Hyperpigmentation & Dark Spots

Melanin, the pigment responsible for skin tone and dark spots alike, is produced through a pathway controlled by the enzyme tyrosinase, described in a comprehensive 2019 review as the rate-limiting step in melanin production. UV exposure is the most common trigger, stimulating this pathway and increasing melanin output in localised areas, which is why hyperpigmentation often concentrates on sun-exposed skin.

Because tyrosinase sits at that single rate-limiting step, ingredients that inhibit it (rather than simply exfoliating existing pigment away) address the process closer to its source, which is the basis for most established brightening actives.

Because melanin production is triggered by UV exposure, hyperpigmentation can worsen with continued sun exposure even after a dark spot has already formed, which is why daily SPF is considered a foundational part of any brightening routine rather than an optional add-on. Without consistent sun protection, tyrosinase-inhibiting ingredients are working against an ongoing trigger rather than a settled one.

Hyperpigmentation also varies by depth: some pigment sits in the upper epidermis and can fade relatively quickly with consistent care, while pigment that has settled deeper in the dermis (often the case with marks left by inflammation, like those after a blemish clears) can take considerably longer to visibly improve. That's a normal part of how melanin clears rather than a sign an ingredient isn't working, and is part of why brightening routines are generally measured in months rather than weeks.

Because tyrosinase inhibition works gradually by slowing new pigment production rather than removing existing pigment instantly, pairing it with gentle exfoliation, which can help surface pigment clear a little faster, is a commonly used complementary approach.

In practice, that means pairing a tyrosinase-inhibiting active with daily SPF rather than expecting either on its own to fully address existing dark spots. Protection helps limit new pigment forming while the active works gradually on what's already there.