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 Conditions

Why Does Melasma Happen?

Melasma is a pigmentation puzzle. It's not a single event but a process triggered by a cascade of internal and external signals, leading to a common but often misunderstood skin condition.

Skin, in its daily battle against the sun, has one primary weapon: melanin. It's a brilliant system.

But in melasma, that brilliant system becomes a little too enthusiastic, turning a protective mechanism into a cosmetic challenge.

So how does a well-intentioned security system go rogue?

Imagine a car alarm that's triggered not just by a break-in, but also by a gentle breeze or a passing cat. That's melasma: an overreaction of the skin's alarm system to normal stimuli like sunlight and hormonal changes.

Quick answerMelasma happens when the melanocytes, which are the cells in your skin responsible for producing pigment (melanin), become overactive.

Medically reviewed by Dermatology reviewer · Updated Jul 19, 2026 · 6 min read

A woman with melasma patches on her cheek and forehead
It's a Pigment DisorderCaused by overproduction of melanin
Primary CausesSun exposure, hormones, genetics
Common LocationFace (cheeks, forehead, upper lip)
More Common inWomen, especially during reproductive years
Chronic NatureCan be recurrent and requires ongoing management

Key answer

Well understood

Melasma is a complex condition that happens when a genetic susceptibility meets an environmental trigger (UV light) and a hormonal catalyst. It's a condition of overreaction, not a disease of malfunction.

Evidence
Strong - Well understood
Best for
Those newly diagnosed with melasma who want to understand the root causes; Women who are pregnant or on birth control and noticing pigment changes; People with a family history of melasma looking for a preventative understanding

See what the evidence shows

Short version

Story in brief

Melasma happens when the delicate balance of pigment production in the skin is thrown off. The story begins with the melanocyte, a cell whose job it is to produce melanin, the pigment that gives your skin color and protects it from UV damage. For various reasons, this process can get stuck in overdrive.

The primary drivers of this overdrive are UV radiation, which directly stimulates the melanocytes, and hormones like estrogen and progesterone, which make these cells more sensitive to that stimulation. When these two factors combine, the melanocytes start producing melanin at an excessive rate. This is especially true for people with a genetic predisposition, whose melanocytes are already primed to overreact.

The result is that excess melanin is deposited into the skin, creating the characteristic patches. This isn't a random occurrence; it's a clear, albeit complex, biological response to specific triggers. Understanding this process is the key to understanding why melasma happens and what can be done to manage it.

Mental model

Visual explanation

Evidence

What the evidence shows

Melasma is not a disease of the skin in the classic sense, but rather a hyper-reaction of the skin's pigmentary system to normal, everyday triggers that are amplified by hormonal and genetic factors. It's a matter of degree, not a malfunction.

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

    Primary TriggerDepends
    Fit signal
    Possible fit

    UV Light

  • If your goal is

    CatalystDepends
    Fit signal
    Possible fit

    Hormones

  • If your goal is

    PredispositionUse caution
    Fit signal
    Limited evidence

    Genetics

  • If your goal is

    The Core EventUse caution
    Fit signal
    Limited evidence

    Melanocyte Overactivity

Research notes already in this guide

  • The vast majority of melasma cases occur in women, with a significant onset during pregnancy or with hormonal contraception.
  • Melasma almost always involves sun-exposed areas, with symptoms worsening after sun exposure.
  • A first-degree relative with melasma is a well-established risk factor.
  • Biopsies of melasma lesions show increased melanin in the epidermis and/or dermis, confirming the overproduction.

Explanation

How it works

  1. Step 1: The Trigger

    UV light or hormones signal the melanocyte. This is the "on" switch.

  2. Step 2: The Activation

    The melanocyte starts producing melanin, but at an accelerated rate due to the hormonal influence.

  3. Step 3: The Overproduction

    More melanin is produced than is needed for normal skin color and UV protection.

  4. Step 4: The Deposit

    This excess melanin is deposited into the surrounding skin cells, creating the visible dark patches.

