Tag: vitamin C derivatives

  • Korea’s Nine Approved Brightening Actives: What the Human Studies Show for Melasma and Dark Spots

    Cover image for an article on the five ingredients to look for in melasma and dark spot care. Korea's functional cosmetics notification lists nine approved brightening actives with set concentrations, and this article reads the human studies for niacinamide, arbutin, magnesium ascorbyl phosphate and alpha-bisabolol, from Dr. J Ingredient Notes.

    🇰🇷 한국어판: 기미 화장품 성분 다섯 – 미백 고시 아홉 가지에서 고르는 법

    Hello, this is Dr. J. Today we are choosing brightening ingredients for melasma and dark spots the way a formulator does: from the regulation first, then from the human studies.

    Here is the part that surprises people outside Korea. In Korea, “brightening” is not a free marketing word. It is a functional claim, and there is an official list of actives with the amounts written next to them. The list has nine entries. I read the human evidence for each one, and I could open full abstracts for four. I will say that plainly as we go.

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    Primary sources

    📄 Regulation on Review of Functional Cosmetics, Annex 4 (MFDS notification) — the nine actives, their amounts, dosage forms and claim wording

    📄 Niacinamide and cutaneous pigmentation (Hakozaki 2002)

    📄 Arbutin 2.51% cream, 8 weeks (Morag 2015)

    📄 Magnesium ascorbyl phosphate and melanogenesis (Kameyama 1996)

    📄 Alpha-bisabolol in Asian women (Lee 2010)

    📄 EU SCCS opinion on alpha-arbutin and beta-arbutin (SCCS/1642/22, 31 January 2023)

    The Korean annex opens directly as an attachment file. It is worth opening once: the amounts are printed in a single line each, so you can hold the page next to a product’s back label.

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    In short, five lines

    ✔ Korea’s functional list has nine brightening actives, with the amounts fixed

    ✔ I could open full human-study abstracts for four of them

    ✔ Niacinamide separated from vehicle at 4 weeks, arbutin at 8 weeks

    ✔ The alpha-bisabolol trial was run on the back, not the face

    ✔ Tranexamic acid is not on the list, and its topical trials run 12 weeks

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    Nine actives, and what the amounts actually mean

    The annex is titled “Types of functional cosmetics for which data submission is omitted”. Read that title before you read the numbers. The concentrations are not upper safety limits. They are the amounts at which a company does not have to submit new efficacy data, because the authority has already accepted the evidence for that active at that amount.

    No. Active Amount Study opened here
    1 Broussonetia (mulberry) extract 2% —
    2 Arbutin 2–5% Morag 2015 · 102 women, 8 weeks
    3 Ethyl ascorbyl ether 1–2% —
    4 Oil-soluble licorice extract 0.05% —
    5 Ascorbyl glucoside 2% —
    6 Magnesium ascorbyl phosphate 3% Kameyama 1996 · 19 of 34
    7 Niacinamide 2–5% Hakozaki 2002 · 18 and 120 people
    8 Alpha-bisabolol 0.5% Lee 2010 · 28 women, 8 weeks
    9 Ascorbyl tetraisopalmitate 2% —

    The annex also fixes the dosage forms — lotion, liquid, cream and sheet mask — and the exact claim wording, which translates as “helps brighten the skin”. Even the directions are written down: apply an appropriate amount and spread evenly, and for a sheet mask, remove the sheet after 10 to 20 minutes and spread what is left. A product that follows all of this files a report instead of a full review.

    The five rows marked “—” are the ones where I could not open a human study abstract today. That is not the same as saying no study exists. It is a note about what I verified, and I would rather write it than leave you guessing.

    Evidence figure listing what the sources say about five brightening ingredients. First, Annex 4 of Korea's Regulation on Review of Functional Cosmetics lists nine approved actives: mulberry extract 2 percent, arbutin 2 to 5 percent, ethyl ascorbyl ether 1 to 2 percent, licorice extract 0.05 percent, ascorbyl glucoside 2 percent, magnesium ascorbyl phosphate 3 percent, niacinamide 2 to 5 percent, alpha-bisabolol 0.5 percent and ascorbyl tetraisopalmitate 2 percent, in lotion, liquid, cream and sheet mask forms. Second, the niacinamide study had 18 people use 5 percent and vehicle in a paired design and 120 tanned people use three treatments, with pigmentation falling after 4 weeks, Hakozaki 2002. Third, the arbutin 2.51 percent cream study randomised 102 women to 54 active and 48 placebo for 8 weeks, with lightening in 75.86 percent of melasma cases, Morag 2015. Fourth, magnesium ascorbyl phosphate improved 19 of 34 people with pigmentation and only 3 of 25 with normal skin, Kameyama 1996. Fifth, alpha-bisabolol was applied for 8 weeks on the back rather than the face by 28 women, Lee 2010.

