Tranexamic acid serum for dark spots: two Korean picks

The breakout is gone, but the brown mark it left is still there. The spots that were faint in spring look darker after summer. If that is the problem you are trying to solve, a tranexamic acid serum for dark spots is one of the options you will be offered, and two Korean versions put the ingredient right in their names: Anua’s Niacinamide 10% + TXA 4% Dark Spot Correcting Serum and haruharu wonder’s Centella 4% TXA Dark Spot Go Away Serum. Both lead with the same number. The formulas behind it are built quite differently.

What does tranexamic acid do for dark spots?

Tranexamic acid, often shortened to TXA, helps brown marks and patchy tone look lighter over several weeks. Most of what we know about it on skin comes from small studies in people with melasma, a condition of stubborn brown patches on the face.

In a 2016 study from Ajou University in Korea, 23 people applied a 2% tranexamic acid formula to the whole face for 12 weeks. Patch severity scores improved in 22 of them, and skin samples showed less pigment in the outer layer. The researchers also looked for why. Their conclusion was that “suppression of ET-1 could be one of the mechanisms of action of TA on melasma”, ET-1 being one of the messenger molecules passed between neighboring skin cells that the team measured.

Niacinamide, which both serums also contain, works on a different step, covered below.

Does tranexamic acid serum actually work?

Partly, and the honest version matters before you buy. In a 2012 double-blind trial in Thailand, 23 women applied a 5% tranexamic acid gel to one side of the face and the same gel without it to the other, twice a day for 12 weeks, with sunscreen every morning. Pigment readings fell in 18 of the 23 women (78.2%), but the tranexamic acid side did not do better than the plain side, and it caused more redness.

A 2024 meta-analysis of 22 randomized trials with 1,280 patients found tranexamic acid lowered patch severity overall. Tablets did the most, then injections, and applying it to skin did the least. Tablets and injections are medical uses; a serum is the weakest of the three routes.

So a TXA serum is worth trying for brown marks if you can give it 3 months and wear sunscreen daily, with modest expectations. Two of the three studies above were done in Asian participants with melasma, so results on post-breakout marks or on fair skin are less well tested.

What is the difference between the Anua and haruharu wonder TXA serums?

The Anua serum is a multi-active brightening formula. The haruharu wonder serum is a short, centella-based one. Both are water-based, and both list niacinamide just ahead of tranexamic acid.

Anua Niacinamide 10% + TXA 4% Dark Spot Correcting Serum. Anua states 10% niacinamide, 4% tranexamic acid and 2% arbutin. Further down the list come alpha-arbutin, betaine salicylate, 3-O-ethyl ascorbic acid (a vitamin C derivative), ceramide NP, panthenol, several forms of hyaluronic acid, and a run of plant oils including macadamia, olive, jojoba and grape seed. The brand describes it as fragrance free and directs use morning and night before moisturizer, with SPF 30 or higher during the day.

haruharu wonder Centella 4% TXA Dark Spot Go Away Serum. The full list has 18 ingredients: water, propanediol, niacinamide, tranexamic acid, then madecassoside and other centella asiatica compounds, ascorbic acid and sodium ascorbyl phosphate (two forms of vitamin C), tocopherol (vitamin E) and pear fruit extract. There are no oils and no arbutin. The brand’s directions are simply to apply evenly and pat in.

Order on the label tells you something here. In the US, ingredients above 1% must be listed in descending order of concentration, so in both serums there is at least as much niacinamide as tranexamic acid. Our guide to reading an ingredient list explains where that rule stops being useful.

Which TXA serum suits your skin?

It depends on whether you want more actives in one bottle or fewer.

The Anua serum suits you if you want one product to cover several brightening routes at once and your skin tolerates actives well. The trade-off is that it already contains niacinamide, two arbutins, a vitamin C derivative and a salicylate, so stacking it with other brightening serums piles even more on.

The haruharu wonder serum suits you if your skin reacts easily, if you are already using a retinoid or an acid, or if you want a single brightening step without oils. It is the simpler of the two.

Can you use tranexamic acid and niacinamide together?

Yes, and both serums already do. Niacinamide works on a later step than TXA. A 2002 Procter & Gamble study found it blocked 35% to 68% of pigment transfer between skin cells in lab models, and in 18 people a 5% niacinamide moisturizer lightened brown spots after 4 weeks compared with a plain one. The authors concluded that “niacinamide is an effective skin lightening compound that works by inhibiting melanosome transfer from melanocytes to keratinocytes”. That study was run in Japanese women.

Alpha-arbutin, one of the two arbutins in the Anua serum, has a safety ceiling worth knowing. The EU’s Scientific Committee on Consumer Safety considers it safe “in a concentration up to 2% in face creams”, and noted that combining it with certain related ingredients had not been evaluated. That is one more reason not to layer several brightening serums at once. More on each ingredient: tranexamic acid, niacinamide and alpha arbutin.

How do you use a tranexamic acid serum?

Apply a few drops after cleansing and toner, before moisturizer. Once a day is a reasonable start; Anua’s directions allow morning and night.

• Sunscreen every morning. The 5% trial had everyone wear sunscreen each morning, and Anua’s directions call for SPF 30 or higher during the day.
• One brightening product at a time. Pick one of these serums rather than adding a third brightener on top.
• Give it 12 weeks. Photograph the marks in the same light before you start and compare after 3 months.
• Stop if your skin stays red or stings. The 5% trial found more redness on the tranexamic acid side.

If you are working through breakout marks, our routine for hormonal breakouts shows where a step like this fits, and niacinamide with vitamin C covers the pairing inside the haruharu wonder formula.

Editor’s note

The haruharu wonder TXA serum is part of my evening routine. After a cream toner sprayed through a mist pump, it goes on with a bakuchiol eye cream, before the lotion from my dermatologist. I have also used the Anua serum. For the marks breakouts leave, what matters most to me is daily care and applying sunscreen properly.

I learned the layering rule the hard way. Once, I stacked several melanin-care products on top of each other, and my skin answered with dry patches and roughness. The spots under my eyes also come out in summer and fade in winter, so the season is always part of the picture when they change.

This article is for general cosmetic information and is not medical advice. For brown patches that spread or change, see a dermatologist. Product ingredient lists can change; check the current list on the package.