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COSRX

COSRX The Alpha-Arbutin 2 Discoloration Care Serum

Ingredient analysis and how the ad lines read

Read on 2026-09-24

What is this product?

A Korean watery serum in a 50 ml dropper bottle, legally filed as a whitening functional cosmetic, built around four pigment actives placed together at 4 to 7 of 38 entries: niacinamide, tranexamic acid, acetyl glucosamine and alpha-arbutin, with ferulic acid and glutathione late in the list. The legal list prints alpha-arbutin at 2 percent; the bottle label adds tranexamic acid 3 percent, niacinamide 5 percent and NAG 2 percent. No fragrance entry or essential oil; ethanol and two silicones are present. Two four-week tests on 20 women report melanin -20.47% and visible spots -22.31% without a control arm, and a 33-person sensitive-skin patch test scored 0.00. Aimed at post-blemish marks and uneven tone.

What makes it different?

Alpha-arbutin at a legally printed 2 percent together with tranexamic acid, niacinamide and acetyl glucosamine in one filed whitening serum. Across the 16 other landed records for this brand, none carries alpha-arbutin, tranexamic acid or ferulic acid. It also shows a named-product sensitive-skin patch test scoring 0.00, while its spot tests lack a control arm and the label amounts for three actives are not in the legal list.

What is in it?

The full ingredient list as the brand publishes it, in the printed order. Each name links to what we know about that ingredient.

Key ingredientWorth a closer look

Ingredients with no mark are ones we found nothing notable about, and when marks overlap on one ingredient we show the caution first.

We could not place these in the list above: 소듐메틸스테아로일타우레이트

Did the ad claims hold up?

We checked 51 lines this product advertises against the ingredient list and public documents. 5 of them hold up. The rest are only partly right or have nothing behind them.

Claims translated from Korean, originals preserved.

backed by evidence5

  • Whitening functional product
    Korean original

    미백 기능성 제품

  • Human skin primary irritation test completed on sensitive skin
    Korean original

    민감성 피부 대상 인체 피부 일차자극 테스트 완료

  • Skin irritation index 0.00
    Korean original

    피부 자극 지수 0.00

  • Skin irritation degree: non-irritating
    Korean original

    피부 자극 정도 비(무)자극성

  • Whitening functional
    Korean original

    미백 기능성

likely, not proven12

  • #TroubleMarkCare
    Korean original

    #트러블흔적케어

  • Help for the post-breakout appearance
  • A fresh watery serum that quickly sinks in.
    Korean original

    빠르게 쏙 스며드는 산뜻한 워터리 세럼

  • A “multi-target solution” that comprehensively targets all stages of trouble turning into pigmentation with a combination of powerful key ingredients.
    Korean original

    강력한 핵심성분의 조합으로 트러블이 색소침착 되어가는 모든 단계들을 입체적으로 공략해주는 “멀티 타겟 솔루션”

  • Five ingredients that help with irritation relief and skin soothing/protection gently care for sensitized skin.
    Korean original

    자극 완화와 피부 진정 / 보호에 도움을 주는 5가지 성분이 민감해진 피부를 부드럽게 케어해줍니다.

  • Helps with moisture, moisturization and skin function improvement with 5 types of hyaluronic acid.
    Korean original

    5종 히알루론산 수분 보습 및 피부 기능 개선에 도움

  • Panthenol helps with skin irritation relief, moisture retention/moisturization.
    Korean original

    판테놀 피부 자극 완화, 수분유지/보습에 도움

  • Tocopherol helps with moisture retention/moisturization, skin irritation relief, and skin soothing.
    Korean original

    토코페롤 수분유지/보습, 피부자극 완화, 피부진정에 도움

  • Allantoin helps with irritation relief, skin soothing, and skin protection.
    Korean original

    알란토인 자극 완화와 피부 진정, 피부 보호에 도움

  • Madecassoside helps with skin irritation relief.
    Korean original

    마데카소사이드 피부 자극 완화에 도움

  • Watery formula that absorbs quickly and lightly without burden
    Korean original

    빠르고 산뜻하게 흡수되어 부담 없는 워터리 포뮬러

  • Removable sticker label that peels off cleanly*
    Korean original

    깔끔하게 떼어지는 리무버블 스티커 라벨*

partly backed22

  • #MarkBrighteningSerum
    Korean original

    #흔적미백세럼

  • A high-strength, high-concentration trouble mark brightening serum that cares for visible marks.
    Korean original

    눈에 보이는 흔적을 케어하는 고강도, 고함량 트러블 흔적 미백 세럼

  • Tranexamic Acid 3% + Niacinamide 5% + NAG 2%
  • Care for the appearance of dark spots
  • Powerful 6 key ingredients for trouble mark concerns.
    Korean original

