Niacinamide, alpha-arbutin, tranexamic acid: which one for your dark spots?

You have a dark spot. You look for a serum. You land on fifteen active names and zero explanation of which to choose. It is one of the worst-explained subjects in skincare, so let us start from the beginning.

First: which kind of spot are we talking about?

Three very different things hide behind the word « spot », and they are not treated the same way.

The post-inflammatory mark. It appears where there was a spot, an irritation, a scratch. If it is red or pink, it is not pigment yet: it is inflammation, and it goes away on its own in three to six months. If it is brown, the skin has made melanin there, and a brightening active clearly speeds things up.

The solar lentigo. The well-defined brown spot, often on the cheekbones, forehead, backs of the hands. It is twenty years of sun accumulated. It is the most stubborn.

Melasma. Broader patches, often symmetrical, on the cheeks, upper lip or forehead. Hormonal in origin — pregnancy, the pill — and made worse by sun and heat. It is the most capricious: it comes back easily.

Knowing which one you have changes the active to choose.

How skin makes a spot

A simple image: in the skin, cells called melanocytes make the pigment, then distribute it to neighbouring cells, which gradually travel up to the surface.

So there are three moments where you can intervene: prevent production, block distribution, or speed up removal of what is already there.

Each active works at one of these three moments. That is why combining two works better than doubling the dose of one.

Alpha-arbutin — the default choice

What it does: it slows tyrosinase, the enzyme that triggers melanin production. It blocks at the source.

Who for: just about everyone. It is the most versatile active of the lot, effective on brown post-acne marks as well as sun spots.

Useful concentration: 1 to 2 %. Beyond that, you gain nothing.

Tolerance: excellent. No irritation, no photosensitivity, compatible with the rest of your routine.

If you are starting out and do not know what to take, this is the one. Beauty of Joseon's Glow Deep Serum pairs it with rice and remains our most requested brightening serum.

Tranexamic acid — for melasma

What it does: it acts on communication between cells, upstream of pigment production. Originally it is an anti-haemorrhagic medicine — its effect on melasma was discovered by chance, in patients treated for something else.

Who for: it is the best available active against hormonal melasma, the kind that resists everything else. It also works very well on persistent redness.

Useful concentration: 2 to 5 %.

Tolerance: very good, often better tolerated than vitamin C on reactive skin.

It is often paired with niacinamide, and that duo is one of the most effective on the Korean market.

Niacinamide — the supporting active

What it does: it blocks the transfer of pigment to surface cells. In other words, melanin is made but does not travel up. It also strengthens the skin barrier and regulates sebum, which makes it the most versatile active in skincare.

Who for: everyone, as a companion. On its own it is decent; paired with alpha-arbutin or tranexamic acid it becomes very good.

Useful concentration: 5 to 10 %. Beyond that, tingling increases with no added benefit.

This is the active you keep permanently in your routine, whatever your goal.

Vitamin C — powerful but demanding

What it does: it slows tyrosinase, like arbutin, but adds an antioxidant action that protects against sun damage. It brightens the overall complexion, not just the spots.

The problem: pure L-ascorbic acid is unstable. It oxidises in light and air, turns brown-orange, and becomes ineffective. A vitamin C serum that has turned brown should be thrown away. It can also sting on sensitive skin.

How to use it: in the morning, before sunscreen. Korean formulations often prefer stable derivatives, less powerful but more reliable over time.

What is useless

Lemon. It comes back regularly on social media. Its pH is 2, it burns the skin, and the furocoumarin it contains causes sun burns — which leave, ironically, dark spots. Do not put lemon on your face.

Hydroquinone bought online. It works, but it is regulated in Europe for good reasons: used without medical supervision it can cause ochronosis, a permanent blue-grey discolouration. If you need it, it is by prescription.

Changing serum every three weeks. No brightening active shows results before eight weeks. If you change before that, you will never know what was working.

Sunscreen is not just one more piece of advice

It is half the treatment, and the half people skip.

The reasoning is simple: your actives slow melanin production. The sun restarts it. Without daily protection, you are emptying a bath with the tap running.

For melasma it is even more true: it is triggered by visible light as much as by UV. Tinted sunscreens, whose pigments block part of that light, are markedly more effective than clear ones in this particular case.

The protocol, summarised

Brown post-acne marks: alpha-arbutin or niacinamide, in the evening. Allow eight to twelve weeks.

Established sun spots: alpha-arbutin + niacinamide, plus a gentle exfoliant twice a week to speed up cell turnover. Allow three to six months.

Melasma: tranexamic acid + niacinamide, tinted sunscreen without exception. And accept that it is maintenance, not a cure.

Dull complexion with no particular spot: vitamin C in the morning, and above all good hydration — a dull complexion is very often a dehydrated one.

In every case: one new active at a time, and patience. Our dark spots selection gathers the matching formulas, and the skin diagnostic points you in the right direction in two minutes if you are unsure.

This article is informational and does not replace medical advice. A spot that changes shape, colour or size should be shown to a dermatologist.