Practical use

How to use it

  1. Commit to Daily Sun Protection

    Apply a broad-spectrum sunscreen of SPF 30 or higher every morning, and reapply throughout the day. Consider a sunscreen with iron oxides for added protection against visible light.

  2. Consult a Dermatologist Early

    A dermatologist can properly diagnose melasma and recommend the most effective treatment plan, which may include a prescription cream or an in-office procedure.

  3. Be Patient and Consistent

    Melasma is notoriously stubborn. Improvement takes time and requires unwavering adherence to a management plan. Don't expect overnight results.

Safety

Side effects and cautions

  • Assuming it's just a tan that will fade

    Melasma is not a tan; it's a patterned hyperpigmentation that is often persistent and requires active management to fade.

  • Using DIY lemon juice or harsh scrubs to lighten it

    These can cause severe irritation, post-inflammatory hyperpigmentation, and may worsen the condition.

  • Thinking you only need sunscreen on sunny days

    UVA rays are present every day and can trigger melasma even through windows or on overcast days. Daily, year-round SPF is non-negotiable.

  • Hyperpigmented patches

    Universal · This is the primary symptom. A dermatologist can help with treatment to fade them.

  • Cosmetic concern and emotional distress

    Common · Melasma can be a source of significant self-consciousness. It's a real, medically recognized condition.

  • Recurrence after treatment

    Occasional · This is why ongoing sun protection and maintenance are critical for long-term management.

Worth noting

Small details that can change the answer

  • It's Not a One-Time Event. Melasma is often a chronic condition that can recur after fading, particularly with renewed sun exposure or hormonal shifts.
  • Hormones Are a Key Driver. The hormonal component explains why it's so much more common in women; fluctuations in estrogen and progesterone directly influence melanocyte activity.
  • Genetics Set the Stage. Your genetics determine your baseline risk. If you have a family history of melasma, your melanocytes are likely more reactive to triggers.
  • Visible Light Matters Too. Recent research shows that visible light (HEV blue light) from screens and the sun can also trigger melasma, particularly in darker skin types.

Melasma happens when pigment-producing cells (melanocytes) become overactive.

The primary triggers are UV exposure and hormones.

Genetics determine who is susceptible to these triggers.

Melasma is a chronic, recurrent condition, not a temporary blemish.

Effective management requires a long-term commitment to sun protection and professional guidance.

Definition

What Melasma Is (and Isn't)

Melasma is a common, acquired skin condition that manifests as brown, tan, or blue-gray patches on the skin, most commonly on the face. It is a form of hyperpigmentation. It is not a sign of poor health, a cancerous condition, or a result of a lack of cleanliness. It is a benign condition that primarily affects a person's appearance.

Explanation

The Hormonal-Sun-Genetic Triangle

Melasma happens at the intersection of three main factors. Sun exposure provides the initial trigger. Hormones amplify the trigger. Genetics determine the threshold at which the trigger causes an effect. Think of it as a lock (genetics), a key (hormones), and a keyhole (sun exposure). Without all three, the door doesn't open. This explains why melasma can appear suddenly during pregnancy or with birth control use, even with what might seem like average sun exposure.

Questions

Frequently asked questions

Why does melasma happen on the face?

The face has a high concentration of melanocytes and hormone receptors and is most frequently exposed to UV light.

Why does melasma happen to some people and not others?

It comes down to genetics and hormones. People with a family history of melasma or those with fluctuating hormones are much more likely to develop it.

Why does melasma happen suddenly?

It can appear suddenly during a major hormonal shift, such as pregnancy or starting a new birth control pill, which effectively lowers the threshold for UV triggers.

Why does melasma happen after sun exposure?

Sun exposure is the primary trigger. UV radiation directly stimulates the melanocytes to produce more melanin.

References

Sources

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

  1. The vast majority of melasma cases occur in women, with a significant onset during pregnancy or with hormonal contraception.
  2. Melasma almost always involves sun-exposed areas, with symptoms worsening after sun exposure.
  3. A first-degree relative with melasma is a well-established risk factor.
  4. Biopsies of melasma lesions show increased melanin in the epidermis and/or dermis, confirming the overproduction.