Written by Ansley Hill, RD, LD on November 21, 2019 — Medically reviewed by Adda Bjarnadottir, MS, RDN (Ice)

Magnesium is the fourth most abundant mineral in your body.

It’s involved in over 300 metabolic reactions that are essential for human health, including energy production, blood pressure regulation, nerve signal transmission, and muscle contraction.

Interestingly, low levels are linked to a variety of illnesses, such as type 2 diabetes, heart disease, mood disorders, and migraines.

Although this mineral is present in many whole foods like green leafy vegetables, legumes, nuts, and seeds, up to two-thirds of people in the Western world don’t meet their magnesium needs with diet alone.

To boost intake, many people turn to supplements. However, as multiple varieties of supplemental magnesium exist, it can be difficult to know which one is most appropriate for your needs.

This article reviews 10 various forms of magnesium, as well as their uses.

1. Magnesium citrate

Magnesium citrate is a form of magnesium that’s bound with citric acid.

This acid is found naturally in citrus fruits and gives them their tart, sour flavor. Artificially produced citric acid is often used as a preservative and flavor enhancer in the food industry.

Magnesium citrate is one of the most common magnesium formulations and can be easily purchased online or in stores worldwide.

Some research suggests that this type is among the most bioavailable forms of magnesium, meaning that it’s more easily absorbed in your digestive tract than other forms.

It’s typically taken orally to replenish low magnesium levels. Due to its natural laxative effect, it’s also sometimes used at higher doses to treat constipation.

What’s more, it’s occasionally marketed as a calming agent to help relieve symptoms associated with depression and anxiety, but more research is needed on these uses.

2. Magnesium oxide

Magnesium oxide is a salt that combines magnesium and oxygen.

It naturally forms a white, powdery substance and may be sold in powder or capsule form. It’s also the main active ingredient in milk of magnesia, a popular over-the-counter medication for constipation relief.

This type isn’t typically used to prevent or treat magnesium deficiencies, as some studies report that it’s poorly absorbed by your digestive tract.

Instead, it’s more frequently used for short-term relief of uncomfortable digestive symptoms, such as heartburn, indigestion, and constipation. It may also be used to treat and prevent migraines.

3. Magnesium chloride

Magnesium chloride is a magnesium salt that includes chlorine — an unstable element that binds well with other elements, including sodium and magnesium, to form salts.

It’s well absorbed in your digestive tract, making it a great multi-purpose supplement. You can use it to treat low magnesium levels, heartburn, and constipation.

Magnesium chloride is most frequently taken in capsule or tablet form but also sometimes used in topical products like lotions and ointments.

Although people use these skin creams to soothe and relax sore muscles, little scientific evidence links them to improved magnesium levels.