Which magnesium is right for you?

What does magnesium do?

Magnesium is involved in hundreds of processes in the body — muscle contraction and relaxation, nerve signalling, energy production, and maintaining a steady heart rhythm. It also contributes to normal bone structure and helps regulate blood pressure.

Because it's needed in so many places, low intake can show up in different ways: cramping, poor sleep, tension, or low energy. Most South African diets provide some magnesium through leafy greens, nuts, seeds and whole grains, but modern diets, stress and certain medications can all reduce how much the body actually retains.

Signs you may be low in magnesium

• Muscle cramps or twitches, especially in the calves at night
• Trouble winding down or restless sleep
• Tension headaches
• Fatigue that doesn't match your activity level
• Constipation or irregular digestion

These signs are common and have many possible causes, so they're not proof of a magnesium shortfall on their own. If they persist, a blood test can help confirm whether magnesium is part of the picture.

Magnesium forms compared

If you only want one form, start with your main goal: glycinate for evening calm, a complex for all-round support, or oxide if regularity is the main concern.

Magnesium for sleep

Magnesium contributes to normal muscle relaxation and nervous system function, which is why many people take it in the evening. Glycinate (bisglycinate) is the form most often chosen for this because it's gentle on the stomach and less likely to cause the laxative effect some other forms have. A consistent bedtime routine and reduced screen time before bed still matter more than any single supplement.

Magnesium for muscle cramps

Low magnesium is one of several factors linked to muscle cramps, particularly at night. Magnesium contributes to normal muscle function, so a consistent daily intake may help if low levels are part of the cause. Dehydration, prolonged standing or sitting, and intense exercise are other common triggers worth ruling out first. For more on this, see our guide to magnesium and night leg cramps.

Magnesium for constipation

Magnesium oxide and magnesium citrate both draw water into the bowel, which is why they're commonly used for occasional constipation. Oxide is more concentrated and has a stronger effect; citrate is milder and better absorbed. Start with the lower end of the suggested dose and drink enough water alongside it.

Medications that can lower magnesium

Certain medications can reduce magnesium levels over time, including long-term proton-pump inhibitors (reflux medication), some diuretics, and certain antibiotics. If you take any of these regularly and notice cramping, fatigue or poor sleep, it's worth asking your doctor or pharmacist whether your magnesium should be checked. See our full guide on medications that can lower magnesium.

How much magnesium per day?

Recommended daily intakes for adults are generally in the region of 300–420 mg, depending on age and sex, though needs can vary. Follow the dose on your NutriZen product label rather than combining multiple magnesium products at once, since elemental magnesium can add up quickly across formulas. If you have kidney disease, speak to your doctor before supplementing, since the kidneys clear excess magnesium.