Magnesium glycinate: potential benefits, possible risks and what to know

If you have ever looked for a better way to sleep or something gentle to help you relax after a stressful day, you have likely come across magnesium glycinate.

It has become a common part of bedtime routines, supplement shelves and social media claims that link it to calmer nerves and fewer muscle cramps.

Experts, however, say taking it will not automatically improve your health — although it may help people who do not get enough magnesium from food or who have a known or suspected deficiency, says Jen Messer, a researcher, registered dietitian and former president of the New Hampshire Academy of Nutrition and Dietetics.

The important part, she says, is knowing what it can and cannot do, whether you truly need it, and how to use it safely. Here is what to know.

What is magnesium glycinate?

Magnesium glycinate, also known as magnesium bisglycinate, is a supplement sold in pill, powder or liquid form, Messer explains. It combines the essential mineral magnesium with glycine, an amino acid the body produces and uses to make proteins.

Other forms combine magnesium with different compounds, such as magnesium citrate, which is a salt of citric acid, or magnesium oxide, which pairs magnesium with oxygen.

“But magnesium glycinate is generally well-absorbed and tends to be easier on the digestive system than these other forms, which is one reason it is often chosen for people who experience stomach issues with other magnesium supplements,” says Amy Goodson, a registered dietitian and founder of The Sports Nutrition Playbook.

As for natural sources, Goodson says magnesium glycinate itself does not occur in foods and is a manufactured supplement rather than something the body makes. Still, Messer adds, dietary magnesium is found in green leafy vegetables, nuts, seeds, legumes, whole grains and some fish.

Even though magnesium is available in many foods, not everyone gets enough. A New England Journal of Medicine review estimates that hypomagnesemia, or low magnesium levels in the blood, affects about 3% to 10% of the general population. “But this is more common in certain groups,” Messer says, including people with type 2 diabetes; people taking medications such as proton-pump inhibitors, some diuretics and certain chemotherapy drugs; and those with alcohol dependence, chronic diarrhea or disorders that affect nutrient absorption.

Low magnesium can lead to symptoms such as muscle cramps, fatigue or weakness, but those signs are not unique to magnesium deficiency. Anyone who suspects a deficiency should talk with a health care provider about diet and medications instead of trying to diagnose it themselves, Goodson says.

What can magnesium glycinate do?

Although magnesium glycinate has been studied less extensively than magnesium overall, Goodson says magnesium remains an essential nutrient because it supports normal muscle and nerve function, blood pressure control, blood glucose regulation and energy production. Correcting a shortage can help those systems work normally, Messer says, but taking extra magnesium will not improve them if you already get enough.

Magnesium is often linked with better sleep or falling asleep more quickly, but Messer says the evidence is limited.

Research on stress and anxiety is also still early, though Goodson says supplementation may modestly improve anxiety symptoms in some people, especially when their magnesium intake or status is low.

Supplemental magnesium, not magnesium glycinate specifically, may also lower migraine frequency in some people, Messer says, although the U.S. National Institutes of Health advises that magnesium for migraine prevention should be used under medical supervision.

Is magnesium glycinate safe?

Magnesium glycinate is generally well tolerated, but safety and absorption depend on the dose, kidney health and medications.

Magnesium supplements are often easier on the stomach, but glycinate can still cause side effects. In fact, its most common side effects are gastrointestinal, Messer says, including diarrhea, nausea and abdominal cramping, especially at higher doses.

“Excess magnesium can also become dangerous in people with impaired kidney function,” Goodson says. If the kidneys cannot clear enough magnesium, it can build up and may cause low blood pressure, abnormal heart rhythms and other complications.

Messer also cautions that magnesium can interfere with certain antibiotics and osteoporosis medications by reducing absorption, although a pharmacist can help determine whether doses should be spaced apart and by how long.

For dosing, the NIH says non-pregnant adult women generally need 310 to 320 milligrams per day and men need 400 to 420 milligrams per day, depending on age. Those numbers reflect total daily intake from food and supplements combined, not the amount you should necessarily take in supplement form. Goodson recommends checking the amount of elemental magnesium listed on the Supplement Facts panel of any magnesium product you use. Keep in mind that this refers to magnesium itself, not the full weight of the magnesium-glycine compound.

Because symptomatic deficiency is uncommon in otherwise healthy people and many of the claimed benefits are still uncertain, supplementation is not usually recommended.

“Typically, the only time it makes sense to take a micronutrient supplement, including magnesium glycinate,” Messer says, “is when you have a confirmed deficiency or a specific reason for why you may not be meeting your needs.”