Tag: sebum control

  • Pores and Sebum in Korean Cosmetics: Five Ingredients, and the Test Method the Regulator Wrote Down

    Cover image for an article on pore and sebum claims in Korean cosmetics. Korea's functional cosmetic notice fixes ingredients and percentages for whitening with nine entries, wrinkles with four and acne with one, and it has no pore or sebum entry at all. A separate guideline from the Ministry of Food and Drug Safety, the Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising issued in March 2018, sets out ten claim types, and chapter three is sebum secretion control. A Sebumeter tape is pressed on the skin for thirty seconds and read as sebum per unit area in micrograms per square centimetre, with casual sebum level and sebum excretion rate measured separately. Pores are not among the ten. The five ingredients chosen here are niacinamide at two percent, green tea at five percent, L-carnitine at two percent, guava leaf at six percent and salicylic acid at zero point five percent, which is the notified acne ingredient. Cover image for Dr. J Ingredient Notes.

    🇰🇷 한국어판

    Hello, this is Dr. J. Today we look at the five ingredients worth knowing for oily skin and visible pores — chosen, in every case, from a human study that actually measured sebum.

    Here is the surprise. In Korea, “pores” is not one of the claims the regulator has written a test method for. “Sebum secretion control” is — down to the instrument, the number of seconds and the unit.

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    The primary sources

    📄 MFDS, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (March 2018, PDF, Korean)

    📄 Green tea, split-face study (Hippokratia 2013;17(1):64-67)

    📄 L-carnitine and EGCG (J Cosmet Dermatol 2023)

    📄 Regulation (EC) No 655/2013, common criteria

    Chapter 3 of the Korean guideline sets out the sebum procedure itself — the device, the thirty seconds, the unit, and the two values that are measured separately.

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    In five lines

    ✔ Korea’s functional-cosmetic notice has no pore or sebum entry

    ✔ Yet a separate guideline sets out how sebum is measured — chapter 3 of ten

    ✔ Three ingredients here have measured sebum numbers

    ✔ One more study measured the nose and the forehead apart

    ✔ What the studies measured is sebum, not pore size

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    What Korea’s notified list does fix

    Korea’s Regulation on Functional Cosmetic Review carries an annex that fixes ingredient names and percentages. Formulate to that line and you are excused from filing fresh efficacy data — which also means the state has drawn the boundary of each claim.

    Claim What the annex fixes How to read it
    Whitening Nine ingredients with percentages (arbutin 2–5%, niacinamide 2–5%, and others) Both the name and the number are set
    Wrinkle improvement Four ingredients (retinol 2,500 IU/g, adenosine 0.04%, and others) The same
    Acne-prone skin relief One ingredient — salicylic acid 0.5% This is where blocked pores lead
    Pores and sebum No entry at all “Pore minimising” and “sebum control” have not been reviewed as claims

    That is not a ban. It means no authority has signed off on the wording. The same gap appeared in our piece on sensitive skin — but with pores and sebum there is a second document to open.

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    The claim without a method, and the claim with one

    The Ministry of Food and Drug Safety publishes a separate guidance document, the Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (March 2018, guidance 0353-02). It gives each claim type its own chapter. There are ten.

    Chapter Claim Chapter Claim
    1 Skin moisturisation 6 Dark circle improvement
    2 Skin elasticity improvement 7 Skin blood circulation
    3 Sebum secretion control 8 Puffiness relief
    4 Temporary cellulite reduction 9 Paraben-free
    5 Suitable for acne-prone skin 10 Fine-dust protection

    Pores are not among the ten. The word appears once, in a footnote to chapter 5 that defines a comedo as a small sac formed when the opening of a sebaceous gland is blocked.

