Anua Niacinamide 10 + TXA 4 Serum: for the marks old breakouts leave

What do niacinamide and tranexamic acid do for dark marks?

Melanin is the substance that gives skin its color. When a pimple heals, the inflamed spot can leave behind a patch with extra melanin in it. That flat brown or dark mark has a medical name, post-inflammatory hyperpigmentation, or PIH for short. The American Academy of Dermatology (AAD) page on fading dark spots in darker skin tones says a spot a few shades darker than your skin usually fades within 6 to 12 months, once its cause has stopped. This serum is made to help it fade sooner.

For niacinamide, a 2002 paper in the British Journal of Dermatology reports two trials. In the first, 18 Japanese women with dark patches compared a 5% niacinamide moisturizer with the same moisturizer made without it. In the second, 120 people with tanned faces each used two of three products: a plain base, a sunscreen, or a sunscreen with 2% niacinamide. The niacinamide group in that second trial also wore sunscreen, so it can’t show which of the two did the work. Only the first trial tested niacinamide on its own. After four weeks, the side with niacinamide showed less pigmentation. Anua uses 10% here, which is twice the 5% strength used in that trial. The paper can’t tell us whether 10% works any better than 5%.

Tranexamic acid, often shortened to TXA, has more recent trials behind it. A 2026 review in the Journal of Cosmetic Dermatology gathers the trials of TXA on the skin for PIH. They used 2% to 5% twice a day, in groups of 35 to 60 patients. Lightening showed from about four to eight weeks. The same review warns that marks can come back after people stop. The 4% in this bottle sits inside the range those trials used.

Those trials tested treatments for a medical skin condition. This serum is sold as a cosmetic, so it can only claim to help the look of uneven tone. If you’re not sure what a dark patch is, a dermatologist can tell you.

What’s in it?

Anua builds the serum around three pigment ingredients and states the strength of each one: 10% niacinamide, 4% tranexamic acid and 2% arbutin. It calls them a trio for dullness and dark spots. The list carries two forms of arbutin, plain arbutin and alpha-arbutin. Anua’s 2% figure names arbutin and doesn’t say how the two are split.

Anua names ceramides and hyaluronic acid as the ingredients that keep skin feeling moisturized. Hyaluronic acid turns up in many forms down the list. The single ceramide, ceramide NP, sits near the end. There are also plant oils and extracts further down, including centella. Anua lists the serum as fragrance-free and made without artificial color.

How does it feel, and how do you use it?

Anua describes a thin, watery serum that sinks in fast and isn’t greasy. That kind of texture is easy to wear under moisturizer and sunscreen, so we’d suggest it mainly to people with oily or combination skin.

Anua’s directions are to pat a few drops onto the areas with dark marks, morning and night, before moisturizer. They also ask for SPF 30 or higher in the day. Don’t skip that part. The AAD says treatment for dark spots begins with sunscreen, and it names the sun’s visible light as one cause of them. It points to a broad-spectrum SPF 30 or higher, and a tinted formula with iron oxide to block that visible light.

On tolerance, a 2024 review in Antioxidants says clinical tests found no stinging from niacinamide at up to 10%, and no irritation at up to 5%. It doesn’t report on irritation at 10%, the strength in this bottle. Anua’s ingredient list also carries betaine salicylate, a salicylic acid compound, and 3-O-ethyl ascorbic acid, a vitamin C derivative. Anua gives no strength for either. If acids or vitamin C tend to bother your skin, start with once a day and patch-test first.

Who’s it for — and who should skip it?

It’s best for oily, combination and breakout-prone skin with marks left by old pimples.

If breakouts leave you with dark marks and you’ll wear sunscreen every morning, this serum is a good fit.

Skip it if you want an all-round glow more than help with specific marks. The Beauty of Joseon Glow Deep Serum is built on rice and alpha-arbutin for that everyday brightening job. For how niacinamide works across a routine, our guide to niacinamide in Korean skincare goes further. For the other ways to fade dark spots, including sunscreen and alpha-arbutin, see our guide to Korean skincare for dark spots.

Is it worth it?

Yes, if you’re patient. Both lead ingredients have trial evidence for uneven pigment, and Anua states the strength of each. The texture is easy to fit into a routine. The main drawback is how long it takes. Changes in the studies showed from four to eight weeks, so we’d give it the full eight, with sunscreen every day, before deciding. If you’re new to brightening serums, use it once a day for the first couple of weeks. If you’ve used niacinamide before without trouble, morning and night is fine.