Nutrition & supplements
Magnesium
Do you need a magnesium supplement — or just a handful of seeds?
Magnesium is essential and many people eat less than recommended. Food is the safest source. Supplements have an upper limit, interact with some common medicines, and are risky with reduced kidney function.
In 30 seconds
The short answer
Magnesium helps run muscles, nerves, blood sugar and blood pressure, and is used to build protein, bone and DNA.1 Many people eat less than recommended,18 yet a deficiency with symptoms is uncommon in otherwise healthy people because the kidneys hold on to it.20 Food is the safest source: magnesium in food does not need to be limited.8 Supplements are different — they have an upper limit,7 they interact with some medicines, and they can be dangerous when the kidneys are not working well.10
- Food first. Seeds, nuts, beans, whole grains and leafy greens are good sources.13
- Supplements have a limit. For adults it is 350 mg a day from supplements and medicines, not counting food.7
- Timing matters with some medicines, including certain antibiotics and osteoporosis medicines.2728
- Kidney disease is the hard stop. Reduced kidney function raises the risk of magnesium toxicity.10
Where magnesium goes in the body
Where magnesium goes
A simplified illustration based on the NIH Office of Dietary Supplements description.
You eat it
Seeds, nuts, beans, whole grains and greens bring magnesium in.13
The gut absorbs part
Typically about 30% to 40% of the magnesium in food.16
Bones and cells store it
Most is in bone and soft tissue; less than 1% is in the blood.3
Kidneys keep the balance
They hold on to it when intake is low and remove excess in urine.817
Where the body keeps its magnesium
What the research says
For high blood pressure, heart disease and diabetes, taking magnesium supplements is not currently advised.35
- Magnesium is a helper in more than 300 enzyme systems in the body.2
- 48% of Americans get less magnesium from food and drinks than their estimated average requirement.19 Men over 70 and teenagers are most likely to fall short.18
- In the short term, too little magnesium causes no obvious symptoms.22
- A blood magnesium test is the most common check, but it does not accurately reflect total body magnesium.4 No single test is considered satisfactory.5
- Magnesium supplements might lower blood pressure, but only by a small amount.32
- There is not enough evidence to recommend magnesium to improve blood sugar control in diabetes.33
- Small studies found a modest reduction in how often migraines happen — to be tried only under medical care.34
Food first: where the magnesium is
Most nutrients should come from food and drinks,39 and you can reach recommended amounts of magnesium by eating a variety of foods.13 These are some of the richest everyday sources, per ordinary serving.
Magnesium per serving, selected foods
Typical values for these foods, not a measurement of anyone's intake or of a ProperHealth or Clarkson product.
How much, and the upper limit
| Life stage | Recommended daily amount (all sources) | Upper limit (supplements and medicines only) |
|---|---|---|
| Men | 400–420 mg6 | 350 mg7 |
| Women | 310–320 mg6 | 350 mg7 |
| Pregnant women | 350–360 mg6 | 350 mg7 |
| Breastfeeding women | 310–320 mg6 | 350 mg7 |
| Teen boys 14–18 | 410 mg6 | 350 mg7 |
| Teen girls 14–18 | 360 mg6 | 350 mg7 |
| Children 9–13 | 240 mg6 | 350 mg7 |
The upper limit can look lower than the recommended amount. That is because it counts only supplements and medicines, while the recommended amount counts everything, including food.7
The clinic's approach
The Pakistan Institute of Medical Advancement in Karachi, whose documents inform this site, lists magnesium ascorbate once, in a handwritten formulary. No use, dose or rationale is written next to it.
The clinic's formulary, and the evidence
Magnesium appears once in the clinic's documents: a handwritten formulary entry.
Magnesium ascorbate, listed in the clinic's handwritten formulary
Listed in the clinic formularyNot assessed here- Where the clinic says this
- Handwritten formulary, page 1.41
- The clinic's stated rationale
- None written. It sits in a group whose heading appears to read "Asp / Plavix".41
- Evidence and limitations
- With no stated use, there is no clinic claim to assess. In general, magnesium supplements might lower blood pressure only slightly, and for heart disease they are not currently advised.3235 Kidney disease raises the risk of magnesium toxicity.10
- What this means for you
- Tell your doctor and pharmacist about every supplement you take, including magnesium.38
From the Dr. Majid Ali archive
A historical perspective
“I must confess I am very reverential to magnesium.”— Dr. Majid Ali, 2014-06-02Magnesium was one of Dr. Ali's most persistent subjects. He argued that deficiency was more common than testing suggested, because so little of the body's magnesium is in the blood.
On that point current sources agree more than you might expect: less than 1% of body magnesium is in the serum, and a serum test does not accurately reflect total body magnesium.34 The sources used here do not support what he built from it: intravenous protocols and treatment claims.
Where ProperHealth stops. The sources used here do not support his intravenous or "integrated" magnesium therapy, and magnesium is not presented here as a treatment for heart disease or any other condition. For those conditions, supplements are not currently advised.35 "Miracle", in one of his titles, is his word, not ours.
