SkincareSafety Guide

Skin

Understand your skin type, tone, and what your skin is doing.

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Start here

Skin typesThe main skin types and how they differ.Find your skin typeA practical identification guide.What different skin types look likeVisual differences between common skin types.

Common skin questions

Oily skinWhat oily skin means and how to read it.Skin type changesHow skin type can shift over time.Skin type and ageHow visible aging differs by skin type.
Not sure where to start?Use the skin-type guide before choosing routines or ingredients.

Concerns

Start from a skin problem or visible change.

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Oil and acne

Why oily skin happensThe main drivers behind excess oil.Oily skin and acneHow oil can contribute to breakouts.Can oily skin cause acne?A direct answer to the oil-acne link.

Changes and warning signs

Stress and oily skinHow stress may affect oiliness.Dehydration and oilinessWhy skin can feel oily and dehydrated.Skin cancer signsVisual signs that need professional attention.
Looking for a solution?Start with what oily skin actually needs before adding stronger products.

Ingredients

Understand what ingredients do and whether they fit your skin.

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Explore ingredients

NiacinamideA practical ingredient overview.Vitamin C serumWho can use vitamin C and when to be careful.RetinolHow retinol fits different skin types.

Use safely

Salicylic acidWhere this acne-focused ingredient fits.Niacinamide for all skin typesSuitability across skin types.Ingredient comparisonsUse comparisons to avoid mismatched decisions.
Can my skin use this?Browse compatibility questions before adding a new active.

Routines

Turn skin information into daily decisions.

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Daily basics

Does every skin type need moisturizer?A basic routine decision.Does every skin type need sunscreen?Where SPF fits in daily care.What oily skin needsA simple care direction for oily skin.

Adjust over time

Skin changes with ageWhen your routine may need to change.Seasonal skin changesHow weather affects skin behavior.Korean skincare approachWhat is useful beneath the trend.
Starting from scratch?Begin with moisturizer, sunscreen, and one skin-specific need.

Products

A small selection of skincare products recommended by OuterDerm for simple, effective everyday routines.

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Recommended picks

Daily SunscreenDaily UV protection that has to be wearable enough to stick with.Azelaic AcidA focused 10% azelaic acid when uneven tone or blemish marks are the concern.Gentle CleanserComfortable cleansing when tight or squeaky skin is a warning sign.
Not sure where to start?Browse three carefully selected essentials, then ask on WhatsApp before you order.

Learn

Go deeper into skin science, myths, evidence, and safety.

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Hazardous ingredients

Safety hubStart with mercury, steroids, PPD and other hazardous substances.Ingredient safety indexBrowse Phase 1 and Phase 2 hazardous ingredients.Mercury in whitening creamsLabel names, Punjab alerts, and what to do now.

Product literacy

Product literacy hubHow to read labels, claims, and INCI lists before you buy.How to read an ingredient labelINCI order, Parfum, and missing-list red flags.Fragrance-free vs unscentedHow to verify a fragrance-free claim on the ingredient list.How to choose sunscreenBroad spectrum, wearability, and a readable pack — not a fairness claim.

Skin science

Skin color geneticsHow inherited traits shape skin color.Skin color typesHow skin tone is commonly grouped.Are skin types genetic?What genetics can and cannot explain.

Evidence and myths

Can all skin types tan?Tanning, risk, and skin type.Is oily skin good or bad?A balanced view of oily skin.Why Korean skin looks flawlessTrend claims translated into practical basics.
Want the evidence layer?Use why-guides when you want causes, mechanisms, and context.

Skin Pigmentation Disorders

What Is Melasma on Skin?

Melasma doesn't just change the color of your skin - it changes how you feel about it. Those patches of darker skin are a sign that your skin's pigment-producing cells have gone into overdrive, and understanding why is key to knowing what to do about it.

Quick answerMelasma on the skin is an acquired hyperpigmentation disorder caused by overactive melanocytes producing excess melanin.

Medically reviewed by Dermatology reviewer · Updated Jul 19, 2026 · 8 min read

Close-up of skin showing melasma patches with varying shades of brown
Affected Skin LayerEpidermis (surface) and/or dermis (deeper)
Pigment TypeExcess melanin production
Common LocationsFace, forearms, neck, décolletage
Skin Tone ImpactMore common in skin types III-V
Physical SensationNone - no itching, pain, or flaking

Key answer

A common pigmentary disorder

Melasma on skin is a benign condition caused by overactive pigment cells producing excess melanin. It's triggered by sun and hormones, and can be managed with proper care and treatment.

