Value Village ／ Beauty
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Gel nails (jeru neiru) are hugely popular in Japan: they last 3–4 weeks and the colour stays bright. But a steady number of people report "my nails got thinner" or "I got a rash". This article looks at how the nail is built and how to give your nails a rest if you want to keep having gel done.
| Item | Guide |
|---|---|
| How fast fingernails grow | About 0.1 mm a day, about 3 mm a month. Full replacement from root to tip takes about 6 months |
| Thickness of a healthy nail | About 0.3–0.5 mm. If over-filing makes it thinner, it bends and can hurt |
| Interval between re-applications | 3–4 weeks. Left longer, water gets in through the gap at the base |
| How to remove | Soak in acetone (the ingredient in nail-polish remover) for 10–15 minutes, then lift off gently. Forcing it off peels away layers of the nail plate (the hard surface of the nail) |
| Lamp | UV or LED lamp. Curing time is 30–60 seconds depending on the product. Some people protect the back of the hand with sunscreen or gloves |
| Rest period | After 3–4 months of gel, a break of 2–4 weeks is a realistic approach |
[Verify] The figures for nail growth rate, thickness and curing time are general guides. Check the year of publication and the number of cases in the National Consumer Affairs Center's gel-nail harm information and reflect them in the article.
The main causes of thinning are over-filing and forced removal. Gel itself does not dissolve the nail. It helps to choose a salon that uses a "non-sanding" base gel or a technician who files as little as possible.
The surface of the nail plate comes off with it. Repeated, this visibly thins the nail. Remove with acetone, or at the salon.
Nails do not breathe (they are fed by the blood supply at the nail root). The point of a rest is to give the filed part time to grow out and to give you a chance to notice any problem with the skin or nail.
Acrylate ingredients are common to most gels, so once an allergy has appeared, people often react to other makers' products too. Have a dermatologist identify the ingredient responsible first.
That seals in the bacteria and makes it worse. For green nails, the first step is to take the gel off and keep the nail dry. Then see a dermatologist for medical care.
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https://www.kokusen.go.jp/
https://www.dermatol.or.jp/uploads/uploads/files/guideline/contact_dermatitis_GL2020.pdf
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.
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.
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