# Hot water bottles and heat therapy

> The cosy classic, backed by research

Category: Movement & sleep · 2 min read · Written by the Splash team · Sources checked October 2026
URL: https://splash.care/learn/movement-sleep/heat-therapy

## Quick answer

- The NHS recommends heat for period pain.
- Reviews suggest heat can ease pain, and may work about as well as some painkillers.
- Wrap it, never use boiling water, and replace old bottles.

Good news: your hot water bottle is not just a comfort blanket. The NHS recommends a heat pad or hot water bottle wrapped in a tea towel for [period pain](https://splash.care/learn/period-care/cramp-relief), and research backs it up.

A 2018 review found that in three small trials, heating [pads](https://splash.care/learn/period-care/products-compared) relieved period pain better than painkillers. A much bigger 2025 review of 57 trials (5,359 people) found heat probably reduces pain compared with doing nothing, and may work about as well as anti-inflammatory painkillers, with fewer side effects. Heat is not a cure for everything, but it is cheap, cosy and low-risk when used safely.

## Ways to use heat

- A hot water bottle wrapped in a tea towel on your tummy or lower back
- An electric heat pad on a low setting
- Stick-on heat patches under clothes
- A warm bath or shower

> Stay safe: never use boiling water in a hot water bottle, do not overfill it, always wrap it, check it for wear and replace old ones, and do not fall asleep on an electric heat pad. Take extra care if you have reduced feeling in your skin, as you may not notice a burn.

> **Splash says:** heat plus gentle movement plus a cuppa is the holy trinity of cramp care.

**Myth:** Heat makes your period heavier.

**Fact:** We found no good evidence that a hot water bottle or warm bath makes you bleed more. It may just help you feel better.

### When to see a doctor

See a GP if cramps are severe, stop you going to school or work, do not improve with heat and painkillers, or are getting worse over time. Ask for an urgent appointment or call NHS 111 if pain is severe or worse than usual and painkillers have not helped.

## Sources

1. [NHS: Period pain](https://www.nhs.uk/symptoms/period-pain/)
2. [Jo & Lee (2018) Heat therapy for primary dysmenorrhea: systematic review and meta-analysis, Scientific Reports](https://pmc.ncbi.nlm.nih.gov/articles/PMC6214933/)
3. [Yuan et al. (2025) Heat therapy for primary dysmenorrhea: systematic review and meta-analysis of 57 trials, Frontiers in Medicine](https://pmc.ncbi.nlm.nih.gov/articles/PMC12876241/)
4. [ACOG: Dysmenorrhea: Painful Periods](https://www.acog.org/womens-health/faqs/dysmenorrhea-painful-periods)

This is general information, not medical advice. Splash can’t diagnose. If you’re worried, talk to a GP, pharmacist or sexual health clinic. In an emergency call 999 (UK) or 911 (US).