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    What chapter 3 actually says

    “A Sebumeter® is used. When the Sebumeter®, fitted with a special opaque plastic tape, is pressed on the skin with slight pressure for 30 seconds to collect sebum, the increase in the transparency of the tape is turned into a figure shown on the device, and that figure represents the amount of sebum per unit area (µg/cm²) collected.” — our translation of the Korean guideline, chapter 3

    What As the guideline sets it
    Device Sebumeter® — reads how far an opaque tape turns transparent
    Time 30 seconds of slight pressure on the skin
    Unit Sebum per unit area, µg/cm²
    Casual sebum level Measured as soon as the volunteer arrives, without washing — what has pooled on the skin
    Sebum excretion rate (SER) Measured after everyone washes with the same cleanser — how fast sebum returns
    Schedule A fixed body site, measured before and after application of the test material

    The split matters. “There is a lot of oil sitting there” and “oil comes back quickly” are different statements, and most of the studies below measured the second one.

    Evidence summary for an article on pore and sebum claims in Korean cosmetics, in five cards. First, what Korea's notified list leaves out: the functional cosmetic notice fixes ingredients and percentages for whitening with nine entries, wrinkles with four and acne with one, there is no pore or sebum entry in that table, and so pore minimising and sebum control are not claims a Korean authority has reviewed, which does not mean a brand cannot print them. Second, the test method is written down: the Ministry of Food and Drug Safety guideline on test methods for substantiating cosmetic labelling and advertising, issued March 2018 as guidance 0353-02 by the National Institute of Food and Drug Safety Evaluation, sets out ten claim types each with its own chapter, chapter three is sebum secretion control, a Sebumeter tape is pressed on the skin for thirty seconds and read as sebum per unit area in micrograms per square centimetre, casual sebum level and sebum excretion rate are measured separately, and pores are not among the ten. Third, three ingredients with sebum numbers: niacinamide two percent in Draelos 2006, where one hundred Japanese women over four weeks showed sebum excretion rate down twenty one point eight percent against ten point seven percent on placebo, while in the same paper thirty United States women over six weeks did not reach significance, so the two groups parted; green tea five percent in Mahmood 2013, where twenty two men over sixty days applied the product to one cheek against a placebo cheek and sebum was about twenty seven percent lower with a p value of zero point zero zero six zero; and L-carnitine two percent with epigallocatechin gallate five percent in Detudom 2023, where ninety subjects over four weeks showed falls in all three arms with p below zero point zero one, although there was no placebo arm. Fourth, nose and forehead measured apart: a guava leaf six percent toner in Pongsakornpaisan 2019, with twenty one subjects over twenty eight days in a split face single blind comparison against the base toner, measured with Sebutape on the forehead and on the nose, giving forehead thirteen point one zero plus or minus three point six seven percent with P below zero point zero five and nose twenty one point four three plus or minus three point two one percent with P below zero point zero zero one, parting from week three. Fifth, who writes the test method: in Korea a government guideline names ten claim types and the procedure for each, down to the thirty second reading; in the European Union, Regulation (EC) No 655/2013 says evidence shall take into account state of the art practices, and the Commission's technical document on cosmetic claims asks for methods which are reliable and reproducible while naming no particular test; in the United States the Food and Drug Administration states that it does not have a list of approved or accepted claims for cosmetics, and the same salicylic acid for acne sits at zero point five to two percent in an over the counter drug monograph. All statements come from the sources named on each card.

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    Five ingredients in one table — including where each is weak

