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Magnesium and Magnesium Supplements

Heather Bray, RD

Have you been wondering if you should be taking a magnesium supplement?

There’s been a lot of talk about magnesium supplements lately and for good reason. Most people aren’t meeting their daily magnesium needs through food. There are a number of different statistics out there on magnesium deficiency, one of which has suggested that 1 in 3 Canadians are not getting enough magnesium [1]. Some people are also at higher risk of magnesium deficiency for example those taking prescription medications for heartburn/reflux/GERD called proton pump inhibitors (PPIs).

*Disclaimer: the views and opinions of this article are based on the best available evidence and my professional opinion as a Registered Dietitian. This article is not meant to act as or substitute for medical or medical nutrition advice. For medical or medical nutrition advice that is designed for your individual needs, please consult your doctor or Registered Dietitian.

Before diving into the supplements I want to let you know that you should be striving to meet your magnesium needs through food because,

#1 You almost always absorb nutrients better when you get them from food instead of a supplement
#2 Any food that is high in a vitamin or mineral is likely high in several other beneficial macro or micronutrients

What is Magnesium and What Does It Do?

Magnesium is involved in 300-600 different chemical processes in the body [2]. It is a micronutrient that falls under the category of electrolytes (along with sodium, potassium, calcium, chloride, phosphate and bicarbonate). An electrolyte is an element that carries a “charge” which is needed to make some bodily functions happen [3]. Think of it as the electricity to make a light bulb go on.

Some of the bodily functions that magnesium plays a role in are:

  • Muscle contraction

  • Blood vessel contraction

  • Fluid balance inside and outside cells (aka hydration)

  • Neurological function and neurotransmitter release

  • Converting Vitamin D into an active form form (aka bone health) and helps the liver and kidneys process Vitamin D

  • Energy creation (i.e. helping to extract energy from food)

  • Blood sugar control

  • DNA and RNA creation and repair

Some of the popular claims and benefits of magnesium include:

  • Helping pregnant people with restless leg syndrome and/or muscle cramps

  • Decreasing PMS symptoms and severity (e.g. cramps, bloating)

  • Improving muscle recovery from workouts

  • Aiding in sleep latency (time it takes to fall asleep)

  • May help with migraines

  • Helps prevent and alleviate constipation

Magnesium Deficiency

When it comes to magnesium, deficiency can cause symptoms such as muscle weakness, restless leg syndrome or cramping. In severe cases, magnesium deficiency can cause heart arrhythmias (it’s important to note that too much magnesium can also impact heart function and in severe cases can cause cardiac arrest). However, most people with magnesium deficiency experience no symptoms or the symptoms are too vague to attribute to a magnesium deficiency. This compounded with the fact that it’s really difficult to test for magnesium deficiency makes this process even more confusing.

Magnesium deficiency has also been linked with chronic conditions such as diabetes and hypertension (high blood pressure) and other simple day-to-day physical ailments such as muscle cramps. Magnesium deficiency can often be accompanied by deficiency in other nutrients such as vitamin D, calcium and potassium.

How is magnesium deficiency measured?

One of the only and most common tests we have to check magnesium levels is a blood test (aka serum magnesium). Unfortunately, serum magnesium is not a good predictor of dietary intake (how much magnesium you get from food) or a diagnostic of deficiency. This is because, as explained above, magnesium is an electrolyte which means that blood levels of magnesium are constantly changing. Additionally, most of the magnesium in the body is present in bones and soft tissues and only 1% is present in serum levels [2].

A dietitian can help you evaluate if you are getting enough dietary magnesium (i.e. magnesium from food) and can help you figure out if you need supplementation based on your diet, lifestyle, medical conditions or medications.

Speaking of conditions, magnesium deficiency can be caused by conditions such as: poorly managed diabetes, kidney disease, malabsorptive gastrointestinal conditions (e.g. Crohn's, ulcerative colitis, short bowel disease or celiac disease) and alcoholism.

As mentioned above, magnesium deficiency can also be caused by some medications such as [4]:

  • Proton pump inhibitors (PPIs, e.g. omeprazole, pantoprazole),

  • Some high blood pressure medications called diuretics (thiazide diuretics called HCT and loop diuretics (furosemide), and

  • EGFR inhibitors

  • Some immunosuppressants

  • Insulin

  • Some antibiotics

  • COPD medication (called beta adrenergic agonists)

  • Some osteoporosis medication (called Bisphosphonates)

  • Some types of chemotherapy

It is hard to exactly pinpoint how much these medications decrease magnesium absorption and is highly individualized. Therefore it’s important to work with your doctor and/or dietitian to get the amount of magnesium you need.

How Much Magnesium Do I Need?

Here is the amount of magnesium individuals need each day [2].

Females (19+) 320 mg

Males (19+) 420 mg

Teens 360-410mg

Pregnant or Breastfeeding 310-400mg

Upper Limit

The upper limit of magnesium from supplements is 350 mg for both males and females. For those who take more than this, the most common side effect is diarrhea but muscle cramps can also be present.

As mentioned above, high magnesium supplementation can be harmful, especially if you have any cardiovascular conditions and/or are on prescription medications, be sure to check in with your doctor or pharmacist prior to taking magnesium supplements.

Magnesium In Food

We find magnesium in so many food sources (e.g. nuts, seeds, legumes, dark leafy greens). Unfortunately, most people do not consume enough of these foods which mean that they do not get enough dietary magnesium. As always, the goal is to try to meet your needs through food, therefore, try to add more of these foods into your diet.

