Magnesium Supplements

Bioavailable MagnesiumMagnesium is required for over 300 enzymatic reactions throughout the body, and is the king of energy, mood and muscle. No wonder this essential mineral is one of the most popular supplements on the markets, but did you know that taking the wrong form of supplemental magnesium can cause more harm than good?

NOTE: We recommend speaking to a qualified nutritionist or naturopath for personalized advice on the safest and most effective options before taking a new magnesium supplement.

What is a “form” of magnesium?

Magnesium ions are difficult for the intestines to absorb and must be bound to a carrier if we have any hope of absorbing them into the body.

For example, magnesium citrate is a magnesium ion attached to a citric acid molecule; magnesium oxide is magnesium ion attached to an oxygen (oxide) molecule, and so on.

Ultimately, the magnesium bonded to the carrier is the same as any other – it is the carrier that determines how the magnesium survives digestion, its rate of absorption, and how it acts in the body. In some cases, the carrier also exerts its own therapeutic effects.

Here’s a quick guide to the most common forms of magnesium supplements, how they’re different and what they’re good for:

Best Magnesium Forms6 Most Popular Types of Magnesium Used in Supplements (some are terrible!)

1. Magnesium Oxide

Bioavailability: Very low

Magnesium oxide (MgO) is a magnesium molecule bound to oxygen. This means that it’s possible to pack a lot of elemental magnesium into this kind of supplement – in fact, it has the most magnesium of any form of supplement. But here’s the catch – the oxygen portion (oxide) renders this form of magnesium quite difficult to absorb. In fact, only about 4% will be taken up by the intestines [1]. The remaining will move through the digestive tract, altering the electrolyte balance of the bowel, and pulling in water – often resulting in diarrhea.

To put it frankly, the only time to take a large dose of magnesium oxide, also known as “magnesia”, is when you are in need of a serious laxative. It may also help to relieve acid reflux and other stomach disorders as it acts as an antacid, but check with a qualified nutritionist or naturopath first – and remember that it comes with a side effect of spending a lot of time on the toilet and potentially abdominal cramping.

Even though this is a pharmaceutical type of magnesium with very specific uses, it is often found in cheap magnesium supplements as somewhat of a “filler”. Always check the ingredients of supplements before you buy them.

NOTE: Other forms of magnesium with laxative effects include magnesium carbonate and magnesium sulfate when taken orally.

GREAT FOR: Laxative effects, though there are gentler options out there!

AVOID IF: You are looking to boost your magnesium levels quickly and effectively.

We recommend – Healthcare Mag-Ox (400mg, 120 capsules)

Magnesium Oxide SupplementMag-Ox is a household name when it comes to pharmaceutical grade magnesium oxide. Each capsule delivers 400mg which is more than a standard therapeutic dose, so we recommend that you start with one and build up from there if necessary. We also recommend speaking to a nutritionist or naturopath before taking magnesium oxide.

2. Magnesium Citrate

Bioavailability: Good

Magnesium citrate is a molecule of citric acid attached to a magnesium ion, and is one of the most common forms of magnesium supplements on the market. It’s cheap to make and has fairly good absorption rates, especially compared to magnesium oxide [2].

The issue with magnesium citrate is that the citrate portion is quite large, meaning that only a small amount of magnesium can fit into the molecule as a whole. Per weight, you will find less magnesium in a magnesium-citrate powder than a magnesium-oxide powder. But bioavailability isn’t all about how much magnesium is packed into the supplement – magnesium citrate is very absorbable and considered one of the best bioavailable magnesium supplements for the price.

Citric acid itself is used in the Krebs cycle (aka the citric acid cycle) and for maintaining bone health – both of these processes also require magnesium as a cofactor [3].


  • Bone health
  • Energy
  • Magnesium citrate is one of the cheapest ways to easily boost your magnesium levels.
  • Taken in high amounts, it can also act as a laxative. This is a positive or a negative, depending on your personal health!

AVOID IF: You have a sensitive stomach or are suffering from diarrhea.

