Pigmentation Pathways & Behaviour Patterns
Why Pigment Moves, Darkens, Spreads or Returns — The 5 Pathways
UV / HEAT-Triggered Pigment Pathway
Driven by:
- UV light
- infrared heat
- sunlight
- strong studio lighting
- hot weather
- hot yoga / saunas
Biology:
- heat and UV activate melanocyte factories
- tyrosinase rises
- melanin production increases
- pigment becomes deeper and darker
Why it’s hard to control:
- melanocytes “remember” past heat exposure
- each heat event can darken existing patches
Inflammation Pathway (PIH)
Triggered by:
- acne
- picking
- irritation
- eczema
- friction
- sensitivity
- barrier breakdown
- harsh skincare
Biology:
- inflammation sends a danger signal
- immune cells activate melanocytes
- pigment forms as a “shield”
- darker in medium–deep skin
PIH is the most common pigmentation in the UK and the most misunderstood.
Hormonal Pathway (Melasma / HPA Axis Activation)
Triggered by:
- pregnancy
- contraception
- progesterone
- oestrogen fluctuations
- perimenopause
- HRT
- stress hormones (cortisol surge)
Biology:
- hormones directly activate the MITF gene
- melanocytes become hypersensitive
- pigment becomes symmetrical (classic melasma pattern)
- worsens with heat AND light
This is the hardest pigment type to control — but Aeternitas approaches it scientifically.
Metabolic / Stress Pathway
Triggered by:
- high cortisol
- inflammation
- poor sleep
- stress-driven immune activation
Biology:
- stress increases inflammatory messengers
- these messengers activate melanocytes
- pigment darkens under emotional pressure
Clients often say:
“My pigmentation gets worse when I’m stressed.”
This is biologically correct.
Vascular–Pigment Interaction Pathway (Red–Brown Mix)
Triggered by:
- chronic redness
- inflammation
- microvascular fragility
- hormonal flushing
- rosacea-type behaviour
Biology:
- redness increases heat
- heat activates melanocytes
- inflammation deepens pigment
- vascular activity makes pigment look darker
This is why:
- lighter skin sees red–brown patches
- deeper skin sees brown–purple patches
ETHNICITY AND PIGMENT BIOLOGY
FITZPATRICK I–III
- more pheomelanin
- more freckling
- more UV damage
- more vascular–pigment interaction
- slower deep pigment formation
- faster superficial pigment formation
FITZPATRICK IV–VI
- more eumelanin
- deeper melanin reservoirs
- higher PIH risk
- more reactive melanocytes
- darker pigment response to inflammation
- melasma more intense
- heat worsens pigment dramatically
The treatment approach MUST change depending on the skin type.
AGEING AND PIGMENT BEHAVIOUR
With age:
- melanocyte numbers decrease
- the remaining melanocytes overreact
- pigment becomes patchy
- clusters appear
- sun damage becomes brown-grey
- oxidative stress darkens pigment
- skin funnels colour deeper into the dermis
- cell turnover slows → pigment stays longer
This is why pigmentation becomes harder to treat after 35.
HORMONES AND PIGMENT BIOLOGY
OESTROGEN
- increases melanocyte sensitivity
- worsens melasma
- enhances pigment response to heat
PROGESTERONE
- darkens pigmentation
- increases melasma risk
- flares pigment during luteal phase
ANDROGENS
- increase inflammation
- increase oil activity
- trigger PIH from acne
CORTISOL (STRESS HORMONE)
- directly activates melanocytes
- worsens all forms of pigment
- increases inflammation
- slows healing → pigment stays longer
This is why pigmentation often worsens during:
- perimenopause
- pregnancy
- stress
- PCOS
- PMS
- menopause
- medical treatments
HEAT & THE MELANIN–THERMAL RESPONSE
Heat is one of the biggest causes of pigment worsening.
Heat triggers:
- tyrosinase activation
- deeper melanin production
- increased inflammation
- vasodilation → increased melanin transfer
- faster melasma reactivation
- pigment relapse after treatment
Common heat triggers:
- cooking steam
- sun exposure
- hot showers
- heaters
- saunas
- hair dryers
- exercise
- LED misuse in heat-sensitive skins
Understanding heat response is ESSENTIAL to controlling melasma and PIH.
WHY PIGMENTATION LOOKS DARKER IN SOME LIGHTING
This confuses clients more than anything.
Looks darker under:
- bathroom lighting
- warm/yellow light
- car mirrors
- gym lighting
- late-day sunlight
Looks lighter under:
- cool white light
- midday sunlight
- photography lighting
- filtered daylight
Why?
Because melanin absorbs and reflects light differently depending on:
- wavelength
- angle
- depth
- vascular background
- inflammation level
This is NORMAL behaviour — not worsening pigment.
WHY PIGMENTATION MOVES
Pigment doesn’t actually “move.”
But melanocytes can activate in adjacent locations when:
- hormones fluctuate
- inflammation spreads
- heat triggers a wider response
- vascular activity increases
- melanin distribution becomes uneven
Clients are NOT imagining this — pigment patterns often “expand” under biological pressure.
The Art of Scientific Aesthetics
Frequently Asked Questions
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It is a long established fact that a read will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more or less.
It is a long established fact that a read will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more or less.
It is a long established fact that a read will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more or less.
It is a long established fact that a read will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more or less.