    Ingredient Study People · duration Compared with What was measured Where it is weak
    Niacinamide 2% Draelos 2006
    J Cosmet Laser Ther 8(2)    		 100 Japanese women · 4 weeks
    30 US women · 6 weeks    		 Placebo Sebum excretion rate down 21.8% (placebo 10.7%)
    At 2 weeks 21.3% (placebo 8.6%)    		 The two groups parted — the US arm did not reach significance
    Green tea 5% Mahmood 2013
    Hippokratia 17(1)    		 22 men (22–28) · 60 days One cheek against a placebo cheek About 27% lower (p=0.0060)
    Sebumeter SM 815    		 22 men, and the raw µg/cm² values appear only in the figures
    L-carnitine 2%
    EGCG 5%    		 Detudom 2023
    J Cosmet Dermatol 22(11)    		 90 subjects, three arms · 4 weeks The three active arms against each other All three arms fell (p<0.01)
    The combination beat L-carnitine alone (p=0.009)    		 No placebo arm · age and sex are not in the abstract
    Guava leaf 6% Pongsakornpaisan 2019
    J Cosmet Dermatol 18(6)    		 21 subjects · 28 days Half the face against the base toner (single-blind) Sebutape®
    Forehead 13.10±3.67% (P<0.05) · nose 21.43±3.21% (P<0.001)
    The nose parted from week three    		 21 subjects, and the abstract alone does not settle whether the percentages are against baseline or between arms
    Salicylic acid 0.5% Korean notice, Annex 4 — — The notified ingredient for acne-prone skin relief Regulatory ground, not a sebum measurement

    Read the table across and the yardstick appears. Numbers of people, duration and comparator give the same percentage a different weight.

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    The one ingredient Korea fixed by notice

    Item As the notice sets it
    Ingredient and level Salicylic acid 0.5%
    Form Solution · lotion · cream
    Claim “Helps relieve acne-prone skin”
    Directions Apply an appropriate amount and rinse off thoroughly with water straight away
    Age restriction
    Safety standards, Annex 2    		 0.5% as salicylic acid, not for use in products for infants or products specifically labelled as usable by children aged 13 or under (shampoo excepted)

    Note the rinse-off in the directions. The form Korea reviewed is not a leave-on product. In the United States the same acid for acne is not a cosmetic ingredient at all — see the next table.

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    Who writes the test method — Korea, the EU and the US

    Korea EU United States
    List of claims For functional cosmetics the notice fixes ingredient and percentage; other claims appear on a separate substantiation list Not a list but six common criteria (Reg. (EC) No 655/2013) “FDA does not have a list of approved or accepted claims for cosmetics.“
    Test method Written out claim by claim — ten chapters, chapter 3 being sebum secretion control (Sebumeter® · 30 seconds · µg/cm²) Evidence “shall take into account state of the art practices“. The Commission’s technical document asks for “methods which are reliable and reproducible” and names no particular test No prescribed method. Labelling, including claims, “must be truthful and not misleading“
    Salicylic acid for acne A cosmetic — notified functional ingredient at 0.5% Handled inside the cosmetics regulation An OTC drug — 21 CFR 333.310 sets it at 0.5 to 2 percent
    Pores Neither in the notice nor among the ten test methods We found nothing set aside for it The same

    Put the three side by side and the axis is clear. Korea writes down what to measure and how; the EU sets a condition — reliable, reproducible, state of the art — and leaves the method to the field; the United States keeps no approved list at all. The clearest illustration is that the same salicylic acid is a cosmetic ingredient in Seoul and a drug ingredient in Washington.

    For a brand selling into Korea, that has a practical edge: the procedure your sebum claim will be read against is a public document, and it is specific enough to design a study from.

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    Four things to check on the box

    ✔ “Pore minimising” is not a reviewed claim — look for the number and the source

    ✔ What the studies measured is sebum, not pore diameter

    ✔ Check how many people and for how long — 21 and 100 are not the same weight

    ✔ Check whether there was a placebo arm — in one of these studies there was not

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    One line

    Pores have no measuring stick yet; sebum has one. Start with the side that carries numbers.

