What do people get wrong about Japanese toner (keshōsui)?
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Japanese toner (化粧水, keshōsui) is talked about as the symbol of Japanese skincare, and there is a bottle in almost every bathroom here. Its role is widely misunderstood. One term from dermatology changes the way you see it.
An index called "transepidermal water loss"
Quite apart from sweat, a small amount of water is constantly evaporating from the skin through the stratum corneum (the outermost layer). This is called transepidermal water loss (TEWL), and the lower the value, the stronger the barrier function of the stratum corneum. Comparing TEWL before and after use is one method used in cosmetic evaluation tests.
Moisturising agents fall into two broad groups.
| Group | Typical example | How it works |
|---|---|---|
| Water-based | Glycerin etc. | High affinity with water molecules; holds water in the skin |
| Oil-based | Petroleum jelly (Vaseline) etc. | Forms an oil film on the skin surface and physically blocks evaporation |
Toner is mainly the former. Its role is to "give"; the role of "not letting go" belongs to the oils in milky lotion (乳液, nyūeki) and cream.
[Verify] The explanation of TEWL is based on the glossary of the Society of Cosmetic Chemists of Japan (SCCJ) and a pharmaceutical company's material for healthcare professionals. Check before publication.
Misunderstanding 1｜The more you use, the better
Using more does not change how much evaporates. What matters is not the number of applications but the step that follows.
Misunderstanding 2｜It is the same thing as "lotion" in English
Japanese keshōsui is sometimes labelled "lotion" in English, but it is not the milky, creamy product that word usually suggests to English speakers. It is a watery liquid.
Misunderstanding 3｜The moist feeling right after applying is the effect
The feeling right after is the stratum corneum temporarily holding water. Feel is not the same as result. The effects that a product may claim as a cosmetic are limited to 56 items by a Ministry of Health, Labour and Welfare notice (Japan regulates cosmetic claims under the Pharmaceuticals and Medical Devices Act, its cosmetics and drugs law).
Misunderstanding 4｜Using a cotton pad is the correct way
Hands or a cotton pad: the basic rule is to follow the product's directions. Not rubbing is described as more important.
Misunderstanding 5｜Skipping it is not an option
Depending on your skin and the products you combine, reducing the number of steps is also a choice. More steps does not mean more correct.
---
Sources
- Society of Cosmetic Chemists of Japan (SCCJ), cosmetics glossary, "Transepidermal water loss" [経表皮水分蒸散量]
https://www.sccj-ifscc.com/library/glossary_detail/487
- Ministry of Health, Labour and Welfare, notice of the Director-General of the Pharmaceutical and Food Safety Bureau, "Revision of the scope of cosmetic efficacy claims" [化粧品の効能の範囲の改正について] (Yakushoku-hatsu 0721 No. 1, 21 July 2011)
https://www.mhlw.go.jp/file/06-Seisakujouhou-11120000-Iyakushokuhinkyoku/kesyouhin_hanni_20111.pdf
- Japanese Dermatological Association (公益社団法人 日本皮膚科学会), "Dermatology Q&A" [皮膚科Q&A]
https://www.dermatol.or.jp/qa/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
About this article
What we share here are ideas and everyday practices passed down among people living in Japan, together with general information drawn from public sources. They are not official recommendations, and they are not professional instruction. Practices vary between households and regions.
This is general information. Results vary from person to person and depend on your own conditions and surroundings.
Please decide for yourself, using your own judgement, whether any of this suits your situation. We cannot accept responsibility for any damage, loss or injury arising from following this article.
Cosmetics are not medicines and are not meant to diagnose, heal or prevent any condition. If your skin reacts, stop using the product and see a dermatologist.
Sources
Tell us if this has changed
Approved contributions keep the contributor's name, shown in five languages.
Related questions
Other languages：日本語 ／ 简体中文 ／ 繁體中文 ／ 한국어
Value Village is not a government body. Always confirm procedures on the official site.
Written by Value Village from public sources. Nothing here is reproduced from another site.