Menstrual cramps (period pain): what helps?

What are menstrual cramps?

Menstrual cramps are lower abdominal pain tied to a period, and in the first few years of menstruating they are part of the usual pattern. ACOG describes typical early cycles as running 21–45 days, with bleeding for 2–7 days and cramps on the first day or two that ease with ibuprofen or a hot water bottle. Some mood changes or bloating beforehand are also common.

Sometimes the pain has another cause. The NHS lists endometriosis, adenomyosis, fibroids and pelvic inflammatory disease, and notes that an IUD can cause pain in the first 3–6 months after fitting. Our guide to endometriosis covers that condition in full. For pain outside the usual pattern, the person to ask is your doctor or OB-GYN in the US, or your GP in the UK.

What does the evidence show helps?

The evidence shows that anti-inflammatory painkillers, heat and exercise can each ease cramps, and the painkillers have been tested in by far the most trials. These drugs are called NSAIDs, a group that includes ibuprofen and naproxen.

A 2015 Cochrane review by Marjoribanks and colleagues gathered 80 randomized controlled trials involving 5,820 women. The relief figures at the top of this page come from 35 of those trials, where NSAIDs were set against placebo, a dummy treatment with no active drug.

The same review counted side effects. They were reported by 10% of women on placebo and 11–14% of those on NSAIDs, mostly gastrointestinal (stomach and gut) or neurological. In plain terms, NSAIDs caused slightly more side effects than a dummy pill.

Heat has suggestive support. A 2018 systematic review and meta-analysis by Jo and Lee in Scientific Reports found 6 randomized trials: 2 favored heat over an unheated placebo, 3 found heating pads more effective than painkillers, and 1 found a benefit over no treatment.

A 2019 review of self-care by Armour and colleagues pooled 23 trials with 2,302 women. Exercise, heat and acupressure all reduced period pain. Exercise had the largest effect, and both exercise and heat did better than analgesics (painkillers) for pain intensity.

How much, and how are these options used?

For ibuprofen or naproxen, the pattern is to take it with food on the days cramps arrive, usually the first day or two of a period. Dose and spacing are set out on the package: the Drug Facts label in the US, the patient information leaflet in the UK. If you take other medicines, a pharmacist is a good person to ask before you start.

ACOG's guidance names ibuprofen, with naproxen as the other NSAID used for cramps. In the UK, the NHS names paracetamol (acetaminophen in the US) or ibuprofen as the first painkillers to try.

For heat, the usual tools are a heating pad, a heat patch or a hot water bottle held against the lower abdomen. The NHS words it as a hot water bottle or heat pad wrapped in a dish towel (a tea towel in the UK), and adds warm baths or showers.

Magnesium is the least certain option on this page. The range given for the reproductive years is 200–300 mg a day, with a weak-to-moderate rating: it may ease period cramps and PMS for some women. In perimenopause the range is 200–400 mg a day, and the glycinate form is described as gentler on the stomach. Many women treat it as an optional extra after painkillers, heat and movement.

How strong is the evidence?

The evidence points in a consistent direction, yet every review on this page flags limits. The Cochrane authors rate the side-effect findings for NSAIDs as low quality, the heat review's authors call for better trials, and confidence in the self-care review is limited by risk of bias, meaning the way the trials were run could have tilted the results.

That makes the figures best read as a direction, not a precise measure. A percentage from pooled trials describes groups of women, so it cannot say how any one person will respond, and the reviews do not set out which option will suit a particular woman.

For supplements, a Cochrane review of 27 randomized trials with 3,101 women found no high-quality evidence for any dietary supplement, with every comparison rated low or very low quality. That review covered fish oil, melatonin, vitamins B1 and E and zinc sulfate, not magnesium, so it neither supports nor counts against the magnesium range given earlier.

Next steps

A good place to start is one or two options from this page, such as an anti-inflammatory painkiller with food and some heat, given a few cycles to show whether they help. If the pain is getting worse or stops you training, a visit to your doctor or OB-GYN (your GP in the UK) is a sensible next step. Some women prefer home options, others lean toward medication or hormonal birth control, and many combine them. It is not one size fits all, so you decide what fits you.