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Ruhplush

Period & cramp relief

Yes, heat genuinely helps. Here’s how much, and how warm.

A randomised trial published in Obstetrics & Gynecology compared continuous low-level heat against ibuprofen for menstrual pain and found it performed comparably. A later meta-analysis pooling several trials agreed on the direction.

The number that matters is around 40 °C, held steadily — warm and sustained, not hot and brief. Thirty to sixty minutes, then a break. Hotter is not better, and above about 50 °C the safety margin collapses fast.

If that’s all you came for, that’s the whole answer, and the longer version is here. The rest of this page is about the object we’re building.

RuhPlush concept render — a plush strawberry with embroidered butterfly wings
Concept render — not final product photography.

The 2am problem

Everything warm has something wrong with it.

A hot water bottle
Genuinely good, and then a lukewarm sloshing thing in the bed you have to get up and deal with.
An electric pad
Works well, ties you to a socket, and looks like medical equipment on your bed.
A gift-aisle wheat bag
Weighs nothing, can't be washed, and after a year of reheating it smells faintly of toast.
Painkillers alone
Fine, and a different mechanism — which is why heat and NSAIDs are usually recommended together, not instead.

What we’re making

Warm, heavy, and flat on the back so it stays put.

About 1.5 kg of glass micro-beads in a sealed pouch. The whole thing goes in the microwave with the cover on, and the back is deliberately flattened so it lies across a stomach instead of rolling into the gap between you and the mattress.

No wheat, so it will never develop the smell. No socket. And it doesn’t look like it came from a pharmacy, which matters more than it should: an object you’re happy to leave visible is an object you actually reach for.

The full specification
1.5kg
Of glass micro-beads
30cm
Wingtip to wingtip
0g
Metal, anywhere in it
1part
Comes off for the wash

The waitlist

It doesn’t exist yet. Be there when it does.

No deposit, no pre-order, no countdown timer. An email address, and the first production run offered to you before anyone else.

One confirmation email, then roughly twice a week. Leave whenever you like — one click, no login.

Questions

About heat and cramps.

How long should I use heat for?
Thirty to sixty minutes, then a break. The trials use continuous low-level heat rather than a short blast — warm and sustained beats hot and brief. Reheating something partway through a session is fine and is what most people do anyway.
Can I use it with painkillers?
Yes, and it's common advice. NSAIDs work on prostaglandins directly, which is a different mechanism from heat, so the two aren't in competition. If you're unsure, ask a pharmacist — they're free and they know.
Is it better than a hot water bottle?
Different, and honestly not better on every axis. A hot water bottle is cheaper, available now, and holds a lot of heat because water holds a lot of heat. What this has instead is about 1.5 kg of gentle weight, a flattened back so it stays on your stomach rather than sliding off, nothing to refill at 2am, and a cover that goes in the wash. If what you want is maximum heat for minimum money, buy the bottle.
Will it help with endometriosis pain?
Heat may help you feel more comfortable. It does not treat endometriosis, and nothing on this site should delay you getting a diagnosis. Endometriosis takes an average of several years to identify, partly because people are told severe period pain is normal. It isn't.
Can I sleep with it?
There's nothing in it that can keep heating — no battery, no element, no socket. It comes out of the microwave at its hottest and cools from there, which is the failure mode that doesn't exist. What still applies to any warm object: heat it to warm rather than hot, and keep a layer of clothing between it and your skin.

Please see a doctor if pain regularly stops you doing normal things, if it’s getting worse, if painkillers at normal doses aren’t touching it, or if there’s heavy bleeding or pain outside your period. Cramps that dominate your life are not something to manage with a warm object and a shrug. Heat may help you feel more comfortable; it does not treat or diagnose whatever is causing the pain.

Sources

  1. 01Akin M. et al. — Continuous low-level topical heat in the treatment of dysmenorrhea (Obstetrics & Gynecology, 2001)Randomised trial; heat performed comparably to ibuprofen for menstrual pain.
  2. 02Jo J., Lee S. H. — Heat therapy for primary dysmenorrhea: systematic review and meta-analysis (Scientific Reports, 2018)
  3. 03NHS — Period painFor the thresholds on when to see a doctor.

More reading

We write about this properly.

Sourced, hedged where it should be hedged, and honest about where the evidence runs out. The journal has the long versions.

One confirmation email, then roughly twice a week. Leave whenever you like — one click, no login.