Melasma is one of the most commonly misdiagnosed things people try to treat at home. It gets mistaken for sun spots, for age spots, for post-acne marks — and because those respond to quite different approaches, a lot of money gets spent on products that were never going to work.
It is worth knowing what you are actually looking at before you buy anything.
What melasma actually is
Melasma is an acquired pigmentation disorder that shows up as symmetrical brown or grey-brown patches, almost always on the face. The classic pattern is across the cheeks, the bridge of the nose, the forehead, and the upper lip. The symmetry is the giveaway — sun spots appear where the sun happened to hit, in no particular arrangement. Melasma turns up in near-mirror-image patches on both sides of the face.
Underneath, the melanocytes — the cells that produce pigment — are not more numerous. They are more active. They are producing and distributing more melanin than they should, and they have become unusually responsive to being triggered.
That distinction matters enormously, and it is the single thing most product marketing glosses over. You are not dealing with a stain that can be removed. You are dealing with cells that are behaving differently, and that will keep behaving differently unless something changes their inputs.
The three things driving it
1. Light — and not only sunlight
Ultraviolet exposure is the best-established trigger. But the research over the past decade has made something else clear: visible light drives melasma too, particularly the blue-violet end of the spectrum. That includes light coming through windows, and on overcast days.
This is why people who are diligent with sunscreen still see melasma worsen. Most conventional sunscreens are formulated against UVA and UVB. They do very little against visible light. The effect is most pronounced in medium and deeper skin tones, which is also where melasma is most common.
2. Hormones
Melasma is far more common in women, and it clusters around hormonal events — pregnancy (where it is common enough to have its own name, chloasma or the "mask of pregnancy"), combined oral contraceptives, and hormone replacement therapy. Oestrogen and progesterone both appear to increase melanocyte sensitivity.
This is also why melasma sometimes fades on its own after pregnancy, and why it can return years later without any obvious change in sun habits.
3. Genetics
A substantial proportion of people with melasma have a close relative with it. Predisposition is strongly linked to skin phototype — it is most common in people with Fitzpatrick III to V skin, meaning olive through to deep brown tones, and it is particularly prevalent in people of South Asian, East Asian, Hispanic, and Middle Eastern descent.
You cannot change this input. You can change how much you provoke it.
Why it keeps coming back
Here is the part that catches people out.
Most topical treatments work by interrupting pigment production — usually by inhibiting tyrosinase, the enzyme that starts the melanin manufacturing process. That works. Pigment production slows, existing pigment gradually sheds with normal skin turnover, and the patches lighten.
But nothing about that process makes the melanocytes stop being hyperactive. Remove the treatment, and they resume doing what they were doing. Add a trigger — a holiday, a summer, a pregnancy, a change in contraception — and they resume faster.
There is also a deeper problem. In many cases, some of the pigment has settled below the epidermis, in the dermis. Topical products barely reach it. Dermal melasma is markedly more stubborn than epidermal melasma, and it is a large part of why two people using the same product get completely different results.
Clinically, melasma is managed rather than cured. That is not a marketing failure — it is the actual nature of the condition, and any product implying otherwise is overselling.
What this means practically
A few things follow from all of the above:
- Light protection isn't optional, it's the foundation. Any active you use is working against your daily light exposure. If that exposure is unmanaged, you are pushing against a door that keeps swinging back.
- Tinted sunscreen outperforms untinted for melasma specifically. The iron oxides that provide the tint also block visible light. This is one of the few areas where a cosmetic feature has a genuine functional benefit.
- Judge progress in months, not weeks. Skin turnover means visible change takes at minimum two full cycles. Anything promising results in days is describing something other than pigment reduction.
- Expect maintenance. The realistic goal is control, not permanent removal. Plan for an ongoing routine rather than a course of treatment with an end date.
- Aggressive isn't better. Melasma responds badly to inflammation. Harsh exfoliation, over-strong actives, and irritating routines can all darken it — the inflammation itself triggers more pigment.
When to see someone
If patches are changing shape, appearing on one side only, raised, or bleeding, that is not melasma and it needs to be looked at by a doctor. Melasma is flat, symmetrical, and stable in outline.
For genuine melasma, a dermatologist can distinguish epidermal from dermal involvement — which is the single most useful piece of information for setting expectations, and it isn't something you can determine yourself.
The short version: melasma is overactive pigment cells reacting to light, hormones, and genetics — not a stain to be scrubbed off. Treatments slow production; they don't switch the cells off. Sun and visible-light protection does more than any single active ingredient.
Further reading
The research base here is substantial and freely searchable: