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

Dark spots are the concern people bring to us most. On our skin test, 60% of the 315 people who had taken it by mid-October put them first, and most were marks left behind by acne. So the question we're asked most often is a fair one: which serum?

Here are the three ingredients we think are worth knowing, what each one actually does, and how to choose.

How a dark spot forms

Skin makes its colour in cells called melanocytes, using an enzyme called tyrosinase. When skin is inflamed by a spot, a burn or a scratch, or simply hit by the sun, those cells make extra pigment and pass it up into the surface cells. A dark spot is that extra pigment, stuck in one place.

Each of the three ingredients interrupts that process at a different step. That's why they can work well together, and why none of them works without sunscreen: the sun restarts the whole process every day.

Niacinamide

Niacinamide is a form of vitamin B3. It doesn't stop pigment being made; it slows the hand-over of pigment into the surface cells, so less of it shows. It also strengthens the skin barrier, calms redness and helps with oil, which is why it turns up in so many routines.

It suits almost everyone. Studies have used anything from 2% to 5% with good results, and 10% is common in serums now. Higher isn't automatically better: some skin gets red or itchy at 10%, and does fine at a lower strength. The Ordinary Niacinamide 10% + Zinc 1% is the oil-control version; Beauty of Joseon Glow Serum: Propolis + Niacinamide is softer.

Tranexamic acid

Tranexamic acid, or TXA, works further upstream. It calms some of the signals that tell melanocytes to make pigment in the first place, especially the ones linked to inflammation and heat. That's why it's used for stubborn, patchy pigmentation and melasma-type marks, as well as acne marks.

On the skin it's gentle and rarely irritates. It's often paired with niacinamide because the two work at different steps. Anua Niacinamide 10% + TXA 4% Serum is exactly that pairing in one bottle, and it's what we'd reach for when marks have been around for months.

Tranexamic acid tablets are a different matter. They're a prescription medicine with real risks, and only a doctor should decide whether you take them.

Alpha arbutin

Alpha arbutin slows tyrosinase, the enzyme that makes pigment, so it acts right at the start. It's one of the gentlest brightening ingredients there is, which makes it the one we'd suggest for sensitive skin, or for anyone who has been stung by vitamin C.

Beauty of Joseon Glow Deep Serum: Rice + Alpha Arbutin pairs it with rice extract, and it can be used morning and night without a rest day.

So which one?

• Mostly acne marks, oily skin, and some redness: niacinamide.
• Stubborn marks that haven't moved in months, or patchy, blotchy pigmentation: niacinamide with TXA.
• Sensitive skin that reacts to most things: alpha arbutin.
• Not sure: start with niacinamide. It does the most jobs and suits the most people.

Can you use them together?

Yes. None of the three clashes with the others, and they work at different steps, so layering two is fine. But add one at a time, a couple of weeks apart. If your skin reacts, you'll know which one to blame. Two well-chosen products used every day beat five used now and then.

They also sit happily alongside a gentle exfoliant like The Ordinary Glycolic Acid 7% Exfoliating Toner a few nights a week, which helps the darker surface cells shed. Don't start the acid in the same fortnight as a new serum.

The part that decides whether any of this works

Sunscreen, every morning, SPF 50 with PA+++ or higher. We know every guide says it. It's still the step that decides the result, because each unprotected day undoes a little of what the serum did. Our sunscreen guide helps you find one you'll wear.

Then give it time. Skin renews itself roughly once a month, so judge a serum at eight to twelve weeks, not at two.

What you're aiming for is an even tone and fewer marks, not lighter skin. If a spot is raised, growing, bleeding or changing colour, or if you have large patches that keep coming back, see a dermatologist. We sell the serums named here, so weigh our picks with that in mind. For the whole routine, start with fading dark spots.