Melanogenesis: Understand It and Every Pigment Treatment Makes Sense
The Full Melanin Journey
- Trigger: UV prompts keratinocytes to release α-MSH and other signals — the “overtime order” to melanocytes.
- Synthesis: inside melanocytes, tyrosinase (the rate-limiting enzyme) oxidizes tyrosine through DOPA and dopaquinone into eumelanin (brown-black) and pheomelanin (yellow-red).
- Packaging: melanin loads into melanosomes.
- Transfer: melanosomes travel along dendrites to ~36 surrounding keratinocytes.
- Ascent and shedding: pigmented keratinocytes rise and shed over the ~28-day epidermal cycle.
Where Each Treatment Acts
| Step | Interventions |
|---|---|
| Trigger | Sunscreen (source reduction), niacinamide (transfer + inflammation) |
| Synthesis | Arbutin, kojic acid, tranexamic acid — tyrosinase inhibitors |
| Made melanin | Q-switched/picosecond lasers, IPL shatter it directly |
| Clearance | Retinoids accelerate turnover; peels speed shedding |
Why Combinations Always Win
Sunscreen cuts new orders, topicals inhibit synthesis, devices clear stock, acids speed turnover — four steps, four jobs. Lasers without sunscreen are clearing stock while restocking; that is the logic behind PIH and relapse.
What Skin Types Mean
Fitzpatrick types (I-VI) grade melanocyte activity: from type III up, every light-based treatment assumes PIH risk in parameters and aftercare — a property of the target, not a device flaw.
FAQ
More melanocytes = darker skin?
No — counts are similar across ethnicities; activity, melanosome type and size differ. “Brightening” modulates function, it does not eliminate cells.
What does the 28-day cycle mean for pigment?
Epidermal pigment fades naturally with turnover; anything accelerating turnover (acids, retinoids) speeds improvement — and explains relapse when stopped.