Magnesium: What it does, how to get enough, and when to supplement

Think of magnesium as a quiet helper your body needs for energy, nerves, muscles and bones. It’s involved in hundreds of chemical reactions, and not getting enough can show up as muscle cramps, low energy, trouble sleeping or an irregular heartbeat. The good news: you can fix most mild shortfalls with food or a smart supplement choice.

Foods rich in magnesium are easy to add to your day. Eat spinach, pumpkin seeds, almonds, black beans, whole grains and dark chocolate. A cup of cooked spinach or a small handful of pumpkin seeds can move your intake up quickly. If you rely heavily on processed food, you’re more likely to fall short.

Which magnesium is right for you?

Not all magnesium supplements act the same. Here’s a short, practical guide:

Magnesium glycinate — gentle on the stomach and good for sleep or anxiety. Citrate — better absorbed and can ease constipation. Oxide — cheap but less absorbed and can cause loose stools. Chloride or topical Epsom baths (magnesium sulfate) — useful for skin or sore muscles, though absorption varies. Choose based on your goal: sleep, digestion, or general repletion.

Dosing matters. The recommended daily amounts vary by age and sex, but adult men usually need around 400–420 mg and adult women 310–320 mg from food and supplements combined. Many experts suggest keeping supplemental elemental magnesium under 350 mg per day to avoid diarrhea, unless supervised by a clinician.

Safety, interactions, and quick tips

If you have kidney problems, talk to your doctor before taking magnesium supplements—your kidneys clear excess magnesium, and impaired function raises risk. Magnesium can also interfere with certain drugs: take antibiotics like tetracyclines or fluoroquinolones, bisphosphonates, levothyroxine and some heart medicines several hours apart from magnesium.

How do you know if you’re deficient? Blood tests aren’t perfect because most magnesium sits inside cells. Look at symptoms (leg cramps, persistent fatigue, sleep trouble) and dietary habits. If you suspect low magnesium, try increasing high-mag foods for a few weeks and see if you improve—or ask your healthcare provider about checking levels or trying a short supplement trial.

Practical tips: take magnesium with a meal to reduce stomach upset; try glycinate at night if you want help with sleep; use citrate if constipation is an issue. Start with a low dose and increase slowly. If you get diarrhea, cut back.

Magnesium isn’t a miracle cure, but it helps a lot of people feel better when intake is low. If you’re on medications, pregnant, or have kidney disease, check with your clinician first. Otherwise, focus on food, pick the right supplement for your goal, and use sensible doses.