Kojic Acid vs Alpha-Arbutin, Honestly: What Fades Dark Spots, How Long It Takes — and the EU Limits on Both

Kojic acid and alpha-arbutin are the two dark-spot ingredients you are most likely to meet on a European shelf. Both are marketed as the gentle alternative to hydroquinone, the prescription benchmark. Most comparisons of them online are written by brands that sell one or both — and so is this one: we make a product with each.

So this is the version with the sources attached: what each ingredient does, what was actually tested and on whom, which one is more likely to irritate, what the EU changed in 2025, and exactly what is in ours. If you only want the verdict, skip to how to choose.

First: which kind of dark spot?

“Dark spot” covers several different things, and they do not respond equally to any cream.

• Sun spots (solar lentigines, often called age spots): flat brown patches on the face and the backs of the hands after years of UV exposure.
• Marks left by spots, scratches or rashes (post-inflammatory hyperpigmentation): flat brown or grey-brown patches where inflammation has healed. They are more common, and last longer, in darker skin tones.
• Melasma: symmetrical patches on the cheeks, forehead or upper lip, made worse by sunlight, the contraceptive pill and pregnancy. It is a skin condition in its own right, it tends to return, and it is best managed with a dermatologist.

Most of the research below was done in melasma, because it is the hardest case to treat and the one dermatologists study most. Keep that in mind as you read: a result in melasma is not a promise for sun spots, and vice versa.

One rule comes before all of them. A mark that is new, changing in size, shape or colour, itchy, bleeding or crusting is not a skincare question. The NHS advises seeing a GP about any mole that changes and about any new or unusual mark on the skin that has not gone away after a few weeks. Never use a brightening product to fade something no one has looked at.

How kojic acid and alpha-arbutin work

Skin colour comes from melanin, which pigment cells called melanocytes make and pass on to the skin cells around them. The key enzyme in that process is tyrosinase, and both ingredients slow it down.

Kojic acid

Kojic acid is made by fungi, including the koji mould used to brew sake and soy sauce, which gave it its name. It blocks tyrosinase largely by binding the copper the enzyme needs to work. Japanese skincare brands have used it as a depigmenting ingredient since 1988, which is why much of the early safety data comes from Japan.

Alpha-arbutin

Arbutin is hydroquinone joined to a glucose molecule. The plant form, simply called arbutin, occurs in bearberry leaves. Alpha-arbutin is the same two building blocks joined the other way round, and much of the laboratory work on it was done by Ezaki Glico, the Japanese company that makes it. In the company’s 2004 study, alpha-arbutin reduced melanin in a three-dimensional human skin model to 40% of untreated levels without harming the cells.

Neither ingredient bleaches pigment that is already there. They reduce the supply of new melanin, and dark spots fade as pigmented cells reach the surface and are shed — a process measured in weeks. It also means niacinamide is a good companion rather than a duplicate: it acts on the transfer of pigment into skin cells, a different step. We went through that evidence in our niacinamide article.

What the studies actually show

Kojic acid: older, smaller, mostly combined

In a 1996 split-face study, 39 people with melasma used a glycolic acid formula with kojic acid on one side of the face and the same formula with hydroquinone on the other. Half responded equally to both; 28% did better on the kojic acid side and 21% on the hydroquinone side, a difference that was not statistically significant. The kojic acid formula was the more irritating of the two.

A 1999 study from Singapore added 2% kojic acid to a gel that already contained 10% glycolic acid and 2% hydroquinone, on one randomly chosen side of the face, in 40 women with melasma. After 12 weeks, more than half of the melasma had cleared in 60% of the women on the kojic acid side, against 47.5% on the side without it. Redness, stinging and peeling appeared on both sides and settled by the third week.

When kojic acid faced hydroquinone on its own, it lost. In a 2013 Indian study of 60 people with melasma, a cream with 0.75% kojic acid and 2.5% vitamin C worked more slowly than 4% hydroquinone, and less well over 12 weeks. Patients were allocated alternately rather than randomised, which makes the design weaker, but the direction matches the rest.

