Types of Magnesium

Magnesium is an essential mineral required for over 300 enzymatic reactions in the body, including processes involving healthy muscle contraction, cardiovascular function, and DNA synthesis.

Elemental magnesium is not stable or bioavailable on its own, so it must be bound to a carrier to enter the bloodstream. Common carriers include a salt (citrate, oxide, or chloride) or a chelate with an amino acid such as glycine or taurine. The carrier determines both solubility and how well the ion survives digestion. Organic and water-soluble forms (such as citrate or glycinate) are generally more bioavailable than inorganic forms such as magnesium oxide. However, highly soluble salts such as magnesium chloride and sulfate dissociate quickly in the gut and draw water into the gut lining, resulting in a laxative rather than absorptive effect.

Chelated forms (such as magnesium glycinate) are bound to the magnesium, which facilitates absorption into the bloodstream.

Magnesium (Mg) bound to citric acid. One of the most-studied forms, widely available in supplements. Shown to have good bioavailability and generally used as an everyday supplement to support magnesium levels. Mg citrate has an osmotic effect in the digestive system (draws water into the bowel), which means it can be used in high doses to relieve constipation. A 2022 study found that Mg citrate improved arterial stiffness, possibly because citrate binds calcium, inhibiting calcium crystals and vascular calcification.¹

Forms: Capsules, tablets, powders. Supplements may provide around 200-450 mg/day.²

Contraindications: High dosages can cause gastrointestinal upset, including diarrhea, bloating, and gas. May not be suitable for those with renal conditions. 

Magnesium chelated to the amino acid glycine, an amino acid that acts as a neurotransmitter, supporting calm and potentially reducing pain hypersensitivity.³
Mg glycinate is promoted for relaxation and nervous system support. Some research has shown it may improve sleeplessness and sleep quality.⁴ It is gentler on the digestive system than other forms, which makes it preferable for long-term use.

Form/dose: Capsules, tablets, powders. Reported as beneficial at 250 mg elemental magnesium/day.

Contraindications: Generally well-tolerated.

An inorganic magnesium salt. Mg oxide has the highest elemental magnesium content by weight (around 60%) but very little is absorbed in the body.   

Widely used to relieve constipation due to its osmotic properties (draws water into the bowel) which increases stool volume and stimulates bowel motility.⁵ 

Often the cheapest form of magnesium, but its lower bioavailability limits its effectiveness.

Form: Capsules, tablets, powder. Dosages may range from 250-400 mg per day, depending on the product used and individual needs.

Contraindications: May cause gastrointestinal upset along with diarrhea, bloating and abdominal pain. May reduce absorption of some medications, including antibiotics, so these should be taken at least two hours away.

An inorganic salt comprising two chlorine atoms bound to a magnesium atom. Highly water-soluble; breaks down rapidly into free magnesium ions, so often used in transdermal products such as oils, sprays, and lotions. However, some research suggests that magnesium’s ionized form cannot penetrate a lipophilic layer.⁶
Good bioavailability in oral products. Used to support magnesium levels, often added to electrolyte products for rehydration.⁷

Forms: Tablets, liquids, powders, topical formulas (spray/oil).

Contraindications: Can cause gastrointestinal upset at high doses. Topical oils may cause skin irritation.

Magnesium bound to malic acid, an intermediate in the Krebs cycle (also known as the citric acid cycle) that facilitates cellular energy production. 

Mg malate has lipophilic properties which allow passive diffusion across intestinal membranes.⁸ A 2025 study found that Mg malate significantly increases magnesium levels in skeletal muscle and whole-brain tissue, thereby enhancing neuromuscular performance.⁹ It also induces BDNF elevation in the prefrontal cortex, which supports its role in enhancing executive function and stress resilience.¹⁰

Form: Capsules, tablets.

Contraindications: Standard GI effects in high doses. 

Magnesium bound to threonic acid (a natural byproduct of vitamin C). Threonic acid utilizes the brain's glucose transport channels to allow the magnesium to cross the blood-brain barrier, which other forms are unable to do. Mg threonate is shown to increase brain levels of magnesium more effectively than other forms, improving various aspects of cognitive function. A 2026 study found that supplementation over 6 weeks improved overall cognitive skills, including executive function, memory, attention, and processing speed. These results suggested enhanced synaptic plasticity and a reduction in brain cognitive age.¹¹​ A 2024 study also found that Mg threonate improved sleep quality, mood, energy, alertness, and daily productivity.¹²

Forms: Capsules, tablets, powders. Dosage may range from 1.5-2 g/day. Lower dose is sufficient due to enhanced bioavailability. 

Contraindications: Well tolerated.

An inorganic salt, commonly known as Epsom salts. Often added to bathwater to support muscle relaxation, although evidence is limited. Intravenous (IV) Mg sulfate may be used to restore severe magnesium deficiency, treat constipation, or prevent preeclampsia and seizures in pregnancy.

Form/dose: Clinically administered IV. Epsom salts are widely available in stores.

Contraindications: IV use not to be administered outside of clinical supervision due to risk of magnesium toxicity. Contraindicated in patients with severe renal conditions. 

Magnesium bound to taurine, an essential amino acid involved in endothelial function, nitric oxide production, renin-angiotensin system, and oxidative stress.¹³ Mg taurate is effective in reducing high blood pressure, maintaining heart rhythm, and supporting overall cardiovascular function.¹⁴

It is recommended for cardiovascular health, particularly reducing high blood pressure and arrhythmia, and improving nitric oxide production and antioxidant capacity. A 2024 study found that Mg taurate supplementation reduced cortisol levels and high blood pressure while significantly increasing serum magnesium.¹⁵

Forms: Capsules, tablets.

Contraindications: Generally well tolerated.

Magnesium bound to lactic acid, a compound produced naturally in the body during metabolism. Generally found to be gentle on the gastrointestinal tract and often used in slow-release formulations due to good tolerability. A 2021 animal study suggested that low-dose Mg lactate intake had a beneficial health effect on some skeletal muscles and the myocardium by decreasing cellular calcium and increasing cellular magnesium.¹⁶

Forms: Tablets. Often part of formulations alongside other magnesium forms. 

Contraindications: Standard.

Magnesium bound to orotic acid, a precursor involved in pyrimidine and DNA/RNA synthesis. Orotic acid supports myocardial energy and glycogen metabolism during ischemic stress, because damaged heart tissue increases demand for nucleotide synthesis to repair itself and rebuild glycogen stores.
Recent research is lacking, but a 2015 study concluded that Mg orotate may be effective in treating mitral valve prolapse (MVP) and in preventing and treating cardiac arrhythmias, regulating blood pressure, and supporting the autonomic nervous system.¹⁷ Older research suggests that Mg orotate facilitates the transportation of magnesium across cell membranes and into cardiac myocytes.¹⁸

Forms: Capsules, tablets. Studies have used 3 g/day.

Contraindications: Standard.

When choosing a magnesium product, first consider your needs and what you want to achieve.

Compare different products by reading the ingredient label carefully.

• The amount of elemental magnesium: this is the actual dose of magnesium.
• The carrier/form named (glycinate, citrate, oxide, etc.) Organic and chelated forms are well absorbed, while inorganic forms such as oxide are poorly absorbed. 
• Remember that the RDA for total magnesium intake is 310-320 mg/day for adult women and 400-420 mg/day for adult men. The Tolerable Upper Intake Level (UL) is 350 mg/day for adults to avoid gastrointestinal side effects such as diarrhea.
• Check for excipients (fillers and binders).