What to do next
Add one magnesium-rich food
Seeds, nuts, beans or leafy greens. A handful of pumpkin seeds is 156 mg.14
Read the form on your label
Citrate, aspartate, lactate and chloride are absorbed more easily.23 Oxide and carbonate are among the forms most often linked to diarrhea.24
Check the total against the limit
Add up supplements and magnesium-containing laxatives or antacids. The adult limit is 350 mg a day, not counting food.726
Space it from certain medicines
Some antibiotics and osteoporosis medicines need hours apart from magnesium.2728
Kidney disease? Ask first
Reduced kidney function raises the risk of magnesium toxicity. Talk to your clinician before starting.10
Medicines, supplements and safety
A pharmacist can check the form and amount on your label, total it across products and set timing around your other medicines. A pharmacist does not test your magnesium level, diagnose a deficiency or treat a condition with it.
- Antibiotics. Magnesium binds to tetracyclines such as doxycycline and quinolones such as ciprofloxacin. Take them at least 2 hours before or 4 to 6 hours after a magnesium supplement.28
- Osteoporosis medicines. Magnesium-rich products can reduce absorption of alendronate and similar medicines; keep them at least 2 hours apart.27
- Diuretics. Long-term loop or thiazide diuretics can increase magnesium loss; potassium-sparing diuretics such as spironolactone reduce it.29
- Acid reducers. Prescription PPIs taken for more than about a year can cause low blood magnesium.30
- Kidneys. The risk of magnesium toxicity rises when kidney function is reduced.10 Most cases of high blood magnesium happen in people with kidney failure.12
- Labels. "Supports" claims are not pre-approved by FDA,36 and FDA does not approve supplements for safety and effectiveness before sale.37
Compared
Conventional and integrative care, compared
Magnesium as a medicine and as a nutrient: what the test does and does not show, the real interactions and toxicity, who runs short, and which supplement claims hold.
What conventional treatment does
- Magnesium is a medicine as well as a nutrient: it is in some laxatives and some heartburn and indigestion products.26 A blood (serum) test is the most common check, but it does not accurately reflect the total magnesium in your body,4 and no single test is considered satisfactory.5 The upper limit is 350 mg a day for adults, counting supplements and medicines only, not food and drinks.7
Limits and adverse effects
- High intakes from supplements and medicines can cause diarrhea, nausea and stomach cramping; extremely high intakes can lead to an irregular heartbeat and cardiac arrest.9 The risk of toxicity rises with reduced kidney function or kidney failure.10 The forms most often reported to cause diarrhea are magnesium carbonate, chloride, gluconate and oxide.24
- Interactions: magnesium-rich products reduce absorption of osteoporosis medicines such as alendronate — separate them by at least 2 hours;27 magnesium binds tetracyclines such as doxycycline and quinolones such as ciprofloxacin, which go at least 2 hours before or 4 to 6 hours after;28 long-term loop or thiazide diuretics increase magnesium loss;29 long-term PPIs can cause low blood magnesium;30 very high zinc doses interfere with it.31
Who runs short, and why
- 48% of Americans get less magnesium from food and drinks than their estimated average requirement,19 yet in otherwise healthy people a deficiency with symptoms from low intake alone is uncommon, because the kidneys limit how much is lost.20 More likely to get too little: people with Crohn's or celiac disease, type 2 diabetes, long-term alcohol use disorder, and older people.21 Refining grains in ways that remove the germ and bran substantially lowers their magnesium.15
Integrative and naturopathic approaches, by evidence
Evidence levels: EstablishedEmergingHypothesisNot supported
- Established
Food first: legumes, nuts, seeds, whole grains, green leafy vegetables such as spinach, fortified cereals, and milk and yogurt;13 an ounce of roasted pumpkin seeds gives 156 mg, half a cup of boiled spinach 78 mg, half a cup of brown rice 42 mg against white rice's 10 mg.14 Magnesium in food and drinks is not harmful and does not need to be limited.8
- Emerging
Magnesium supplements might lower blood pressure, but only by a small amount.32 Several small studies found supplements can modestly reduce how often migraines happen — only under the care of a health care provider.34
- Not supported
The American Diabetes Association finds not enough evidence to recommend magnesium to improve blood sugar control,33 and taking supplements for high blood pressure, heart disease or diabetes is not currently advised.35 "Supports" wording on labels is not pre-approved by the FDA.36 The clinic's formulary lists magnesium ascorbate in a group headed "Asp / Plavix" with no use or dose written.41
If you have kidney disease, ask a doctor before any magnesium supplement, laxative or antacid;46 and tell every provider about every supplement and medicine you take.38
When to get help now
Each warning sign cites the official guidance behind it. The wording still needs pharmacist sign-off.
- Fainting, chest pain, or an irregular heartbeat with dizziness or shortness of breath — call 911.4243
- Extreme muscle weakness, confusion or slow, difficult breathing after taking magnesium products — call 911.4445
- If you have kidney disease, ask a doctor before using a magnesium supplement, laxative or antacid — side effects from high magnesium are more likely with significantly reduced kidney function.4647525354
- Diarrhea with blood or a fever — contact your provider right away. Diarrhea that is not better after 5 days, even after stopping the supplement — contact your provider.4849
- Numbness, tingling or cramps that are new, spreading or worsening — book an appointment rather than self-treating.5051