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    The four, in one table — including what each was compared with

    A percentage means very little on its own. What it was measured against is where the value sits: the same cream without the active, a different product, untreated skin, or simply the starting point.

    Active Study People · duration Compared with What was found
    Niacinamide 5% Hakozaki et al. 2002 18 with hyperpigmentation vehicle moisturiser, paired on the same person Significant drop in pigmentation and rise in lightness at 4 weeks
    Niacinamide 2%
    with sunscreen
    same paper 120 with facial tanning vehicle, sunscreen alone Better than vehicle on skin colour measures
    Arbutin 2.51% Morag et al. 2015 102 women · 8 weeks
    54 active · 48 placebo
    placebo cream, double-blind Lightening in 75.86% of melasma, 56.00% of solar lentigo
    placebo figures not in the abstract
    Magnesium ascorbyl phosphate Kameyama et al. 1996 34 with pigmentation
    duration not in the abstract
    baseline pigmentation 19 of 34 improved significantly · 3 of 25 with normal skin
    Alpha-bisabolol
    concentration not in the abstract
    Lee et al. 2010 28 women · 8 weeks · back vehicle cream on the same women Significant lightening in most subjects
    Tranexamic acid
    not on the list
    covered in guide 9 trials run 12 weeks varies by trial Topical-only results were not statistically clear

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    Niacinamide 2–5% — the point where it separated from vehicle was 4 weeks

    Hakozaki 2002 carried two human trials in one paper. In the first, 18 people with facial hyperpigmentation used a 5% niacinamide moisturiser and a vehicle moisturiser in a paired design — both products on the same face, one per side. In the second, 120 people with facial tanning were each assigned two of three treatments: vehicle, sunscreen, or 2% niacinamide plus sunscreen.

    Changes were quantified by computer analysis of high-resolution facial images and by visual grading. After 4 weeks, niacinamide significantly decreased hyperpigmentation and increased skin lightness compared with vehicle alone. The paired design is the part I like: season, sleep and sun exposure are held constant because both sides belong to the same person.

    The same paper ran cell work. Niacinamide gave 35–68% inhibition of melanosome transfer in a keratinocyte and melanocyte co-culture, and reduced pigmentation in a reconstructed epidermis model. It had no effect on mushroom tyrosinase activity or on melanin production in cultured melanocytes. Worth keeping those in their own lane: a co-culture is not a face, and I would not carry the 35–68% figure over to what happens on your cheek.

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    Arbutin 2–5% — 102 women, 8 weeks, and a different number in the EU

    Morag 2015 was a double-blind, placebo-controlled randomised trial in 102 women aged 26 to 55 with melasma or solar lentigo. Fifty-four used a cream containing 2.51% arbutin twice daily for 8 weeks; 48 used placebo.

    Lightening was seen in 75.86% of the melasma cases and 56.00% of the solar lentigo cases. The placebo-arm figures are not given in the abstract, so I have not carried them over. Read the percentage as “how many in the active arm showed lightening”, not as “how much better than placebo”.

    Europe looked at the same molecule from the safety side, which is a different question from efficacy. The SCCS adopted its opinion on 31 January 2023.

    What the number decides Korea · Annex 4 EU · SCCS/1642/22 (2023)
    Nature of the figure efficacy data can be omitted safety assessment
    Arbutin (beta) 2–5% safe in face creams up to 7%
    Alpha-arbutin not named in the annex safe in face creams up to 2%, body lotions up to 0.5%
    Hydroquinone content not the subject of this annex “as low as possible… not higher than the unavoidable traces in both arbutins”
    LOQ 3 ppm · LOD 1 ppm

    So a Korean product and a European product can both be correct and still print different percentages, because the two numbers answer different questions. And on a back label, “arbutin” and “alpha-arbutin” are two different names — the annex lists the first one. Guide 15 goes through that comparison in detail.

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    Vitamin C derivatives — 19 of 34, and only 3 of 25

    Four of the nine entries are vitamin C derivatives: ethyl ascorbyl ether 1–2%, ascorbyl glucoside 2%, magnesium ascorbyl phosphate 3% and ascorbyl tetraisopalmitate 2%. Pure ascorbic acid is unstable in a finished formula, so the molecule is modified and the skin’s enzymes are expected to release it.

    Of those four, the one I could open was magnesium ascorbyl phosphate. Kameyama 1996 reported that 19 of 34 patients with chloasma or senile freckles showed significant lightening. In the same paper, among 25 people with normal skin, only 3 did.

