What are the common misunderstandings about using pain-relief patches (shippu)?
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Medicated patches (湿布, shippu) are Japan's most familiar painkiller. Every household keeps some, and visitors ask "why do Japanese people use so many patches?" Here we cover the difference between cooling and warming types, how the active ingredients are classified, photosensitivity, and the misunderstanding about "where they work".
Types and how to choose
| Item | Detail |
|---|---|
| Cooling vs warming | A difference in sensation (menthol = cooling; capsaicin or nonivamide = warming). Skin temperature barely changes. The usual split is cooling for acute pain (right after a knock or sprain), warming for chronic stiffness (a matter of preference) |
| Anti-inflammatory painkillers (first generation) | Methyl salicylate, glycol salicylate: mild pain. Mostly Class 3 OTC medicines (Japan's lowest-risk over-the-counter category) |
| Anti-inflammatory painkillers (second generation) | Diclofenac, loxoprofen, felbinac, indometacin, ketoprofen: stronger. Class 2 OTC medicines. Daily limit on the number of patches (e.g. loxoprofen: once a day, up to 2 patches) |
| Photosensitivity | Ketoprofen (and some felbinac products etc.) can cause a rash or dermatitis if the patched area is exposed to sunlight (take care for about 4 weeks after removal too). Follow the label and cover the area outdoors |
| How long to wear | Per the product label (8–12 hours, or once a day). Leaving a patch on too long causes dermatitis |
| Who and where not to use | Late pregnancy (NSAID-containing products), a history of asthma, skin with wounds or eczema, under 15 (some products) — check the label |
| Where it works | Absorbed through the skin at the patched site and acts locally. Does not work on internal or whole-body pain |
- Patches are medicines (Class 2 or Class 3 OTC) with dosage, directions and warnings on the label. They suppress pain and inflammation; they do not remove the cause of back pain.
- The Ministry of Health, Labour and Welfare (MHLW) and the PMDA (Pharmaceuticals and Medical Devices Agency) have repeatedly warned about photosensitivity from ketoprofen; the package insert says "do not expose the patched area to sunlight while wearing it and for 4 weeks after removal."
- Dermatitis (contact dermatitis) is the most common problem with patches. Do not patch the same spot day after day, wash the skin after removal, stop if redness appears.
- Also watch for children swallowing patches or sticking them on by mistake and older people using too many (over the limit).
[Verify] Check the classification of each ingredient, the daily patch limits and the photosensitivity warning against the product package inserts (PMDA).
Misunderstanding 1｜Cooling cools, warming warms
A difference in sensation; the temperature is nearly the same. The painkilling ingredient does the work. Cooling for acute, warming for chronic is a matter of preference.
Misunderstanding 2｜It's external, so any number is safe
Second-generation ingredients have a daily limit; many patches at once can cause the same side effects as tablets (stomach, kidneys). Stick to the number on the label.
Misunderstanding 3｜It's fine to be in the sun with a patch on
Ketoprofen and others cause photosensitivity. Cover the area with clothing; take care for about 4 weeks after removal too.
Misunderstanding 4｜The longer you wear it, the better it works
Beyond the labelled time (8–12 hours) you get dermatitis. Take it off and let the skin rest.
Misunderstanding 5｜Patches get rid of the cause of back pain
They suppress pain and inflammation; the cause stays the same. Combine them with movement, posture and warmth (see our article on back stiffness), and see a doctor for red-flag symptoms.
---
Sources
- Pharmaceuticals and Medical Devices Agency (PMDA), *Package insert information for OTC medicines (topical anti-inflammatory analgesics)* [一般用医薬品 添付文書情報（外用鎮痛消炎薬）]
https://www.pmda.go.jp/
- Ministry of Health, Labour and Welfare, *On photosensitivity caused by topical ketoprofen* [ケトプロフェン外用剤による光線過敏症について]
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/iyakuhin/
- Japan Self-Medication Industry (the OTC medicines association) [日本OTC医薬品協会], *How to use topical anti-inflammatory analgesics (patches) correctly* [外用鎮痛消炎薬（湿布）の正しい使い方]
https://www.jsmi.jp/
⚠️ 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.
This article is not meant to diagnose or manage any specific medical condition. If you are worried about your health, see a doctor rather than relying on your own judgement.
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