We Recommend – Pure Encapsulations Magnesium Citrate (150mg, 180 capsules)

Magnesium Citrate SupplementThis magnesium citrate supplement is hypoallergenic and free from additives. Pure Encapsulations pride themselves on producing clean, pure supplements with no gluten, egg, soy, peanuts, artificial colours, coatings or sweeteners, and this magnesium citrate is no exception – it contains only magnesium citrate with ascorbyl palmitate as an antioxidant and natural preservative, packaged in a vegetarian cellulose capsules. Two capsules a day is considered a therapeutic dose, but you can go as high as four per day in divided doses.

3. Magnesium Orotate

Bioavailability: Excellent

Magnesium orotate is a type of “chelate” where a magnesium ion bound to orotic acid (aka “orotate”). Orotic acid is naturally manufactured in the body to fuel energy production, particularly within heart cells. Orotate also has a nifty effect of providing extra cellular binding sites for magnesium to latch onto – as sort of a “magnesium-fixing agent” [4].

Magnesium orotate is highly stable in the digestive system and blood stream, reducing loss of magnesium from digestion and degradation. It’s poorly soluble in water, but that’s good news – this means that the compound won’t bind to gastric acid or cause any laxative effects. Its absorption into the body is excellent, but don’t believe the hype that orotic acid carries magnesium across the membrane of cells – there’s no evidence suggesting this is true. The myth may stem from its ability to promote additional binding sites on certain cells.


  • Cardiovascular health. Orotic acid and magnesium both improve heart health and may reduce blood pressure [5].
  • Gut health. Magnesium orotate is particularly gentle on the bowel and is a great option if you have found other magnesium forms to have a laxative effect.


  • You suffer from any uric acid disorders. Orotic acid can lead to an increase in toxic ammonia.
  • You have megaloblastic anemia. High levels of orotic acid can exacerbate the condition of overgrown red blood cells.

We Recommend – Bulk Supplements Pure Magnesium Orotate Powder (250mg)

Magnesium Orotate SupplementBulk Supplements offer a powdered magnesium orotate with no added fillers, colors or flavors at a reasonable price. This is a highly concentrated powder that is easily dissolved – – mix with water, juice or add to smoothies to hide the slight metallic taste. Just ¼ teaspoon twice a day will deliver a therapeutic dose.

4. Magnesium Glycinate

Bioavailability: Excellent

Glycine is an amino acid that is responsible for creating nucleic acids, regulating nerve signals, promoting digestive health and more. Magnesium can be combined with one glycine molecule (magnesium glycinate) or more — magnesium diglycinate refers to two glycinate molecules and bisglycinate refers to three.

When bound to glycine, magnesium becomes highly absorbable and bioavailable – there’s virtually no risk of laxative effects with this form of magnesium. The dipeptide bond between glycine and magnesium is particularly strong and the combination is readily absorbed in the intestines. Because of this strong bond and quick absorption, magnesium ions aren’t left floating freely through the intestines where they can draw water into the stomach and intestinal tract, causing nausea, bloating and diarrhoea.

The downside of a glycinate complex is that there isn’t much room for magnesium – you won’t find as high a dose of elemental magnesium per capsule in these kinds of supplements as with magnesium citrate or magnesium orotate. However, the absorption is much better – glycine can even boost the absorption of magnesium by gently decreasing the pH in the intestines.


  • Digestive health – Magnesium can help to relax and regulate bowel movements, while glycine supports the production of bile and can balance the acid-base ratio in the stomach to reduce symptoms of reflux or heartburn.
  • Sleep health – Magnesium is a cofactor in the production and function of hormones and chemicals required for sleep. As a nervous system relaxant, it can help to prime the body for deeper sleep and prevent conditions like restless leg syndrome. Glycine plays a role here too – it acts as a neurotransmitter on its own, or can be used in the production of GABA, an inhibitory, relaxing neurotransmitter required for sleep onset and maintenance [6].

AVOID IF: You have a gallbladder disease. Speak to a qualified nutritionist to assess whether glycine may help or exacerbate your particular condition.

We Recommend – Thorne Research Magnesium Bisglycinate Powder (237g)

Magnesium Bisglycinate SupplementThorne Research offer a simple magnesium bisglycinate powder in a high concentration. This is an exceptionally clean product – the only other ingredients are monk powder and citric acid for natural sweetness and flavor. Powders are the most absorbable form of magnesium, and just one scoop twice daily is enough to meet a therapeutic dose.

