If you’re looking to try magnesium for its many well-being benefits, you might be wondering: how much magnesium should I take? In this article, we’ll cover how much magnesium you need for good health and how you can make sure your supplement is meeting your magnesium needs. First, here’s a quick reminder of why magnesium is so important in the first place…
What does magnesium do?
Magnesium is one of the essential minerals that your body needs to maintain optimal health. It’s also part of a smaller group of minerals called electrolytes, responsible for maintaining your body’s “electrical circuit”. Altogether, magnesium is involved in over 300 processes in the body, including some rather important ones:
- Muscle and nerve function
- Bone synthesis (creation)
- Blood sugar control
- Blood pressure regulation
- Heart rhythm
- Immune regulation
- Energy production
- DNA and RNA synthesis
- Protein synthesis
When you don’t get enough magnesium, all of these functions can suffer. That’s why magnesium deficiency is associated with serious conditions like cardiovascular disease, high blood pressure, type 2 diabetes, osteoporosis, ADHD, and even Alzheimer’s disease. But when we say “enough” magnesium, how much are we talking about?
How much magnesium do I need?
For adults, the Nation Institutes of Health recommends that men aim up to a maximum of 420mg of magnesium per day and women aim for 320mg (slightly more if pregnant or nursing). Ideally, you should be able to get all the magnesium you need from a varied diet, including foods like:
Ideally, you should be able to get all the magnesium you need from a varied diet, including foods like:
- Leafy green vegetables like spinach and kale
- Seeds and nuts, especially almonds, cashews, and peanuts
- Lentils, beans, and chickpeas
- Whole grains, quinoa, and buckwheat
- Brown rice
- Fatty fish like salmon and mackerel
- Dark chocolate
(You can find out more about dietary sources of magnesium in our in-depth article Magnesium-Rich Foods.)
Of course, not everybody is able to get enough magnesium in their diet. Others do, but they might have other factors that mean they need more magnesium than the average person (more on that later!).
So how much magnesium should I take per day?
The recommended magnesium dosage and intake change depending on your age and sex. The table below shows the adequate intake (AI) and recommended dietary allowance (RDA) from the National Institute of Health.
|Birth to 6 months||30 mg*||30 mg*|
|7–12 months||75 mg*||75 mg*|
|1–3 years||80 mg||80 mg|
|4–8 years||130 mg||130 mg|
|9–13 years||240 mg||240 mg|
|14–18 years||410 mg||360 mg|
|19–30 years||400 mg||310 mg|
|31–50 years||420 mg||320 mg|
|51+ years||420 mg||320 mg|
*Adequate Intake (AI)
These are just broad guidelines, but let’s take a look at some more common factors that might affect how much magnesium you should take…
a. How much magnesium do you get in your diet?
Diet is the most common reason for magnesium deficiency. Official estimates are that up to 50% of the US population is not getting enough magnesium in their diet. In other parts of the world, the UK Food Standards Agency’s annual National Diet and Nutrition Survey found that a “substantial proportion” (i.e. the majority) of adults are not getting enough magnesium in their diets. There’s also the issue of a drop in food quality, which means foods that should have lots of magnesium often don’t.
If you suspect that you don’t get enough in your diet, or you can’t eat more magnesium-rich foods, then it’s a good idea to take the maximum dose of a quality magnesium supplement to treat or avoid a deficiency.
When you’re looking to take a higher dose of magnesium, it’s important to choose a magnesium type with:
- Good tolerance, so that you can take higher doses without uncomfortable side effects (more on those later!).
- High bioavailability, so that your body will absorb more of the magnesium and you’ll get more of the benefits.
b. What are you taking it for?
Aside from deficiency, you may want to take a magnesium supplement for some of its other well-being benefits, like sleep or mood support. Here’s what the research says about recommended dosage for some of the more common usages.
- Sleep. A dose of 500mg has been shown to improve sleep onset and quality. Learn more about magnesium for sleep.
- Diabetes. Doses as low as 250mg have been shown to have a positive effect on blood sugar and insulin resistance. However, the best results seem to happen from 300mg to 360mg per day onwards. The higher the dose, the better the results, with the highest dose reducing diabetes risk by 22%.
- Cardiovascular health. Doses from 300mg to 360mg of magnesium have been shown to have a positive effect on cholesterol. Learn more about magnesium for heart health.
