, and type of light that reaches the body.

The mechanism in both cases centres on wavelength-specific biological disruption. Ultraviolet B radiation is directly carcinogenic to skin cells, while UVA penetrates more deeply and accelerates ageing; both contribute to cataract formation and pterygium growth on the eye, as ophthalmologists at Johns Hopkins and the American Academy of Ophthalmology note. At night, even low-intensity artificial light—filtered through closed eyelids—confuses the suprachiasmatic nucleus in the hypothalamus, inhibiting melatonin secretion. María José Martínez Madrid of the Spanish Sleep Society explains that this leaves sleep shallow and fragmented, with long-term consequences that observational studies link to metabolic, cardiovascular, and neurodegenerative disease.

On the protection side, the consensus from Quebec City to Lund is that sunscreens are safe when used as directed, but application habits undermine their effectiveness. Ivan Litvinov of McGill University and Joël Claveau of CHU de Québec-Université Laval stress that most people apply only a quarter of the necessary quantity and treat sunscreen as a licence to prolong exposure—a phenomenon Litvinov calls the sunscreen paradox. They recommend a sun protection factor of 30 to 50, broad-spectrum coverage against UVA and UVB, and reapplication every two to three hours. Physical blockers containing zinc oxide or titanium dioxide are preferred for sensitive skin and avoid the environmental concerns associated with some organic filters, though they leave a white cast that tinted formulations can offset.

A separate warning comes from aerosol science. Jakob Löndahl, a professor at Lund University in Sweden, cautions that sunscreen sprays generate inhalable particles of titanium dioxide and zinc oxide—substances classified as possibly carcinogenic when deposited in the lungs. Children are especially vulnerable because their airways are still developing. Löndahl advises applying spray at close range to the skin, outdoors, and never directly onto the face; cream formulations eliminate the inhalation risk entirely. For the eyes, ophthalmologists in the United States note that most modern prescription lenses already incorporate UV-blocking polycarbonate or coatings, but sunglasses with tinted lenses reduce visible glare and the squinting that contributes to wrinkles and eye strain.

The next milestone is behavioural rather than regulatory: public health agencies are refining messaging to counter both sun-protection complacency and the spread of unfounded chemical-safety claims. The Canadian Dermatology Association’s approval logo and the encircled UVA symbol on European and Canadian products remain the most reliable consumer shortcuts. Meanwhile, sleep researchers in Spain recommend total darkness for sleep, with low-intensity torches for unavoidable nighttime movement, as the simplest intervention to safeguard circadian integrity.