In the article for Live Science, Anna Gora explains the freckles are not just "beauty marks" but a functional biological response to solar radiation. These small pigmented spots-scientifically known as ephelides-primarily emerge when the skin is exposed to UV light. The core of this process involves melanocytes, specialized cells that produce melanin. Melanin acts as a natural sunscreen, absorbing UV rays to protect the skin's DNA from damage. In most people, sun exposure leads to an even distribution or melanin resulting in tan. However, in individuals with certain genetic predispositions- specifically variations in the MC1R gene, the melanocytes produce melanin in concentrated "clumps" rather than an even layer. These clusters appear as freckles.

Gora notes that while freckles are common among fair-skinned individuals and redheads, they can occur in people of all skin tones. Crucially, freckles are dynamic; they often darken or multiply during the summer months and fade significantly during the winter when UV exposure decreases. Unlike sunspots or moles, which are permanent or related to aging, ephelides are a temporary, genetically driven protective mechanism triggered by the sun.