View Thorne Magnesium Bisglycinate on Amazon

5. Magnesium Aspartate

A magnesium deficiency can cause a symptomatic state described as feeling “wired and tired” – like you’re bugging out of brain with stress but have no energy to back it up. Magnesium aspartate is particularly effective at treating this symptom picture.

Aspartate – not to be confused with the neurotoxin, aspartame – is also known as “aspartic acid”. It’s an amino acid and a major excitatory neurotransmitter [7] which means that is promotes activity in the brain and nervous system and can give you the sensation of feeling more awake, focused, and energized.

It may seem strange to combine magnesium with such a stimulatory acid – isn’t magnesium for relaxation? Don’t forget that magnesium is an essential cofactor in the Krebs cycle to create ATP, and in the excitatory actions of muscle contraction, neuron-firing, and vitamin D metabolizing. Magnesium aspartate has been shown to be particularly effective for promoting exercise endurance [8] and relieving depression symptoms [9].

Magnesium aspartate is a dipeptide with the same issues as magnesium glycinate – a low amount of elemental magnesium can “fit” in the molecule but its absorption is incredibly high, resulting in excellent bioavailability.


  • Energy
  • Pre-workout
  • Endurance
  • Exercise recovery
  • Relieving fatigue
  • Improving concentration
  • Lifting mood


  • You suffer from insomnia or sleep problems – if you need to take magnesium aspartate for daytime energy, consume it at least 6 hours before bedtime.

Speak to a qualified nutritionist if you have a neuro-chemical imbalance of any kind before taking magnesium aspartate.

We recommend – Bulk Supplements Magnesium D-Aspartate (250g)

Magnesium D-Aspartate SupplementBulk Supplements provide one of the cleanest, easier and most absorbable magnesium aspartate supplements on the market. Free from sugar, dairy, soy, yeast, gluten and additives (yes – all additives!), and it’s cheap. Just ½ teaspoon of powder per day gives a therapeutic dosage. Easy.

6. Magnesium Chloride or Sulfate

Bioavailability: Good to Excellent

If your digestion is sluggish or nutrient absorption is compromised, you can still get magnesium into your system – magnesium chloride and magnesium sulfate can bypass the pitfalls of oral consumption by being applied topically and absorbed straight through the skin. Kind of sci-fi, huh?

Soaking in an epsom salt bath or foot-bath can boost your magnesium levels – the salts are made of magnesium sulfate which penetrates the skin and delivers magnesium right into the blood stream and directly to muscle cells.

New to the market is magnesium oil – this is a liquid form of magnesium chloride in higher concentrations than what you’d find in an epsom salts bath, applied directly to the skin and quickly absorbed..


  • Immediate and on-going relief of muscle tension, pain and stiffness.
  • Boosting magnesium levels when digestion is compromised.
  • Easy application before bed to promote restful sleep.

AVIOD IF: You have a sensitive skin condition.

We recommend – Ancient Minerals Magnesium Oil (8 oz.)

Magnesium OilsAncient Minerals source their magnesium chloride and associated trace minerals from the salts of the Ancient Zechstein sea, an unadulterated and protected geological form that stretches from Northern Poland to the eastern coast of England – a rich and pure source of magnesium chloride.

There is 100mg of elemental magnesium in every 6 sprays (1mL) of this easy-to-use magnesium oil, which is enough to reach a low therapeutic level – remember, topical magnesium bypasses the losses that occur with oral supplementation.

Other Forms of Magnesium Supplements

There are seemingly endless ways that scientists can combine magnesium with different acids for other therapeutic effects on the body. There is a lot of mixed research out there on forms like magnesium taurate, magnesium malate, magnesium glutamate, magnesium threonine and more – speak to a qualified nutritionist for personalized advice.

Further Reading:

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  1. Agnes Soderbeck says

    Thank you for the helpful reviews. But on several, #4 Sundown, #3 Now Foods and #2 Nature Made you don’t mention the type of magnesium these are. That seems to be rather important information don’t you think? When the type of magnesium isn’t mentioned, it usually ends up being magnesium oxide… the cheapest, most common, most bio-unavailable, most digestively troublesome form. Is that true here?

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