Evidence
Strong - A common pigmentary disorder
Best for
Anyone with skin discoloration wondering about melasma; People looking to understand the science behind their pigmentation
Limitation
Those seeking self-diagnosis without professional consultation

See what the evidence shows

Short version

Story in brief

To understand melasma, you need to understand melanin - the pigment that gives skin its color. Melanin is produced by cells called melanocytes, which are scattered throughout the skin's layers. When everything is working normally, melanocytes produce just enough melanin to match your skin's natural color and respond appropriately to UV exposure.

In melasma, something goes wrong with this system. The melanocytes become hyperactive, producing melanin in excess and depositing it in the skin. This can happen in response to UV radiation, hormonal signals (especially estrogen and progesterone), or sometimes for reasons we don't fully understand. The result is patches of skin that are noticeably darker than the surrounding areas.

The pigment can accumulate in different layers of the skin. When it's in the epidermis (the surface layer), it appears brown and tends to respond better to treatment. When it's deeper, in the dermis, it appears more grayish or blue-brown and is more stubborn. In many cases, it's a combination of both, which is why melasma can be so challenging to treat.

Mental model

Visual explanation

Evidence

What the evidence shows

The depth of pigment in the skin is one of the most important factors in melasma - epidermal pigment is more responsive to treatment, while dermal pigment is more stubborn and may require a different approach. Understanding this helps explain why some people see results from creams while others don't.

  • Is the pigment brown or gray-brown?

    Brown pigment is usually epidermal (more treatable), while gray-brown suggests deeper pigment.

  • Did it appear with sun exposure or hormones?

    This is classic for melasma and confirms the likely diagnosis.

  • Are there other symptoms like itching or flaking?

    Melasma doesn't cause these symptoms - their presence suggests another condition.

Use this section to decide

Does this advice apply to me?

Find the concern or goal closest to yours, then use the fit signal to decide how much weight to give this guide.
Strong fit means the advice is central to that goal.Depends means formula, tolerance, or context matters more.Use caution means do not treat it as the main answer.

  • If your goal is

    What it isUse caution
    Fit signal
    Limited evidence

    Excess melanin production

  • If your goal is

    Skin layers affectedUse caution
    Fit signal
    Limited evidence

    Epidermis and/or dermis

  • If your goal is

    Key triggersDepends
    Fit signal
    Possible fit

    UV, hormones, heat

  • If your goal is

    Is it dangerous?Usually relevant
    Fit signal
    Often useful

    No

  • If your goal is

    Is it treatable?Usually relevant
    Fit signal
    Often useful

    Yes, with consistent care

Research notes already in this guide

  • UV radiation is the primary environmental trigger, with research showing a clear dose-response relationship.
  • Hormonal influences are established, with estrogen and progesterone receptors present on melanocytes.
  • Recent research has identified vascular endothelial growth factor (VEGF) and inflammatory mediators in melasma-affected skin.
  • Genetic predisposition is significant, with family history present in many cases.
  • Treatment studies demonstrate that combination therapy works better than monotherapy for most patients.

Explanation

How it works

  1. Trigger activation

    UV radiation, hormones, or heat activate melanocyte-stimulating pathways in the skin.

  2. Melanocyte response

    Melanocytes begin producing more melanin and transfer it to surrounding skin cells.

  3. Melanin accumulation

    Excess melanin accumulates in the epidermis and/or dermis.

  4. Visible hyperpigmentation

    The accumulated melanin appears as brown or gray-brown patches on the skin surface.

Practical use

How to use it

  1. Get an accurate diagnosis

    A dermatologist can confirm whether your skin changes are melasma and determine the depth of pigment using a Wood's lamp examination.

  2. Begin rigorous sun protection

    Use broad-spectrum SPF 50+ daily on affected and unaffected skin, wear protective clothing, and minimize sun exposure.

  3. Discuss treatment options

    Treatment may include topical creams, chemical peels, or laser therapy. Combination approaches usually work best.

Safety

Side effects and cautions

  • Believing melasma is just a surface-level issue

    Melasma involves pigment in deeper skin layers, which is why surface treatments alone often don't work.

  • Assuming all brown patches on skin are melasma

    Many conditions cause skin darkening - accurate diagnosis by a dermatologist is essential.

  • Expecting topical creams to work without sun protection

    Sun exposure triggers the melanocyte activity that drives melasma - treatments can't overcome continued exposure.

