Are you woken at night with leg cramps? Do period cramps keep you in bed with a hot water bottle? Do sudden spasms leave you doubled over? While harmless, cramps can be intensely painful — and many people are told that magnesium is the “magic mineral” to fix them.
Below we cover whether magnesium helps, which types to consider, how much to take, the state of the research, and practical ways to use it.
What causes cramps?
Cramps happen when muscles contract suddenly and involuntarily. Triggers include certain medications (e.g., diuretics, some PPIs), metabolic disorders, hypertension, cardiac arrhythmia, dehydration, alcohol, pregnancy, stress, intense exercise, and magnesium deficiency.
Common signs of low magnesium include tight or aching muscles, twitches, and frequent cramps (often in the calves/feet).
Is magnesium good for cramps?
Because magnesium is crucial for nerve transmission and muscle contraction, correcting a deficiency can help. However, evidence for using magnesium to treat idiopathic cramps (with no clear cause) is mixed:
- Muscle/leg cramps: Several trials show little to no benefit on frequency; a minority report reduced severity.
- Period cramps (dysmenorrhea): Studies more consistently suggest magnesium may ease cramps, likely via muscle relaxation and lowering prostaglandins.
What type of magnesium is best for cramps?
There’s no single “best” type for everyone. Tolerability and goals matter:
- Magnesium L-threonate + citrate: High bioavailability; commonly combined in sleep/calm blends.
- Glycinate (bisglycinate): Gentle on the gut; popular for relaxation and sleep support.
- Citrate: Well absorbed; can have a mild laxative effect (often helpful if constipated).
- Taurate: Magnesium + taurine; a calming option, with emerging cardio-interest.
- Sulfate (Epsom salt): Used in baths for relaxation; evidence for transdermal absorption is limited, but many find the routine soothing.
- Oxide: Poorly absorbed; more likely to loosen stools — not ideal for repletion.
Read more: Magnesium L-threonate
How much magnesium should I take?
Start low and increase as needed and tolerated:
- Typical supplemental range: 200–400 mg elemental magnesium daily.
- Upper guidance: The NHS advises ≤400 mg/day from supplements; the WHO suggests a supplemental limit around ≤350 mg/day.
Always follow your product’s label and speak with your clinician, especially if you’re pregnant, have kidney disease, or take medicines that interact with magnesium.
Does research support magnesium for cramps?
Muscle & leg cramps
Evidence is inconclusive overall; some participants report subjective benefit, but pooled analyses generally show little effect on idiopathic cramps.
Period cramps
Small studies suggest magnesium may help reduce menstrual cramp severity — likely by relaxing uterine muscle and lowering prostaglandins.
Read more: Magnesium for PMS
How to use magnesium for cramps
Magnesium bath flakes (Epsom)
Add to a warm bath for relaxation. Evidence for significant magnesium absorption through skin is limited, but the ritual can help with wind-down.
Magnesium powder
Mix with water for quick dissolution and potentially better tolerability/bioavailability versus tablets.
Magnesium tablets/capsules
Take with food to reduce GI upset. Be consistent — daily use matters more than timing. Powders or well-chelated forms may be gentler.
How to buy the best magnesium for cramps
- Look for third-party lab testing (purity, potency, heavy metals).
- Choose clean formulas (Non-GMO, minimal additives).
- Check the label shows elemental magnesium per serving and the specific form (e.g., “magnesium glycinate”).
Frequently asked questions
Will magnesium stop my night leg cramps?
Not reliably for everyone. Some people improve, especially if they’re deficient, but studies on idiopathic leg cramps are mixed. It’s reasonable to try a well-tolerated form for 4–8 weeks.
Which magnesium is gentlest on the stomach?
Glycinate and L-threonate are typically easy on digestion. Oxide and high-dose citrate can be more laxative.
What helps period cramps most?
Magnesium can help some people with menstrual cramps. Many choose glycinate or a well-absorbed blend. Consistency matters (start before your period).
How long until I notice a difference?
For menstrual comfort, some notice changes within 2–3 cycles. For general cramp frequency, give it 4–8 weeks while addressing hydration, electrolytes, and training load.
Who should avoid or be cautious?
People with kidney disease, on interacting meds (e.g., some antibiotics, bisphosphonates), or with certain heart issues should seek medical advice first.
Final words
Magnesium is vital for muscle and nerve function, and correcting a deficiency may reduce cramps — especially menstrual cramps — though evidence for idiopathic leg cramps is mixed. Choose a well-absorbed form you tolerate, keep within daily limits, and pair with good hydration, electrolytes, and recovery. When in doubt, speak with your healthcare professional.
