Live Well Vitamins & Lifestyle Guide
Magnesium
Magnesium is a mineral that’s crucial to the body’s function. Magnesium helps keep blood pressure normal, bones strong, and the heart rhythm steady.
Magnesium Uses
Experts say that many people in the U.S. aren’t eating enough foods with magnesium. This mild magnesium deficiency could put them at risk for a number of diseases.
For instance, there’s good evidence that eating foods high in magnesium and other minerals can lower blood pressure. Magnesium supplements may help some people with heart disease and osteoporosis. Type 2 diabetes is also associated with low magnesium.
Intravenous or injected magnesium is used to treat other conditions, such as eclampsia during pregnancy and severe asthma attacks. Magnesium is also the main ingredient in many antacids and laxatives. Ask your doctor about other uses of magnesium.
Severe magnesium deficiencies are rare. They’re more likely in people who
- Have kidney disease
- Have Crohn’s disease or other conditions that affect digestion
- Have parathyroid problems
- Take antibiotics or drugs for diabetes and cancer
- Are older adults
- Abuse alcohol
Doctors sometimes suggest that people with these conditions take magnesium supplements.
Magnesium Dose & Instructions for Use
The recommended dietary allowance (RDA) includes the magnesium you get from both the food you eat and any supplements you take.
|
Category |
Recommended Dietary Allowance (RDA) |
|
CHILDREN |
|
|
1-3 years |
80 mg/day |
|
4-8 years |
130 mg/day |
|
9-13 years |
240 mg/day |
|
FEMALES |
|
|
14-18 years |
360 mg/day |
|
19-30 years |
310 mg/day |
|
31 years and over |
320 mg/day |
|
Pregnant |
Under 19 years: 400 mg/day |
|
Breastfeeding |
Under 19 years: 360 mg/day |
|
MALES |
|
|
14-18 years |
410 mg/day |
|
19-30 years |
400 mg/day |
|
31 years and up |
420 mg/day |
It’s safe to get high levels of magnesium from food. But excessive use of magnesium supplements can be toxic. The upper limit -- the highest dose a person can take -- of magnesium supplements is
- 65 mg/day for children ages 1-3
- 110 mg/day for children ages 4-8
- 350 mg/day for adults and children ages 9 and up.
Magnesium Food Sources
Natural food sources of magnesium include:
- Green, leafy vegetables, like spinach
- Nuts
- Beans, peas, and soybeans
- Whole-grain cereals
Whole foods are always best. Magnesium can be lost during refinement and processing.
Magnesium Supplement Information
Magnesium comes in many forms. Magnesium is in multivitamins, antacids, and laxatives. Doctors also give magnesium intravenously or by injection. Like any supplement, keep magnesium in a cool, dry place, away from humidity and direct sunlight.
Magnesium Warnings
- Side effects. Magnesium supplements can cause nausea, cramps, and diarrhea.
- Interactions. Magnesium supplements may not be safe for people who take diuretics, heart medicines, or antibiotics.
- Risks. People with diabetes or intestinal disease shouldn’t take magnesium without checking with a doctor.
- Overdose. Signs of a magnesium overdose include nausea, diarrhea, low blood pressure, muscle weakness, and fatigue. At very high doses, it can be fatal.
WebMD Medical Reference

GNC Live Well | ![]() |


WebMD Live Well Health Check
Which vitamins and supplements may help you meet your goals?
Take It Now!Vitamins & Supplements Glossary
- Amino Acids. The building blocks that make up proteins…
- Botanicals. Substances obtained from plants and used in food supplements…
- Fat-Soluble. Vitamins that are stored in the liver and body fat…
- Micronutrients. Vitamins and minerals that your body needs in small amounts…
- Phytochemicals. Healthful compounds found in fruits, vegetables, and other plants…
- View All Terms




