The three main types
Post-inflammatory hyperpigmentation (PIH)
PIH is the dark mark left behind after skin inflammation -- a pimple, a scratch, an insect bite, or any wound that triggers the skin's healing response. The inflammation stimulates melanocytes to produce excess melanin, which deposits as a dark patch. PIH is extremely common in medium-to-deeper skin tones, including across East, Southeast, and South Asian skin, where melanocytes are more active.
PIH is not the same as scarring. It is a pigmentation issue, and it fades on its own -- but in Asian skin, this natural fading can take 6 months to 2 years without any intervention. That is a realistic timeline, not a product failure.
Melasma
Melasma is a specific type of hyperpigmentation characterised by larger, irregular patches -- often across the cheeks, upper lip, forehead, and bridge of the nose. It is strongly linked to hormonal changes (pregnancy, oral contraceptives), UV exposure, and heat. It is more common in women and more prevalent in Asian and Latin American populations than in fair-skinned groups.
Melasma is notoriously difficult to treat and prone to recurrence. Even after successful fading, it returns with UV exposure or hormonal shifts. It requires professional assessment, and over-the-counter approaches may provide some improvement but are rarely sufficient on their own.
Sun spots (solar lentigines)
Sun spots are discrete, flat, well-defined dark spots caused by cumulative UV exposure. They are distinct from freckles (which are genetic and appear at a young age). Sun spots become more common from the mid-30s onward. They do not fade on their own without intervention, but they are generally easier to address than melasma.
No brightening ingredient works adequately if UV exposure continues daily. UV is the primary driver of melanin production and directly undermines any fading treatment. Daily broad-spectrum SPF 30 or higher -- applied generously and reapplied every 2 hours in direct sun -- is the essential foundation before any other intervention. In humid Asian climates with intense UV year-round, this is non-negotiable.
Ingredients commonly used for brightening
The following ingredients are commonly included in products marketed for brightening and hyperpigmentation. Evidence quality varies, and this is noted for each. None of these are described here as treatments for any condition.
Niacinamide
Inhibits the transfer of melanin from melanocytes to skin cells. Well-studied, well-tolerated, broadly safe for all skin tones. Works slowly but steadily.
Good clinical evidenceVitamin C (ascorbic acid)
Antioxidant that inhibits melanin synthesis. Effective but unstable -- formulation quality matters significantly. Can sting on sensitive skin.
Good clinical evidenceAzelaic acid
Inhibits tyrosinase (the enzyme that triggers melanin production). Also anti-inflammatory, making it particularly suited for PIH following acne.
Good clinical evidenceTranexamic acid
Newer brightening ingredient with growing evidence for melasma specifically. Generally well-tolerated, including on sensitive skin.
Moderate clinical evidenceAlpha arbutin
A gentler derivative of hydroquinone; inhibits melanin production. More widely available than hydroquinone in Asian markets.
Moderate evidence; gentler than HQKojic acid
Derived from fungi; tyrosinase inhibitor. Commonly used in Asian skincare, particularly in Japan and Korea. Can cause irritation at high concentrations.
Traditional use + some clinical dataMost brightening ingredients require consistent daily use for 8-12 weeks before visible change. Deep PIH or melasma may require 6 months or longer. Products that promise dramatic results in days are not being truthful about the biology of melanin turnover. Patience, SPF, and consistency matter more than switching products frequently.
What to be cautious about
- Hydroquinone: A prescription-strength tyrosinase inhibitor with good evidence for melasma, but associated with ochronosis (a blue-black discolouration) with prolonged unsupervised use. It is not recommended for long-term continuous use without professional guidance.
- Exfoliants + sun exposure: Regular AHA exfoliation increases UV sensitivity. If you are using AHAs (glycolic, lactic, mandelic acid), daily SPF is even more critical.
- Over-exfoliating for dark spots: Aggressive exfoliation can cause new inflammation, which causes new PIH -- worsening the overall picture. A steady, gentle approach outperforms aggressive protocols for PIH-prone skin.
If you have widespread or persistent pigmentation patches -- particularly symmetrically placed across the cheeks or upper lip -- please see a dermatologist. Melasma has specific treatment protocols and is prone to worsening with approaches that are unsuitable for its type and depth. Self-treating melasma without a confirmed diagnosis often leads to disappointing or counterproductive outcomes.