    트러블 흔적고민을 위한 강력한 6가지 핵심성분

  • Irritation-relief care that calms even the most sensitive.
    Korean original

    예민함까지 진정시키는 자극 완화 케어

  • Soothing ingredient formula that relieves irritation concerns.
    Korean original

    자극 걱정 덜어내는 진정성분 처방

  • In just 4 weeks, unwanted visible mark concerns go DOWN.
    Korean original

    단 4주 만에 표면으로 드러나 보기 싫은 흔적고민 DOWN

  • * The area of melanin shown in red on the face decreased over 4 weeks, showing relief.
    Korean original

    * 안면부위 붉게 표시되는 멜라닌의 면적이 4주에 걸쳐 감소하여 완화된 모습

  • Skin surface melanin amount -20.47%
    Korean original

    피부 표면 멜라닌 양 -20.47%

  • In just 4 weeks, improve long-standing mottled spot marks.
    Korean original

    단 4주 만에 오랫동안 자리 잡은 얼룩덜룩 잡티흔적 개선

  • * The pigmentation area on the face decreased over 4 weeks, showing improvement.
    Korean original

    * 안면부위 색소침착 면적이 4주에 걸쳐 감소하여 개선된 모습

  • Visible old age spots and blemishes -22.31%
    Korean original

    육안으로 보이는 오래된 기미잡티 -22.31%

  • Test completed for suitability on acne-prone skin
    Korean original

    여드름성 피부 사용 적합 테스트 완료

  • Non-comedogenic test completed
    Korean original

    논코메도제닉 테스트 완료

  • After use, it helped improve visible old age spots and blemishes. 95%
    Korean original

    사용 후 육안으로 보이는 오래된 기미잡티 개선에 도움이 되었다. 95%

  • After use, it helped improve skin surface/inner melanin. 95%
    Korean original

    사용 후 피부 겉/속 멜라닌 개선에 도움이 되었다. 95%

  • After use, it helped improve skin tone (brightness). 95%
    Korean original

    사용 후 피부톤(밝기) 개선에 도움이 되었다. 95%

  • After use, skin feels smoother. 100%
    Korean original

    사용 후 피부가 매끄러워진 느낌이다. 100%

  • After use, spreadability is satisfactory. 100%
    Korean original

    사용 후 발림성이 만족스럽다. 100%

  • After use, absorption is satisfactory. 100%
    Korean original

    사용 후 흡수력이 만족스럽다. 100%

  • With a low-viscosity texture that cleanly sinks into the skin and finishes without stickiness, it's always zero burden regardless of skin type or season!
    Korean original

    피부에 깔끔하게 쏙 스며들어 끈적임 없이 마무리되는 저점도 제형으로 피부타입과 계절에 관계없이 언제나 부담 제로!

overstated ad line4

  • COSRX's carefully selected 6-ingredient formula that tightly cares for the mark formation mechanism definitely resolves the concern!
    Korean original

    흔적 발생 메커니즘을 빈틈없이 밀착 케어하는 코스알엑스가 엄선한 6가지 성분 설계 포뮬러로 확실하게 고민 해결!

  • High-strength mark care formula
    Korean original

    고강도 흔적케어 포뮬러

  • No worries about pore clogging even for sensitive acne-prone skin.
    Korean original

    예민한 여드름 피부도 모공 막힘 걱정 NO

  • Consumers' direct experience of amazing satisfaction
    Korean original

    소비자가 직접 경험한 놀라운 사용 만족도

no evidence3

  • 2025 Serum Director's Pie TOP of TOP
    Korean original

    2025 세럼 디렉터파이 TOP of TOP

  • Selected as 'Acne soothing & mark high-strength TOP' in Director's Pie channel content.
    Korean original

    디렉터파이 채널 콘텐츠 내 ‘여드름 진정 & 흔적 고강도 TOP 선정’

  • Director's Pie TOP of TOP Acne Soothing & Mark High-Strength
    Korean original

    디렉터파이 TOP of TOP 여드름 진정 & 흔적 고강도

says nothing5

  • Trouble mark concern care serum for everyone.
    Korean original

    모두를 위한 트러블 흔적 고민 케어 세럼

  • From the start to the end of mark formation!
    Korean original

    흔적발생의 시작부터 끝까지!

  • The answer to stubborn mark concerns is COSRX Trouble Mark Brightening Serum.
    Korean original

    고집스러운 흔적 고민의 해답은, 코스알엑스 트러블 흔적 미백 세럼

  • Clean COSRX
  • Happy-ending with COSRX Trouble Mark Brightening Serum!
    Korean original

    코스알엑스 트러블흔적미백세럼으로 해피-엔딩!

Each line is quoted as the brand published it, and each one was read on its own against the ingredient list and the documents the brand publishes.

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