    Put those two numbers side by side and you get a way to read them: this is an ingredient that earns its place where the pigment already is. Expect it to work on the dark patch rather than to change your overall complexion. The trial duration is not stated in the abstract, which is worth knowing before you set a deadline for it.

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    Alpha-bisabolol 0.5% — the trial was not run on faces

    Lee 2010 tested a base cream containing alpha-bisabolol on 28 female subjects, applied once a day for 8 weeks. The application site was pigmented skin on the back, and the same women also applied a vehicle control cream. Results were assessed by clinical and biophysical methods, and after 8 weeks most subjects showed significant lightening.

    Two honest notes. The concentration of alpha-bisabolol in the cream is not given in the abstract, and the back is not the face: thicker stratum corneum, different sun exposure, different pigment history. The annex figure of 0.5% is what Korea accepted for the claim; the trial figure is simply not stated. Knowing that keeps the expectation the right size.

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    The one that is not on the list — tranexamic acid

    Tranexamic acid does not appear among the nine. A Korean product carrying the brightening claim with tranexamic acid has therefore been through an individual review with its own safety and efficacy dossier, rather than the report route that the listed actives allow.

    The trials are built around 12 weeks, and when the topical route is pooled on its own the result was not statistically clear. Guide 9 sets out those numbers, including the confidence interval, and it is the honest place to start if a tranexamic acid serum is already in your routine.

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    What is not in this article, and why

    ✔ Comparisons with hydroquinone or prescription creams — a cosmetics article should not line itself up against a drug

    ✔ Laser and chemical peel trials — procedures are a separate conversation from ingredients

    ✔ Retinol for pigmentation (Kafi 2007) — I opened the abstract and it reports fine wrinkles and collagen markers, with no pigmentation outcome, so it is out

    ✔ Mechanism paragraphs — where I could not open the review, I stopped at what the abstract itself states

    ✔ Claims that circulate online — “vitamin C erases melasma”, “use brighteners at night only” — no primary source, so no sentence

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    Four things to check when you buy

    ✔ Whether the carton carries the functional cosmetics mark, with the claim wording printed underneath in the same size or larger

    ✔ Which of the nine names appears in the ingredient list

    ✔ Whether the format is a lotion, liquid, cream or sheet mask

    ✔ Whether there is enough product for 4 to 12 weeks, since that is the length the trials ran

    Whichever active you choose, daytime sunscreen travels with it. Pigment darkens again in sunlight, and the 120-person arm of Hakozaki 2002 was itself run on top of a sunscreen. Guide 11 covers how to read SPF and PA labels.

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    One line

    Pick a name from the list of nine, give it 4 to 12 weeks, and wear sunscreen while you do.

    The next guide takes on organic and natural cosmetic labelling — what those words are allowed to certify under the Korean standard.

    📌 Related guides

    📌 Niacinamide: How Much Is Enough (Guide 2)

    📌 Arbutin vs Alpha-Arbutin: Korea’s 2–5% and the EU limits (Guide 15)

    📌 Tranexamic Acid Cream: What the Melasma Trials Found (Guide 9)

    📌 Adenosine 0.04%: Who Decided That Number (Guide 12)

    📌 How to Read a Korean Cosmetic Ingredient List (Guide 14)

    📌 Sunscreen SPF and PA: How to Read the Numbers (Guide 11)

    About the author · Dr. J

    MS in Veterinary Medicine, PhD in Life Sciences. I worked as a researcher at the Korea Research Institute of Bioscience and Biotechnology (KRIBB) and now run Beaurea, a cosmetics manufacturing company, where I write the formulas myself. This blog reads the research papers and the regulatory documents and turns them into plain-language criteria for choosing ingredients. I don’t recommend specific products here – only criteria that apply to any product.

    📄 References

    · Regulation on Review of Functional Cosmetics, Annex 4 — Types of functional cosmetics for which data submission is omitted (MFDS notification)

    · Hakozaki T, Minwalla L, Zhuang J, et al. Br J Dermatol 2002;147(1):20-31

    · Morag M, Nawrot J, Siatkowski I, et al. J Cosmet Dermatol 2015;14(3):185-190

    · Kameyama K, Sakai C, Kondoh S, et al. J Am Acad Dermatol 1996;34(1):29-33

    · Lee J, Jun H, Jung E, et al. Int J Cosmet Sci 2010;32(4):299-303

    · SCCS Opinion on alpha-Arbutin and beta-Arbutin, SCCS/1642/22, adopted 31 January 2023

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    This article summarises a public regulation and published research. It is information, not a diagnosis or a treatment plan. The figures are as written in the notification and in each abstract, and results differ from person to person. If a pigment change worries you, please speak with a professional.

    — Dr. J Ingredient Notes