Alpha-arbutin: mostly laboratory, and one promising pilot

Alpha-arbutin’s reputation rests largely on laboratory work like the 2004 study above. An independent 2021 review of three decades of arbutin research, which declared no conflicts of interest, concluded that its lightening effect has been clinically evaluated alone and in combinations, that it rarely causes dermatitis, and that caution is warranted because hydroquinone may be generated during product use.

The most interesting recent trial tested the two ingredients together. In a 2025 randomised split-face pilot from Thailand, 30 people with melasma applied a cream with 5% alpha-arbutin and 2% kojic acid to one side of the face and the standard hydroquinone-based prescription “triple cream” to the other, for 12 weeks. On melanin measurements and severity scores, the two sides did not differ; the doctors’ overall assessment improved only on the prescription side. The arbutin–kojic side had less redness and stinging, and its melasma came back less severely after treatment stopped. The study was independent and declared no conflicts. It also used strengths that can no longer be sold as cosmetics in the EU — more on that below.

What pigment specialists recommend

In 2026, ten dermatologists and pigment specialists from Africa, Asia, Europe and the Americas published a global consensus on managing hyperpigmentation. Kojic acid does not appear in it. Arbutin is listed among several options for dark circles left by past inflammation, and as a second-line option for some other pigment disorders. For marks left by acne, the topical treatments the panel agreed on were thiamidol, azelaic acid, topical retinoids, hydroquinone and tranexamic acid.

One thing to know about that consensus: it was sponsored by Beiersdorf, the company behind thiamidol, which provided editorial assistance and, according to the paper, had no role in its conclusions — and seven of the ten authors declared ties to the company. That is a reason to weigh its enthusiasm for thiamidol carefully, not to dismiss the rest.

Which one irritates more?

Kojic acid, consistently. It was the more irritating formula in the 1996 trial. More importantly, it can sensitise: in a Japanese patch-test series published in 1995, 5 of the 8 people who had used skincare with 1% kojic acid had become allergic to it, developing facial dermatitis between one and twelve months after they started. An allergy is not the same as irritation. It does not settle with continued use, and it can flare every time you meet the ingredient again.

Alpha-arbutin’s record is quieter: the 2021 review found that arbutin rarely causes dermatitis. Its concern is a different one. Arbutin is built from hydroquinone, and hydroquinone can be released from it. Hydroquinone is banned from EU cosmetics — dermatologists prescribe it as a medicine — which is why the EU now requires hydroquinone in arbutin products to stay at the unavoidable trace level.

Is kojic acid banned in Europe?

No — but since 2025 it has been capped, and so has alpha-arbutin. Commission Regulation (EU) 2024/996, adopted on 3 April 2024, added both to the EU’s list of restricted cosmetic ingredients after the EU’s Scientific Committee on Consumer Safety concluded that each is safe only up to a limit.

For both forms of arbutin, the regulation adds that hydroquinone must stay as low as possible and no higher than the unavoidable trace level. Products with retinol must now carry the warning “Contains Vitamin A. Consider your daily intake before use” — if that is your next question, we covered retinol alternatives separately.

What this means when you shop:

• No kojic acid on the body. The 1% limit applies only to products for the face and hands, so kojic acid body lotions and soaps sold for use on the body do not meet EU rules. Nor does any product advertising 2% kojic acid, a strength still common on international marketplaces.
• Trial strengths don’t transfer. Several of the studies above used 2% kojic acid or 5% alpha-arbutin. No EU cosmetic can contain those amounts, so none can promise those results.
• Great Britain adopted the same kojic acid limit — 1%, in face and hand products only — in its own regulations in 2025.
• Percentages are rarely on the label. EU ingredient lists run in descending order down to 1%, so you can often see roughly where an active sits, but not its exact strength.

Kojic acid or alpha-arbutin: how to choose

You do not have to choose. The two are often combined, and the combination was well tolerated in the 2025 trial. If you use both, start one, wait two weeks, then add the other — so that if your skin reacts, you know which one to drop.

