Short answer: look for niacinamide and tranexamic acid (TXA) in a Korean dark spot serum (sérum anti-taches coréen). Both have been tested on human skin: a 5% niacinamide cream reduced the look of hyperpigmentation after four weeks, and a 3% TXA solution lowered melasma scores over twelve weeks. Korean serums combine them in different ways, and these three show three label types. Both, with the most niacinamide: the Anua Niacinamide 10 TXA 4 Dark Spot Correcting Serum 30ml (€20.00; 10% niacinamide, 4% TXA, 2% arbutin). Both, with half the niacinamide: the numbuzin No.5+ Glutathione Vitamin Concentrated Serum (30 ml, €21.00; the same 4% TXA, 5% niacinamide). Niacinamide, no TXA: the AXIS-Y Dark Spot Correcting Glow Serum 50ml (€14.00; 5% niacinamide, about €0.28 per ml). Choose Anua or numbuzin for TXA, numbuzin or AXIS-Y if 10% niacinamide is too much for your skin, and AXIS-Y for the lowest price per ml. Prices are Piyonna's regular prices on 19 October 2026; Piyonna runs frequent promotions, so check the product page for today's price.
Do niacinamide and tranexamic acid help with brown spots (taches brunes)?
Yes, both have been tested on human skin: niacinamide reduced the look of hyperpigmentation after four weeks, and tranexamic acid lowered melasma scores over twelve weeks with no significant difference from a hydroquinone formula and fewer side effects. In the niacinamide study, a 5% niacinamide moisturiser reduced the appearance of hyperpigmentation compared with the base cream in 18 people. Lab work in the same paper shows how it works: niacinamide slows the transfer of pigment between skin cells rather than blocking pigment production (Hakozaki et al., 2002; the lead author worked at Procter & Gamble).
In the tranexamic acid study, 50 women with melasma applied a 3% tranexamic acid solution to one side of the face and 3% hydroquinone with 0.01% dexamethasone to the other, twice a day for 12 weeks. Melasma scores fell on both sides with no significant difference between them, and the tranexamic acid side had fewer side effects (Ebrahimi and Naeini, 2014). These studies used their own formulas, so they show what the ingredients can do, not what a particular bottle will.
Anua and numbuzin also contain arbutin, which acts one step before niacinamide: it slows tyrosinase, the enzyme that starts pigment production, as shown in cultured human pigment cells (Maeda and Fukuda, 1996; Shiseido Research Center).
Which Korean dark spot serum should you choose (sérum anti-taches coréen)?
Choose Anua for the highest niacinamide (10%) plus 4% tranexamic acid and 2% arbutin, numbuzin for tranexamic acid with half the niacinamide, and AXIS-Y for a simple niacinamide serum at the lowest price per ml.
AXIS-Y aims its serum at post-breakout marks and sun-exposed skin, but none of the three brands reports results for one kind of mark, and the research doesn't separate them either: the tranexamic acid study above was in melasma, the niacinamide study in hyperpigmentation. Brown patches on both cheeks can be melasma; show those to a dermatologist before you choose a serum.
Anua Niacinamide 10 TXA 4 Dark Spot Correcting Serum
Tranexamic acid 4% · niacinamide 10% · arbutin 2% · 30 ml · €20.00 regular price (about €0.67 per ml)
Choose it if you want the highest niacinamide of the three, with tranexamic acid and arbutin in the same bottle. If 10% niacinamide has made your skin flush before, numbuzin and AXIS-Y have half as much. If you prefer a serum without arbutin, AXIS-Y has none.
The brand's directions: a few drops on the areas of concern, morning and night before moisturiser, with SPF 30+ during the day. See the Anua serum at Piyonna.
numbuzin No.5+ Glutathione Vitamin Concentrated Serum
Tranexamic acid 4% · niacinamide 5% · panthenol 5% · 30 ml · €21.00 regular price (about €0.70 per ml)
Choose it if you want tranexamic acid with half the niacinamide of Anua, plus 5% panthenol. Niacinamide and tranexamic acid are its main actives; the glutathione and vitamin C named on the bottle are listed at 0.01% and 0.2% (a vitamin C derivative).
The brand's directions: pat a suitable amount into the skin. See the numbuzin serum at Piyonna.
AXIS-Y Dark Spot Correcting Glow Serum
Niacinamide 5% · no tranexamic acid · 50 ml · €14.00 regular price (about €0.28 per ml)
Choose it if you want a simple niacinamide serum and the most product for your money: 50 ml for €14.00. If you also want tranexamic acid, Anua and numbuzin each have 4%.
The brand's directions: pat a small amount over the face or onto targeted areas, as a daily serum. See the AXIS-Y serum at Piyonna.
What is actually in the AXIS-Y, Anua and numbuzin serums?