- Blood pressure. Magnesium has been shown to reduce blood pressure in some people with as little as 240mg per day. However, results are better and more consistent from 300mg upwards, with some people needing around 370mg to 400mg to see results.
- Bone health. One review looked at studies using 250-1800mg of magnesium and found that in all cases, there was definite improvement in bone density and reduced fracture risk.
- Pregnancy. We already know pregnancy is a time of increased magnesium need. Around 360mg of magnesium a day has also been shown to improve circulation to the baby, and may decrease the risk of a dangerous condition called pre-eclampsia.
- Reproductive health. A rather low dose of 200mg a day has been shown to improve water retention from PMS. Upping your dose to 360mg might also help with PMS-related mood difficulties.
- Migraines. Studies on using magnesium for migraines often use higher doses, with 500mg and 600mg doses shown to significantly reduce the frequency and severity of migraines. Learn more about magnesium for migraines.
- Mood. Magnesium has provided relief from depression symptoms at doses as low as 248mg, but doses of around 450mg or more provide more consistent results.
- Muscle pain. For muscle cramps, including those caused by pregnancy, doses of 300mg upwards have been shown to be effective. The positive effects seem to increase with higher doses, though, with a young boy experiencing complete recovery from chronic muscle pain with doses of 520mg. Learn more about magnesium for cramps.
- Exercise performance. Research indicates that doses under 250mg of magnesium a day are not effective in improving exercise performance. 350mg seems to be the ideal minimum, shown to improve athletic performance in a group of volleyball players.
c. Do you have any health conditions?
Certain health conditions mean that you might need more magnesium than the average person to maintain healthy levels or experience the benefits you want. Here are some examples:
- Stress depletes magnesium levels and reduces absorption.
- Gastrointestinal disorders like Crohn’s, celiac disease, and ulcerative colitis all interfere with magnesium absorption.
- Kidney problems or type 2 diabetes cause greater magnesium loss by increasing urination.
- Alcoholism affects magnesium levels in different ways, e.g. vomiting prevents absorption, and kidney disease increases loss.
- Pregnancy diverts magnesium to your growing baby, so you need more to make sure your own needs are met, too.
To recap, regardless of the benefits you’re looking for, research suggests that the dosage of your magnesium supplement should be at least 300mg a day, with benefits generally increasing with the dosage. And if you have certain health conditions, then you might need more. However, in this case, it’s absolutely essential to discuss your magnesium dose with your doctor or another healthcare professional first.
There are two reasons for this. First, some health conditions can actually make your body less efficient at getting rid of excess magnesium, so you could end up with dangerously high magnesium levels from supplements. Second, magnesium supplements can affect the metabolism of some common medications you might be taking, so you may end up with too much or too little medication in your system. Your doctor can advise you and make sure that you’re taking the right amount of magnesium for your specific needs.
What if I take too much magnesium?
In a healthy person, it’s actually very difficult to overdose on magnesium. It would take incredibly high doses to reach poisonous levels, and your body is great at filtering out what it doesn’t need.
You might recall that we said the general upper dosage is around 400mg. However, this is just the point at which some people (but not all) start to experience mild side effects, like nausea or bloating. The higher you go over this upper limit, the more likely those side effects are, but you’re still very unlikely to overdose.
Digestive side effects are more common with magnesium citrate and oxide, and less common with better-tolerated forms like taurate, glycinate, and malate. If you’d like your dose to be on the higher side, then, it’s best to go with one of these types. If you do find yourself experiencing side effects, simply lower your dose until you find a level that’s comfortable for you.
How much magnesium does my supplement contain?
Your supplement label should tell you how much magnesium a dose contains. Be sure to read the label carefully as the total daily dose of magnesium might be spread across multiple servings, e.g. two capsules once a day, or one capsule three times a day.
The magnesium will be part of a compound, e.g. magnesium malate (magnesium and malic acid), but you’re looking for just the magnesium content. This is sometimes referred to as elemental magnesium.
On the label, you might see something like:
“320mg of magnesium from 1600mg of magnesium malate.”
“320mg elemental magnesium from magnesium malate.”
“1600mg of magnesium malate with 320mg magnesium.”
In each case, your supplement would contain 320mg of elemental magnesium. So even though you’d be taking 1600mg of magnesium malate, you’d still be under the recommended daily limit of 375-400mg of magnesium.