Fit

Who should be careful

  • Those seeking self-diagnosis without professional consultation

Helpful context

What else is worth knowing

Who Should Read This

Is this guide for you?

You have unexplained dark patches on your skin

Learn whether melasma could be the cause and what to do about it.

You've tried to fade hyperpigmentation without success

Understanding the skin biology helps explain why some treatments work and others don't.

You're concerned about skin cancer

Melasma is benign, but any new or changing skin lesion should be evaluated by a professional.

Worth noting

Small details that can change the answer

  • Epidermal vs Dermal. Melasma can be epidermal (pigment in the surface layer), dermal (deeper layer), or mixed.
  • Melanocyte Activity. The condition is driven by overactive melanocytes, not by an increased number of them.
  • Inflammatory Component. Recent research shows melasma-affected skin has more inflammatory cells and blood vessels than normal skin.
  • Benign Nature. Melasma is not cancerous and doesn't increase skin cancer risk.

Melasma on skin is an acquired hyperpigmentation disorder caused by overactive melanocytes.

The pigment can be in the epidermis (surface), dermis (deeper), or both, affecting treatment response.

Sun exposure and hormones are the primary triggers, and strict sun protection is essential for management.

Melasma is benign - it doesn't affect health or increase cancer risk.

Treatment is possible but requires patience and a comprehensive approach combining protection and active treatments.

Definition

What melasma looks like on the skin

Melasma presents as flat, well-defined patches of hyperpigmentation. The color can range from light brown to dark brown, and some patches may have a grayish or gray-brown hue. The patches have irregular borders that are usually distinct from the surrounding skin. They don't have any texture changes - the skin surface feels normal, just darker. The condition most commonly affects sun-exposed areas, particularly the face, but can also appear on the forearms, neck, and décolletage.

  • Patches are flat, not raised or textured
  • No associated flaking, scaling, or skin surface changes
  • Color ranges from tan to dark brown or gray-brown
  • Borders are distinct but can be irregular
  • No physical symptoms like itching, pain, or burning

Science

The science of pigment production in melasma

The skin's pigment system is remarkably complex. Melanocytes produce melanin inside specialized organelles called melanosomes. These melanosomes are then transferred to keratinocytes, the main cells of the outer skin layer, where they accumulate and contribute to skin color. In melasma, several things go wrong. Melanocytes become hyperactive, producing more melanin than necessary. They also transfer more melanosomes to keratinocytes, and the melanosomes themselves may be larger and darker than normal. The result is visible darkening of the skin.

Melanocyte
A pigment-producing cell in the skin's basal layer that produces melanin.
Melanosome
An organelle inside melanocytes where melanin is produced and stored.
Keratinocyte
The most common cell type in the epidermis, which receives melanin from melanocytes.
UV-induced melanogenesis
The process by which UV radiation triggers melanin production as a protective response.

Risks

Factors that increase risk of melasma on skin

While anyone can develop melasma, certain factors significantly increase the likelihood of developing this pigmentation disorder.

  • Being female - women represent about 90% of cases
  • Pregnancy - hormonal changes trigger melanocyte activity
  • Oral contraceptives and hormone therapy
  • Fitzpatrick skin types III-V (medium to dark skin)
  • High cumulative sun exposure
  • Family history of melasma
  • Exposure to heat sources (saunas, hot weather, cooking heat)

Questions

Frequently asked questions

Can melasma affect any skin type?

Yes, but it's more common and more noticeable in skin types III-V (medium to dark skin).

Does melasma get worse with heat?

Yes, heat can trigger melanocyte activity and worsen melasma. This includes saunas, hot weather, and cooking heat.

Is melasma permanent?

Melasma can be persistent and chronic, but it's not necessarily permanent. With consistent treatment and sun protection, significant improvement is possible.

Can melasma appear suddenly?

Melasma usually develops gradually, but it can appear more suddenly with significant hormonal changes like pregnancy or starting birth control.

References

Sources

The notes below are drawn from the evidence already cited in this guide. They are not a complete bibliography.

  1. UV radiation is the primary environmental trigger, with research showing a clear dose-response relationship.
  2. Hormonal influences are established, with estrogen and progesterone receptors present on melanocytes.
  3. Recent research has identified vascular endothelial growth factor (VEGF) and inflammatory mediators in melasma-affected skin.
  4. Genetic predisposition is significant, with family history present in many cases.
  5. Treatment studies demonstrate that combination therapy works better than monotherapy for most patients.