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Description
Kao Megrhythm Steam Warming Sheet — Direct-to-Skin Type, 16 Sheets, Japanese General Medical Device
Overview
Kao's 蒸気の温熱シート releases gentle moist steam at about 40 °C for five to eight hours. It sticks straight onto the skin — this is the direct-to-skin type, not the over-clothing type — and it is thin enough not to show under a shirt. In Japan it is registered as a 一般医療機器, a general medical device.
Kao lists four areas: the neck, the shoulders, the back and lower back, and the abdomen, where the maker states the warmth supports gastrointestinal function. Our previous listing omitted the abdominal use entirely, which left a third of the product's purpose off the page.
Read the cautions before the first sheet. Skin held at 40 °C for hours can burn without ever feeling hot — this is what 低温やけど, a low-temperature burn, means, and it is the reason this product has a warning block rather than a warning line. Our previous page carried one sentence of it. See the rest of our Japanese body care.
This product is registered in Japan as a general medical device (一般医療機器) — the lowest-risk regulatory class for devices, which is where self-adhesive warming sheets sit. It is a device rather than a cosmetic or a medicine, and the cautions further down this page are the manufacturer's, not ours.
Key Benefits
- ✓ Moist steam heat at about 40 °C, sustained for 5–8 hours — steam warmth rather than dry heat, and it does not wet clothing
- ✓ Sticks directly to skin — thin, flexible and discreet under a shirt or blouse
- ✓ Four intended areas: neck, shoulders, back and lower back, and the abdomen, where Kao states it supports gastrointestinal function
- ✓ Fragrance-free (無香料) — usable at a desk or on a commute without anyone noticing
- ✓ Registered in Japan as a general medical device (一般医療機器), which is the class self-adhesive warming sheets sit in
- ✓ 16 sheets per box — an authentic Kao product, shipped from Japan
- ✓ Full manufacturer cautions on this page, including the low-temperature burn risk our previous listing did not state
Product Details
| Brand | Megrhythm (めぐりズム), by Kao Corporation |
|---|---|
| Product name (JP) | 蒸気の温熱シート 肌に直接貼るタイプ |
| Regulatory class | 一般医療機器 — general medical device (Japan) |
| Product type | Self-adhesive steam-generating warming sheet |
| Quantity | 16 sheets |
| Warmth | Approx. 40 °C, sustained 5–8 hours |
| Scent | Fragrance-free |
| Intended areas | Neck, shoulders, back and lower back, abdomen |
| Country of origin | Japan |
| JAN code | 4901301236883 |
Who Is This For?
- People with stiff shoulders or a stiff neck from desk work — the classic Japanese 肩こり, and the reason this product exists
- People with lower-back tension who want warmth they can wear under clothes through a working day
- People who feel the cold and want a discreet source of warmth on a commute or in an over-air-conditioned office
- People who want warmth on the abdomen, which Kao lists as an intended area
- Not for: anyone who cannot remove the sheet themselves, anyone whose sensation of heat is impaired, infants, anyone who cannot say they are uncomfortable, or use while asleep — all of these are how a low-temperature burn happens
How to Use
- Open the individual pouch only when you are ready to use the sheet — the warming reaction starts on contact with air.
- Peel off the film and apply the sheet directly onto clean, dry skin over the area you want to warm: neck, shoulders, back, lower back or abdomen.
- Place it over soft tissue, not over a bone the sheet would press against, and do not lie or press on it while wearing it.
- Warmth builds within a few minutes and holds at about 40 °C for five to eight hours. Remove it at the end of that, or sooner if it feels too warm.
- Check the skin under it from time to time. If it reddens, itches or stings, take it off at once — a low-temperature burn can form without sharp pain.
Frequency: One sheet per area, up to 5–8 hours. Never while sleeping.
Full Ingredients
This is a device rather than a formulated product, so there is no ingredient declaration in the cosmetic sense. The sheet works by an iron-oxidation warming reaction: the pouch is airtight, air reaches the contents when you open it, and the reaction generates warmth and moist steam. The typical contents of a Japanese warming sheet of this kind are iron powder, activated carbon, water, a water-retaining material such as vermiculite, and salt.
It is fragrance-free, and nothing is absorbed into the skin — the sheet warms, it does not medicate. Anyone with an adhesive sensitivity should note that it does have a skin adhesive, and should patch-test a small area first.
Cautions
- Risk of low-temperature burn (低温やけど). Skin held at about 40 °C for hours can burn without ever feeling hot. This is the main hazard of the product and the reason for every line below
- Do not use while sleeping. You cannot monitor the skin or remove the sheet while asleep
- Do not use on anyone who cannot remove it themselves, or whose sensation of heat is impaired — this is the group a warming sheet actually injures
- Not for infants, or for anyone who cannot communicate that they are uncomfortable
- Do not combine with another heat source, and do not press or lie on the sheet while wearing it
- Do not apply over broken skin, a rash, sunburn, or immediately after a bath
- Apply over soft tissue, not over a bone the sheet would press against
- Remove immediately if the skin reddens, itches or stings, or if the heat feels too strong — do not wait for pain
- If a burn is suspected, cool the area and seek medical advice
- Keep out of reach of children
Package Contents
16 sheets, each sealed in its own airtight pouch, inside the printed Kao carton with the Japanese instructions. The individual pouches are what keep the unused sheets inert — the warming reaction only starts when a pouch is opened.
Shipping & Store Notes
- Ships directly from Japan
- Processing time: 2–6 business days
- Tracking number provided after dispatch
- Import duties and taxes may apply depending on destination country
- Opened cosmetics cannot be returned for hygiene and safety reasons
Authenticity Guarantee
Every product at Tsujimoto Market is sourced directly from Japan and verified for authenticity. We never sell fakes or grey-market goods. Each order is carefully packed in Kobe, Japan and dispatched with full tracking.
FAQ
What is a low-temperature burn, and why does this product warn about it?
It is a burn caused by prolonged contact with a moderately warm surface rather than a brief contact with a hot one. At about 40 °C, hours of contact can damage skin while it never feels hot enough to react to — so the warning sign most people rely on, pain, does not arrive in time. That is why the cautions here say to check the skin periodically and remove at the first redness, and why the sheet must never be worn while asleep.
Is this the type that goes on skin or over clothing?
Directly on skin. Kao makes both; this is 肌に直接貼るタイプ, the direct-to-skin type. Do not use it over clothing, and do not use the over-clothing type directly on skin — the adhesive and the heat profile are designed differently.
Can I use it on my stomach?
Yes. Kao lists the abdomen among the intended areas and states that warming there supports gastrointestinal function. Our previous listing left this out entirely, which is one of the reasons the page was rewritten.
Will it show under my clothes or make them damp?
It is thin and flexible enough not to show under a shirt, and Kao states that the steam does not wet clothing. It is also fragrance-free, which is what makes it practical at a desk or on a commute.
Is it a medicine?
No. It is registered in Japan as a 一般医療機器 — a general medical device, the lowest-risk device class. It warms; it does not deliver any active substance into the skin.
