Tag: vitamin K skincare

  • Dark Circles in Korea: A 0-5 Grade Scale in the Test Guideline, and No Claim Category in the Notified List (Skin Concern Series)

    Cover image for an article on dark circle ingredients in Korea. Annex 4 of the functional cosmetics notification lists six claim categories and the word dark circle does not appear in it; the nearest box is whitening with nine actives. Chapter 6 of the Korean MFDS guideline on test methods for substantiating claims instead writes down the procedure: the test site is the dark-circle area under the eye, melanin index is read with a Mexameter MX18 and lightness L star with a Chromameter CR-400, and at least twenty valid data sets are required. Dr. J Ingredient Notes.

    🇰🇷 한국어판

    Hello, this is Dr. J. Today I want to look at dark circle ingredients the way Korean regulators look at them — and at what the human studies actually moved.

    Two things surprised me. The word “dark circle” does not appear in Annex 4, the table that fixes actives and levels for notified functional cosmetics. And yet the Korean regulator wrote down how to measure one, down to a 0-5 grade scale that two experts apply by eye.

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    Primary sources

    📄 MFDS, Guideline on Test Methods for Substantiating Cosmetic Claims (Mar 2018, PDF, Korean)

    📄 Regulation on Functional Cosmetics Review, Annex 4 (Korea Law Service)

    📄 Phytonadione, retinol and vitamins C and E, 8 weeks (J Cosmet Dermatol 2004)

    📄 Vitamin C on dark circles, 6 months, split face (Skin Res Technol 2009)

    📄 U.S. FDA, Cosmetics Labeling Claims

    The guideline covers ten claims. Chapter 6 is dark circle relief.

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    Five lines, if you are in a hurry

    ● Annex 4 has six claim categories and dark circles is not one of them

    ● The nearest box is whitening, with nine notified actives — the pigment side

    ● Chapter 6 of the test guideline writes down how to measure the area under the eye

    ● It names the instruments and attaches a 0-5 expert grade scale

    ● But in the two eye-area studies, what moved was the vascular reading, not pigment

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    There is no box for it — Annex 4 and its six categories

    Annex 4 of the Regulation on Functional Cosmetics Review lists, for each claim category, the actives and the levels that let a manufacturer skip submitting new efficacy data. It is a shortcut list, not a safety list.

    There are six categories. I opened the original today and searched it: the word “dark circle” is not in the table.

    Category in Annex 4 What the notification fixes How to read it
    UV protection / tanning Actives and maximum levels Both the name and the number are set
    Whitening Nine actives (arbutin 2-5%, niacinamide 2-5%, and others) The nearest box to today’s topic
    Wrinkle improvement Four actives (retinol 2,500 IU/g, adenosine 0.04%, and others) The subject of the previous article
    Hair colour change Dyeing, bleaching and de-dyeing actives Hair, not skin
    Hair removal Thioglycolic acid and others Depilatories
    Acne-prone skin relief Salicylic acid 0.5% Covered in an earlier article
    Dark circles — There is no such category

    The nearest box is whitening, with nine actives

    Pigment is one of the reasons the under-eye area looks dark, and pigment is what the whitening box covers.

    Notified whitening actives (nine) Level
    Broussonetia extract 2%
    Arbutin 2-5%
    Ethyl ascorbyl ether 1-2%
    Oil-soluble licorice extract 0.05%
    Ascorbyl glucoside 2%
    Magnesium ascorbyl phosphate 3%
    Niacinamide 2-5%
    Alpha-bisabolol 0.5%
    Ascorbyl tetraisopalmitate 2%

    Two names in this table come back later in this article: ascorbyl glucoside and niacinamide.

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    What exists instead — Chapter 6 of the test guideline

    The MFDS guideline on test methods for substantiating claims (March 2018, document no. 0353-02) sets out how to test ten advertising claims. Chapter 6 is dark circle relief, and it was added in August 2014.

    Chapter Claim When it was added
    Ch. 1-3 Skin moisturising · Skin elasticity · Sebum control May 2012, original
    Ch. 4-5 Temporary cellulite reduction · Suitability for acne-prone skin Nov 2013
    Ch. 6 Dark circle relief Aug 2014 (B2-2014-4-003)
    Ch. 7-8 Blood circulation · Puffiness relief Dec 2015
    Ch. 9 Paraben-free 31 Mar 2017
    Ch. 10 Fine-dust protection 28 Mar 2018

    Chapter 6 — what is measured (the guideline’s own wording)

    1. “Melanin content of the skin is measured and the change in melanin index is evaluated.”
    2. “The L* value of the pigmented site is measured and the change is evaluated.”
    3. “The whole face is photographed at a fixed angle and distance, and Red, Green and Blue values are obtained with image analysis software to derive a quasi L* value.”
    4. “Two or more experts closely observe the dark-circle area and grade it according to the dark circle grade (Grade 0-5) in Table 1.”