Top foods for Magnesium

Pumpkin seeds (¼ cup), 317 mg

Chia seeds (2 Tbsp), 111 mg

Nuts (mixed, ¼ cup), 78-98 mg

Black-eyed peas (¾ cup), 121 mg

Black beans (¾ cup), 89 mg

Spinach, cooked (½ cup), 83 mg

Swiss Chard, cooked (½ cup), 80 mg

Soy milk (1 cup), 61 mg

Quinoa (½ cup), 60 mg

Peanut butter (2 tbsp), 49 mg

Potato, with skin (1 medium), 43 mg

Oatmeal (1 instant packet), 36 mg

Sources: [2], [10]

Other good sources of magnesium include:

  • Salmon, mackerel,

  • Soy beans, lima beans, pinto beans

  • Whole grains such as bread and breakfast cereals

Magnesium Supplement Breakdown

Magnesium Citrate

Well absorbed and tolerated. Helpful for: Constipation/digestion, provides a “relaxation effect” because of its quick absorption mechanism and ability to act on muscle tissues.

Magnesium Glycinate/Bisglycinate

Well absorbed Good for sleep, anxiety, stress, headaches and cramps

Magnesium Chloride

Well absorbed and tolerated, it’s used to help treat magnesium deficiency and may help with heartburn and constipation. It is also found in creams to help relieve muscle pain/cramps.

Magnesium L-Threonate

Good for brain health, easy on GI. Most effective form at increasing brain levels of magnesium. Early research suggests that this form may play a role in depression and memory loss. *should not be used to treat magnesium deficiency

Magnesium Malate

Good for pain, muscle fatigue, energy production and “calm”

Magnesium Oxide or Hydroxide

Not well absorbed, can cause GI distress but interestingly has been historically used to treat acute discomfort such as migraines, heartburn or indigestion. *this form is not commonly recommended

Magnesium Taurate

May help reduce blood pressure and improve blood sugar control, however, this has not been proven, more research is needed.

Sources [9], [11], [12]

Top RD Recommended Magnesium Supplement Forms: Magnesium citrate and magnesium glycinate.

Do I need a magnesium supplement?


For those who take medications that may lower their magnesium status or decrease magnesium absorption or with conditions mentioned above, the answer is almost always yes. It is important to check with your doctor or pharmacist prior to starting a magnesium supplement because other medications can negatively interact with magnesium supplements.

Additionally, both endurance athletes and those who participate in a lot of strength training may benefit from a magnesium supplement as electrolyte stores are often decreased from exercise (especially prolonged and strenuous exercise). Magnesium supplementation may also aid in the muscle recovery process and there is some evidence that it may help with delayed onset muscle soreness (DOMs). For example, a 2022 small randomized control trial found that college athletes (both male and female) who supplemented with 350mg magnesium for 10 days had less perceived muscle soreness after completing bench-press (repetitions to failure) and lower ratings of perceived exertion. Now this is just one small study, but there are many more that have shown similar outcomes. It is also worth noting that there have been several papers published on magnesium supplementation having little to no effect on muscle recovery. However, due to the low-risk nature of magnesium supplementation (for most people, as always check with your doctor or pharmacist first), it may be helpful to trial a magnesium supplement to see if this helps you with muscle recovery.

If you are not on any prescription medications, you are most likely safe to take a low-dose magnesium supplement anywhere from 150-300 mg per day [2],[11]. Do not exceed 350 mg per day.

The Bottom Line

While magnesium deficiency is very common, it can be corrected by aiming to eat more magnesium rich foods and potentially taking a low dose magnesium supplement. The food-first approach is always the way to go because all the foods listed above are also very nutrient dense foods which will add a significant overall nutrient boost to one’s diet.

Do you have questions about magnesium? Comment below or fill out our contact form!

Are you looking for help with meeting your nutrient needs or just with nutrition and general? Book a call with us today!

Until Next Time!

*Disclaimer: the views and opinions of this article are based on the best available evidence and my professional opinion as a Registered Dietitian. This article is not meant to act as or substitute for medical or medical nutrition advice. For medical or medical nutrition advice that is designed for your individual needs, please consult your doctor or Registered Dietitian.


2. National Institutes of Health, Magnesium Fact Sheet for Health Professionals, 2022

3. Isha Shrimanker; Sandeep Bhattarai. Electrolytes. 2022

4. Liamis G, Hoorn EJ, Florentin M, Milionis H. An overview of diagnosis and management of drug-induced hypomagnesemia. Pharmacol Res Perspect. 2021 Aug;9(4):e00829. doi: 10.1002/prp2.829. PMID: 34278747; PMCID: PMC8287009.

5., Serum Magnesium. 2017

7. Gröber U. Magnesium and Drugs. Int J Mol Sci. 2019 Apr 28;20(9):2094. doi: 10.3390/ijms20092094. PMID: 31035385; PMCID: PMC6539869.

8. Reno AM, Green M, Killen LG, O'Neal EK, Pritchett K, Hanson Z. Effects of Magnesium Supplementation on Muscle Soreness and Performance. J Strength Cond Res. 2022 Aug 1;36(8):2198-2203. doi: 10.1519/JSC.0000000000003827. Epub 2020 Oct 1. PMID: 33009349.

9. Consumer Lab. Magnesium Supplement Review. 2023

10. Alberta Health Services. Magnesium and Your Diet. 2019

11. Mike Murray, Magnesium. 2022

12. Adrienne Seitz, MS, RD, LDN Healthline. Magnesium Supplements: All You Need to Know. 2023

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