Only Anua and numbuzin contain tranexamic acid, 4% each, and only Anua says so in its name; AXIS-Y has none. We compared each brand's published ingredient list with Piyonna's product pages. Prices are Piyonna's regular prices on 19 October 2026 and include customs duties and VAT. Piyonna runs frequent promotions, so the price on the product page is often lower than the regular price; check it before you buy. Orders over €20 ship free, with estimated delivery in 7–15 business days.
| Serum (size) | Tranexamic acid | Niacinamide | Regular price at Piyonna (per ml) | Arbutin | Vitamin C (INCI) | Glutathione |
|---|---|---|---|---|---|---|
| Anua Niacinamide 10 TXA 4 (30 ml) | 4% | 10% | €20.00 (about €0.67) | 2% arbutin, plus alpha-arbutin | 3-O-ethyl ascorbic acid, amount not stated | None |
| numbuzin No.5+ Glutathione Vitamin Concentrated Serum (30 ml) | 4% | 5% | €21.00 (about €0.70) | Alpha-arbutin, amount not stated | 3-O-ethyl ascorbic acid 0.2% | 0.01% |
| AXIS-Y Dark Spot Correcting Glow Serum (50 ml) | None | 5% | €14.00 (about €0.28) | None | None (acerola fruit extract only) | Present, amount not stated |
The table compares labels, not results: each brand runs its own tests in its own way, so we leave those figures out. numbuzin publishes its amounts in ppm on its Korean site (100 ppm of glutathione is 0.01%), and Piyonna's product page gives the same 5% niacinamide and 4% tranexamic acid.
Can you use niacinamide and tranexamic acid together, or with vitamin C or retinol?
Yes. Anua and numbuzin already combine niacinamide and tranexamic acid with a vitamin C derivative (3-O-ethyl ascorbic acid) in one bottle, and none of the three brands' product pages warns against pairing its serum with vitamin C or retinol.
Already using retinol or a strong acid at night? Put the dark-spot serum in the morning under sunscreen and keep the retinol for the evening, so you are not starting several new actives at once. Use one of these serums at a time: layering Anua and AXIS-Y, for example, doubles up on niacinamide and makes it hard to tell which one is working.
Which one is gentler on sensitive skin, and how long before you see a difference?
If niacinamide has made your skin flush or sting before, start with AXIS-Y or numbuzin, which contain half the niacinamide of Anua, and give any of them four to twelve weeks with daily sunscreen before you judge it. A safety assessment found no stinging from niacinamide up to 10% and no cumulative irritation up to 5% (Cosmetic Ingredient Review Expert Panel, 2005). Its use tests stopped at 5%, which is why we point niacinamide-sensitive skin to the 5% serums.
Four to twelve weeks is how long the studies above ran. Change one product at a time so you can see what is working.
Are there side effects, and when should you see a dermatologist (effets secondaires)?
Stop using the serum and get professional advice if redness or discomfort appears; Piyonna's product pages for all three serums say the same.
- Patch-test first: apply a little to a small area for a few days before using any of these serums on your whole face.
- Arbutin: reactions are rare, but a 2021 review advises caution with arbutin products (Boo, 2021). Anua and numbuzin contain it; AXIS-Y doesn't.
- Eye area: keep the Anua serum away from the eyes, as the brand directs.
- Sun: wear sunscreen every day with any of these serums; Anua specifies SPF 30+.
- Patches on both sides of the face: the American Academy of Dermatology describes melasma as patches on both sides of the face, often on the cheeks, forehead, nose, chin or above the upper lip (AAD). If that sounds like your marks, see a dermatologist before relying on a cosmetic serum.
To match an ingredient to your kind of mark, see our guide to ingredients for dark spots and uneven skin tone, and for post-acne marks, our article on azelaic acid and PDRN. You can browse the full Anua, numbuzin and AXIS-Y ranges at Piyonna.
Sources
- Hakozaki T, Minwalla L, Zhuang J, et al. The effect of niacinamide on reducing cutaneous pigmentation and suppression of melanosome transfer. British Journal of Dermatology. 2002. PMID 12100180
- Ebrahimi B, Naeini FF. Topical tranexamic acid as a promising treatment for melasma. Journal of Research in Medical Sciences. 2014. PMID 25422661
- Maeda K, Fukuda M. Arbutin: mechanism of its depigmenting action in human melanocyte culture. Journal of Pharmacology and Experimental Therapeutics. 1996. PMID 8632348
- Cosmetic Ingredient Review Expert Panel. Final report of the safety assessment of niacinamide and niacin. International Journal of Toxicology. 2005. PMID 16596767
- Boo YC. Arbutin as a skin depigmenting agent with antimelanogenic and antioxidant properties. Antioxidants. 2021. PMID 34356362
- American Academy of Dermatology. Melasma: signs and symptoms
- Ingredient lists, stated amounts and directions: Anua (and Anua Korea), numbuzin Korea, AXIS-Y, and the ingredient list shown on Piyonna's AXIS-Y product page
This article is general cosmetic information and not medical advice.