What is in ours

We make one product with each, so here is exactly what they contain — including the parts we would rather you read here than discover on your face.

Dark Spot Face Cream with Kojic Acid

Our Dark Spot Face Cream with Kojic Acid is a moisturiser, so it replaces your face cream rather than adding a step. Kojic acid is the twelfth of its 33 ingredients; EU law caps it at 1%, so that is the most it can contain. Around it are glycerin, betaine and sodium PCA, which hold water in the skin, and jojoba oil for softness.

Two honest notes. The vitamin C listed among its key ingredients is ascorbyl palmitate, and it sits near the end of the list, after the fragrance — so do not count it as a vitamin C treatment. And the cream is fragranced, with lemon and bitter-orange peel oils, patchouli and cedarwood among others. Given kojic acid’s allergy record, patch-test before using it on your face: a little on the inner arm, once a day for a few days.

Pigment Perfecting Serum

Our Pigment Perfecting Serum is built around alpha-arbutin, ninth of its 34 ingredients, with Bidens pilosa extract — the plant extract we looked at in our retinol alternatives article — and a little hyaluronic acid. Despite the name it is a light lotion rather than a watery serum, and it is fragranced too, including lemon peel oil and menthol, which some people feel as a tingle.

Neither product is a treatment for melasma or any other skin condition. They are cosmetics that help dark spots look lighter and skin tone look more even — and they will only do that alongside the next step.

Sunscreen matters more than either ingredient

Every trial above lasted 8 to 12 weeks, and every guideline puts sun protection first, because the light that created the spots keeps darkening them. The 2026 consensus calls photoprotection the mainstay of melasma prevention, treatment and maintenance, and it goes further than most advice: it recommends SPF 50 or higher with UVA protection, plus protection from visible light, which can deepen melasma and post-inflammatory marks. Only tinted sunscreens containing iron oxides or titanium dioxide have prevented that visible-light pigmentation in randomised trials.

Our Sun Protection SPF50 Stick, with tint is that kind of sunscreen: zinc oxide and titanium dioxide filters with iron oxide pigments. It contains fragrance too. If its tint does not suit your skin tone, the consensus suggests a broad-spectrum untinted sunscreen with an iron-oxide foundation on top.

How to use them, and how long to wait

1. Patch-test first, especially with kojic acid: a small amount on the inner arm, once a day for a few days.
2. Once or twice a day, on clean, dry skin: the serum under your moisturiser, the cream as your moisturiser.
3. Sunscreen every morning — tinted if you can, and on cloudy days too.
4. One new product at a time, two weeks apart.
5. Judge it at 8–12 weeks, not after a few days. That is how long the trials ran, and the point at which the 2026 consensus assesses a first treatment for melasma.
6. Stop if it stings, itches or reddens and does not settle. With kojic acid, a rash that appears after weeks of trouble-free use can be an allergy: stop and ask a pharmacist or doctor rather than pushing through.

What they combine well with

• Niacinamide. It acts on pigment transfer rather than production. Our Niacinamide Gel Moisturiser is 5%, the strength the trials used.
• Vitamin C. Our Vitamin C Serum uses ascorbyl glucoside, a stable form. Apply it in the morning, under sunscreen.
• Exfoliating acids. Kojic acid was trialled alongside glycolic acid. Add the Glycolic Acid Exfoliating Toner on a few evenings a week once your skin has settled — on different evenings from your dark-spot product at first.

Where to start

If your skin tolerates actives and your dark spots are sun spots or old marks, start with the Dark Spot Face Cream with Kojic Acid, after a patch test. If your skin is sensitive, or kojic acid has irritated you before, start with the Pigment Perfecting Serum under your usual moisturiser. Either way, the product that will make the biggest difference is the tinted SPF50 stick, every morning. The rest of the range for uneven tone is in our brightening and dark spot edit.

And if your patches are symmetrical, arrived with pregnancy or the pill, or keep coming back, see a dermatologist. That is melasma, and the treatments that work best for it — hydroquinone, the triple cream, tranexamic acid tablets — are on prescription for a reason.