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    What I did not use, and why

    ✔ Trials that measured pore size — none of the human cosmetic studies I opened measured pores directly

    ✔ Procedures — randomised trials of botulinum toxin or microneedling for pores belong to a different article

    ✔ Retinol and pores — I opened two retinol trials; neither abstract reported a pore endpoint, and one compared against a prescription drug

    ✔ Folk claims — “pores never shrink once enlarged”, “cold water closes pores”: no primary source

    ✔ A fresh reading of the niacinamide paper — the literature databases were rate-limited on the day of writing, so the figures come from an earlier piece in which the full text was read

    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 posts

    📌 Niacinamide: How Much Is Enough (Ingredient Guide 2) — the first ingredient here

    📌 Salicylic Acid (BHA): 0.5% vs 2%, Explained (Guide 8) — the notified 0.5% in full

    📌 AHA vs BHA: Is Glycolic Acid an AHA? (Guide 13) — the blocked-keratin side

    📌 How to Read a Korean Cosmetic Ingredient List (Guide 14) — finding the names on the pack

    📄 Sources

    · MFDS, Guideline on Test Methods for Substantiating Cosmetic Labelling and Advertising (civil-petition guidance 0353-02, March 2018), chapter 3

    · Regulation on Functional Cosmetic Review, Annex 4 · Regulation on Safety Standards for Cosmetics, Annex 2

    · Draelos ZD, Matsubara A, Smiles K. J Cosmet Laser Ther 2006;8(2):96-101

    · Mahmood T, Akhtar N, Moldovan C. Hippokratia 2013;17(1):64-67

    · Detudom P et al. J Cosmet Dermatol 2023;22(11):3058-3064 · Pongsakornpaisan P et al. ibid. 2019;18(6):1737-1741

    · Regulation (EC) No 655/2013, Annex (common criteria) · European Commission, Technical document on cosmetic claims

    · U.S. FDA, “Cosmetics Labeling Claims” (current as of 21 November 2022) · 21 CFR 333.310

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    This article summarises published studies and regulatory documents and is not a substitute for diagnosis or treatment. The Korean legal database was unavailable on the day of writing, so the notice figures come from earlier pieces in which the originals were read, and the niacinamide paper was not reopened. Translations of the Korean guideline are mine. Ingredient names and concentrations are given as criteria for choosing a product, not as a recommendation of any particular one.

    — Dr. J Ingredient Notes

  • Niacinamide: 5% Is Enough – What Each Concentration Has Actually Shown (Ingredient Encyclopedia 2)

    Niacinamide: 5% is enough - human studies ran at 2-5%, Korea's whitening functional range is 2-5%, no evidence 10% or 20% works better, Dr. J Ingredient Notes cover

    🇰🇷 이 글의 한국어판 → 한국어판

    Hello, I’m Dr. J.
    In Korea you can hardly walk past a serum shelf without seeing niacinamide on the label.
    It sits in most products approved here as brightening functional cosmetics.

    The number next to it keeps changing, though: 2%, 5%, 10%, 20%.
    Does a bigger number buy you more?
    Here is what the human studies actually support.

     

    The short version

    ✔ Niacinamide is a form of vitamin B3. One ingredient works on dark spots, pores, acne, redness, fine lines and the skin barrier
    ✔ The human studies ran at 2-5%, and Korea’s brightening functional range is also 2-5%
    ✔ No head-to-head human study shows 10% or 20% doing more. The chance of flushing does go up
    ✔ Morning and night are both fine, and it layers with retinol, vitamin C and acids
    ✔ Expect the first change around week 4 and a clear one at 8-12 weeks. Consistency matters more than strength
     

    What the research confirms – five jobs, one ingredient

    Niacinamide by concentration - 2% less sebum (Draelos 2006), 4% acne (Shalita 1995) and melasma (Navarrete-Solis 2011), 5% pigment, lines and redness (Bissett 2005, Hakozaki 2002), 10% no added benefit, 20% flushing
    · Dark spots — it blocks the hand-off of melanin to skin cells. It leaves the pigment-making enzyme alone, which is why it is gentle. Blotches faded over 8 weeks at 5%
    · Fine lines, redness, elasticity — 50 people used 5% on one half of the face and a plain cream on the other for 12 weeks. Fine lines, blotches, red spots, sallowness and elasticity all improved
    · Acne — a 4% gel matched a 1% clindamycin (antibiotic) gel over 8 weeks in 76 people
    · Sebum and pores — 2% for 4 weeks lowered sebum output. Less oil, less prominent pores
    · Barrier and dryness — it raises ceramide synthesis, so the skin loses less water. That is why it buffers a retinol or acid routine

    There is a melasma study too.
    4% niacinamide matched 4% hydroquinone with fewer side effects (27 people, 8 weeks).

