Regulation
Reading a Japanese cosmetics ingredient list: a translation primer
A practical primer on decoding Japanese ingredient lists — JIS naming conventions, katakana transliterations, and how to map them to international INCI names.
Japanese cosmetics ingredient labels look familiar at first glance — a list of ingredients in descending order of weight — but the naming conventions have their own logic. For an overseas buyer comparing a Japanese formulation to its INCI-labeled counterpart elsewhere, mismatches are common. This is a primer on how Japanese ingredient lists are built and how to translate them.
The regulatory baseline: JIS naming
Japanese cosmetics are required to use Japanese Industrial Standards (JIS) nomenclature on the ingredient list, drawing from the Japanese Cosmetic Ingredient Codex (化粧品表示名称). For many ingredients, the JIS name aligns closely with INCI — water is 水 (mizu), glycerin is グリセリン, for example.
For other ingredients, the JIS name is a Japanese translation of the INCI name rather than a direct transliteration. Tocopherol, for instance, appears as トコフェロール on Japanese labels — a direct katakana equivalent — but vitamin C derivatives may appear under Japanese-specific names like アスコルビン酸グルコシド (ascorbyl glucoside).
Katakana transliteration patterns
Most imported ingredient names are transliterated into katakana — the Japanese syllabary used primarily for foreign words. The transliteration follows predictable patterns once you know them: final "l" sounds become ル, "r" sounds become ラリルレロ depending on the vowel, "c" before a vowel typically becomes a K sound.
Common transliteration traps include silent letters in the English original being voiced in Japanese (gel → ジェル, not ジェ), and ingredient names that are partially translated and partially transliterated. Hyaluronic acid, for instance, is usually ヒアルロン酸 — transliterated first half, Japanese suffix.
Quasi-drug ingredient lists are structured differently
Regular cosmetics list ingredients in a single series, in descending order of weight, with a few exceptions permitted below one percent concentration. Quasi-drugs (医薬部外品) use a different structure: the approved active ingredient (有効成分) is listed separately, followed by the other ingredients (その他の成分) in a second section.
The practical implication for an overseas buyer: when you see a two-section ingredient list on a Japanese pack, you are looking at a quasi-drug, and the active ingredient listed first is the component that unlocks the product's medicinal claims under Japanese regulation.
Common ingredients and their Japanese names
A short reference of ingredients buyers commonly encounter:
- Water → 水 (mizu)
- Glycerin → グリセリン
- Butylene glycol → BG or ブチレングリコール
- Hyaluronic acid → ヒアルロン酸
- Sodium hyaluronate → ヒアルロン酸Na
- Niacinamide → ナイアシンアミド
- Ascorbic acid / vitamin C → アスコルビン酸
- Alpha arbutin (whitening quasi-drug active) → アルブチン
- Tranexamic acid (whitening quasi-drug active) → トラネキサム酸
- 4MSK (whitening quasi-drug active) → 4MSK
- Ceramide (often NP, NG, AP, EOP variants) → セラミド + suffix
Tools and resources
The Japan Cosmetic Industry Association (JCIA) publishes the definitive ingredient nomenclature reference, but it is in Japanese and not freely available. For practical translation work, three resources tend to cover most cases: the CosmeticsInfo JCIA registry, COSMILE's ingredient database (cosmile.jp), and @cosme's ingredient wiki. For regulated actives in quasi-drugs, MHLW publishes approved-ingredient lists that are the authoritative reference.
Our monthly reports include a glossary of any unusual Japanese-specific ingredient names encountered in the covered SKUs, with the corresponding INCI-standard names in English. For subscribers doing regulatory review in a destination market, this saves a translator round-trip.
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