    Chapter 6 — how it is run and how it is judged

    “The test site shall be the dark-circle area under the eye.”
    “The number of subjects shall be 20 or more so that statistical comparison is possible, securing valid data.”
    “Adults aged 20 or over shall be selected …”
    “After cleansing, subjects rest for 30 minutes under controlled conditions (20-24 °C, 40-60% RH) before measurement.”
    “Repeated measures ANOVA is evaluated for statistical significance at the 95% confidence interval (p<0.05).”
    “If one or more of the evaluation indices shows relief of dark circles after use of the test material, the product is judged to help relieve dark circles.”
    The study length is “recommended to be about 8 weeks”, and application follows the product’s own directions.

    Read closely, the judgement is on the permissive side: if one or more of the four indices improves, the product is judged to help.

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    The part that surprised me — a 0-5 grade scale for a shadow

    Chapter 6 attaches a table that two or more experts use to grade the area by eye. Here it is in full.

    Grade What the guideline writes (translated from the Korean text)
    0 No dark circle is perceived
    1 A faint purplish shadow in the inner lower eyelid, judged a dark circle because the colour deepens when the skin is pulled
    2 A purplish shadow clearly visible without pulling the skin, or mild pigmentation, or both together
    3 A deep purplish shadow, or moderate pigmentation in part of the area, or both together
    4 Uniform, strong pigmentation overall, sometimes seen above and below the eye at the same time
    5 Uniform and very strong pigmentation seen above and below the eye at the same time

    Grade 1 is the interesting one: the shadow counts as a dark circle because the colour deepens when the skin is pulled. Pull the skin and it darkens, and you are closer to a shadow; stays the same, and you are closer to pigment.

    Grades 4 and 5 say “above and below the eye at the same time”. Even within one claim, the scale looks at different places as it climbs.

    Evidence summary for dark circle ingredients. First, there is no dark-circle box in the notified list: the six categories are UV protection and tanning, whitening, wrinkle improvement, hair colour change, hair removal and acne-prone skin, and the nearest box is whitening with nine actives including niacinamide at two to five percent. Second, the test method is written down in Chapter 6 of the MFDS guideline, with the test site under the eye, melanin index by Mexameter MX18, lightness L star by Chromameter CR-400, photographs by Visia-CR, expert visual grading from zero to five, at least twenty valid data sets, adults aged twenty and over, twenty to twenty-four degrees and forty to sixty percent humidity with thirty minutes of rest, and repeated measures analysis of variance at p below 0.05. Third, two actives moved the vascular reading: in fifty-seven Japanese adults over eight weeks, an open-label gel with phytonadione two percent, retinol zero point one percent and vitamins C and E improved the vascular component in twenty-seven of fifty-seven, that is forty-seven percent, while pigmentation was not clearly removed. Fourth, two vitamin C forms split apart: in fourteen subjects over six months with a split-face vehicle control, sodium ascorbate ten percent showed a significantly smaller change in erythema index than the vehicle side, while ascorbyl glucoside showed no difference from vehicle in erythema, melanin or dermal thickness. Fifth, what was left out and why: niacinamide stopped at the notified two to five percent because no eye-area trial could be opened, a caffeine and vitamin K study used an eye pad rather than a cream, laser, filler, mesotherapy and peels are procedures, and a trademark-ingredient serum trial names ingredients that cannot be found on a label.

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    Two that moved the vascular reading — vitamin K and retinol

    57 Japanese adults with infraorbital dark circles and lower-eyelid wrinkles applied a gel twice daily for 8 weeks — the same length Chapter 6 recommends.

    The gel contained phytonadione (vitamin K1) 2%, retinol 0.1% and vitamins C and E at 0.1%.

    After 8 weeks the vascular component improved in 27 of the 57 (47%), and wrinkles decreased in some subjects. Pigmentation was not clearly removed.

    The weak points belong here too: the study was open label, and with four actives in one gel the shares cannot be separated.

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    Two vitamin C forms that split apart

    14 subjects with dark circles applied sodium ascorbate 10% under one eye and the vehicle under the other for 6 months.

    On the sodium ascorbate side, the change in erythema index was significantly smaller than on the vehicle side. Dermal thickness trended upward but did not reach significance.

    In the same study, ascorbyl glucoside showed no difference from vehicle in erythema index, melanin index or dermal thickness.

    They are both vitamin C derivatives, and ascorbyl glucoside is one of the nine notified whitening actives, at 2%. Being on the notified list and moving a number under the eye are two different things.

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    The one the notified list puts on the pigment side — niacinamide

    Niacinamide 2-5% sits in the whitening box, so a Korean product can carry a reviewed whitening claim with it.

    I could not open an eye-area trial for it as a primary source today, so this article stops at the notified level rather than implying more.