     

    Choosing the number: 2, 5, 10 or 20%

    · 2% — the sebum and pore studies. A sensible starting point for sensitive skin
    · 4% — the acne and melasma studies
    · 5% — pigment, fine lines and redness. This is the reference point
    · 10% — no human comparison showing it beats 5%. More people report flushing
    · 20% — it exists on shelves, the evidence does not, and stinging is common

    That warm flush some people feel comes less from niacinamide itself than from nicotinic acid left in the raw material.
    A safety review of high-purity material (CIR) found no irritation even at 10%.
    Still, nothing shows that more is better, so 5% used for a long time is the path the research supports.

     

    Three things to check on the label

    ✔ Is there a number? “Contains niacinamide” can mean 0.5%
    ✔ A brightening functional claim (Korea) means 2-5% is definitely in there. It does not mean high strength
    ✔ If your face flushes, drop the strength or change products. Purity differs, so two 5% products can feel different
     

    When to use it, and what it layers with

    ✔ Morning and night — it is stable in light. Apply at the serum step, moisturiser on top
    ✔ With retinol → yes. It cushions the dryness and stinging of the break-in weeks
    ✔ With vitamin C → yes. The “never together” rule traces back to a 1960s solution experiment, not to modern formulas
    ✔ With AHA or BHA → yes. Applied after an acid it helps the barrier recover
    ✔ Give it 4 weeks, then keep going to 8-12 — the pigment-transfer block reverses within days of stopping, so it is an ingredient you stay on

    🧪 Check niacinamide pairings in the ingredient checker

     

    One line

    Niacinamide: 5%, morning and night, 8-12 weeks.
    It covers dark spots, pores, redness and the barrier at once and gets along with everything else, which makes it a good default serum in a routine.

    ▶ Ingredient encyclopedia 1: Retinol: Start at 0.1% – How to Read the Concentration Numbers
    ▶ Ingredient encyclopedia 3: Bakuchiol vs Retinol – What a 44-Person Trial Found
    ▶ Earlier post: Skincare Ingredient Compatibility Chart – What to Layer and What to Split
    ▶ Earlier post: Not All Vitamin C Serums Work – 3 Conditions the Research Says You Need
    🇰🇷 이 글의 한국어판 → 한국어판

    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
    1. Korea MFDS, Regulation on the Review of Functional Cosmetics, Table 4 — brightening: niacinamide 2-5%
    2. Bissett DL et al. Dermatologic Surgery 2005;31:860-865 — 5%, 50 subjects, 12 weeks, split-face
    3. Hakozaki T et al. British Journal of Dermatology 2002;147:20-31 — melanosome transfer reduced 35-68%, 5% for 8 weeks
    4. Shalita AR et al. International Journal of Dermatology 1995;34:434-437 — 4% vs 1% clindamycin, 76 subjects, 8 weeks
    5. Draelos ZD et al. Journal of Cosmetic and Laser Therapy 2006;8:96-101 — 2%, sebum output
    6. Navarrete-Solís J et al. Dermatology Research and Practice 2011 — 4% vs 4% hydroquinone, 27 subjects, 8 weeks
    7. Tanno O et al. British Journal of Dermatology 2000;143:524-531 — ceramide and barrier lipid synthesis

    ※ This article is general information. Results vary with individual skin. It does not recommend or criticise any specific product. If you are being treated for a skin condition, talk to your dermatologist first. The author runs a company that manufactures and sells cosmetics.