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    The five in one table

    Ingredient People and time Design What was measured Result
    Vitamin K (phytonadione 2%) 57 Japanese adults · 8 weeks Open label · twice daily Vascular score, pigmentation, wrinkles Vascular score improved in 27 (47%)
    Retinol 0.1% Same study In the same gel Same measures Wrinkles decreased in some subjects
    Sodium ascorbate 10% 14 subjects · 6 months Split face · vehicle control Erythema index, melanin index, dermis Change in EI significantly smaller than vehicle
    Ascorbyl glucoside Same study Same design Same measures No difference from vehicle
    Niacinamide 2-5% — — — Notified level for whitening, nothing more here

    Where each study is weak

    Ingredient Where it is weak
    Vitamin K and retinol Open label, with no placebo arm in the abstract. Four actives sat in one gel, so the shares cannot be separated. Pigmentation was not clearly removed
    Sodium ascorbate Only 14 subjects. No p value in the abstract, and the dermal thickening was not significant
    Ascorbyl glucoside Its concentration is not given in the abstract. The null result itself is clear
    Niacinamide No eye-area trial could be opened as a primary source today, so this article stops at the notified level

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    Korea, the United States and the EU

    None of the three keeps a list of actives for dark circles. What differs is whether the regulator writes down how to measure it.

    What a dark circle claim rests on Who writes the test method
    Korea No box in the notified list. The claim is substantiated afterwards (Cosmetics Act Art. 14) The government does — Chapter 6 names the instruments, the room conditions and a 0-5 expert grade scale
    United States There is no list of approved claims at all — “FDA does not have a list of approved or accepted claims for cosmetics” Nobody. The agency also states it has no authority to approve claims before marketing
    EU The six common criteria of Regulation (EU) No 655/2013 Nobody — only the conditions: “adequate and verifiable evidence” and “state of the art practices”

    For an exporter the practical line is short: in Seoul the question is how you measured it, in Brussels and Washington the question is what evidence you hold. Korea is unusual in writing the instruments, the room conditions and a grading table into a public document for a claim it does not pre-review.

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    Five things to check on a label

    ✔ Ask first what is dark — pigment, visible vessels, or a shadow

    ✔ In front of a mirror, pull the skin gently: if the colour deepens, you are closer to the shadow side (that is Grade 1’s own wording)

    ✔ A whitening functional claim means one of the nine notified actives, on the pigment side

    ✔ A “dark circle” claim is substantiated, not pre-reviewed — the procedure lives in Chapter 6

    ✔ Where an advertisement shows a number, look for how many people, how many weeks, and which index

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    One line

    Korea wrote the ruler and the grading table, but never opened a box for the claim — and the two eye-area studies moved the vascular reading rather than the pigment one.

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    What I left out, and why

    ✔ A caffeine 3% and vitamin K 1% study (Adv Biomed Res 2015, 11 women, 4 weeks) — the product was an eye pad, not a cream, and the report carries no figures or p values

    ✔ Laser, filler, mesotherapy, PRP and peels — procedures. On this topic they fill most of the search results

    ✔ A single-arm serum trial (J Clin Aesthet Dermatol 2022, 85 completers, 3 months, melanin index down 12.29%, p<0.05) — the only study here that measured melanin under the eye directly, but its actives are trade names that a reader cannot find on an ingredient list, there was no placebo arm, and the manufacturer funded it

    ✔ Mechanism paragraphs (vascular permeability, haemoglobin breakdown, melanosome transfer) — I did not open a primary review, so I did not write them

    ✔ Folk wisdom — “dark circles come from lack of sleep” and “tapping helps” have no primary source here

    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.

    📌 Related reading

    📌 Firmness actives in Korea: wrinkle is notified, elasticity is substantiated — Chapter 2 of the same guideline

    📌 Pores and sebum: the test method the regulator wrote down — Chapter 3 of the same guideline

    📌 Niacinamide: how much is enough — the notified 2-5% in detail

    📌 Not all vitamin C serums work — the two forms that split apart today

    📌 Retinol: start at 0.1% — the concentration that sat in today’s gel

    📄 References

    · Regulation on Functional Cosmetics Review, Annex 4 (Korea Law Service, accessed 22 Oct 2026)

    · Ministry of Food and Drug Safety, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising Claims (civil petitioner guide, Mar 2018, no. 0353-02), Chapter 6

    · Mitsuishi T, Shimoda T, Mitsui Y, Kuriyama Y, Kawana S. J Cosmet Dermatol 2004;3(2):73-75

    · Ohshima H, Mizukoshi K, Oyobikawa M, Matsumoto K, Takiwaki H, Kanto H, Itoh M. Skin Res Technol 2009;15(2):214-217

    · U.S. FDA, “Cosmetics Labeling Claims” (content current as of 21 Nov 2022) · Regulation (EU) No 655/2013 · Regulation (EC) No 1223/2009 Art. 14

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    This article summarises published research and Korean regulatory documents; it is information, not diagnosis or treatment. Annex 4 and Chapter 6 were read in the original today, and the quoted Korean passages are my translation of that text. Of the two eye-area studies, one was open label with four actives in a single gel and the other had 14 subjects and no p value in the abstract — both facts are in the tables above. Ingredient names and levels are written as criteria for choosing a product, not as a recommendation of any particular one.

    — Dr. J Ingredient Notes