Magnesium Supplements Crash Course (2026): Benefits and Side Effects

“It’s really overlooked that magnesium can help with menstrual cycle irregularity in terms of making sure that you’re not having severe cramping,” says Anderson-Haynes, who adds it may also benefit women in perimenopause and menopause. Clinically, it may be part of the treatment for pregnancy complications like preeclampsia and eclampsia.

Can You Take Too Much?

The recommended dietary allowance is 320 milligrams per day for women and 420 milligrams per day for men. These are amounts most people can reach with a balanced diet; healthy kidneys regulate magnesium levels, excreting excess when magnesium intake is high and conserving it when it’s low.

Daily supplements under 350 milligrams are generally considered safe for healthy adults. “If you take too much magnesium, you’ll probably get diarrhea, because it loosens the bowels,” Anderson-Haynes says. Other side effects include nausea, gastrointestinal discomfort, and, at very high levels of magnesium (usually from overusing laxatives or antacids), low blood pressure, muscle cramps, breathing problems, and, in rare cases, cardiac arrest. People with kidney disease are at the highest risk of toxicity.

Should You Supplement?

For most healthy U.S. adults, magnesium supplements aren’t essential. If you struggle with migraines, insomnia, or other conditions where research suggests health benefits, they may be worth trying—but first talk to a health care professional.

Otherwise, focus on magnesium-rich foods. These include but are not limited to: legumes (beans, lentils, chickpeas), leafy greens (artichokes, kale, spinach), whole grains (oats, barley, quinoa), nuts (almonds, cashews, peanuts), fruit (bananas, avocado, dried apricots), and soy products (tofu, soy milk, edamame). Dark chocolate is also a good source of magnesium; 100 grams of 70-85 percent of cacao solids contain 228 milligrams of magnesium, which is more than half of the amount of magnesium recommended for daily intake.

If you do decide to take any dietary supplements, “look for a seal or certification that says GMP (Good Manufacturing Practices) or NSF,” says Anderson-Haynes, stressing the importance of third-party tests and verifications, considering the Food and Drug Administration (FDA) doesn’t regulate dietary supplements in the US.

Our Favorite Magnesium Supplements

Pure Encapsulations was recommended to me by my doctor, and it seems to be the company that health care professionals trust the most. I prefer capsules over powders when it comes to magnesium glycinate because I’m taking these right before bed and usually can’t stomach a liquid concoction. Each capsule contains 120 milligrams, and you can take one to four capsules a day depending on what your doctor recommends.

While magnesium glycinate is often taken for sleep and a better mood, it also supports heart health, cellular energy production, and bone structure. It’s also less likely to have a laxative effect if you’re usually sensitive to magnesium supplements. Pure Encapsulations sells several forms of magnesium, in capsule, powder, and liquid form.

Thorne

Magnesium Bisglycinate

Thorne (NSF Certified for Sport) is one of the brands we trust the most when it comes to dietary supplements, mostly because they rigorously test their products for potency, purity, and label accuracy through every step of the process. They screen raw materials for contaminants in their in-house laboratories. They check the supplements, including the bottles and labels, for defects. Before hitting the shelves, they ensure that no microbiological contamination has occurred during the manufacturing process. Lastly, products undergo stability testing to confirm that they will meet their label claims up to the expiration date.

Thorne also offers travel packs, capsules, multivitamins that contain magnesium, and other forms of magnesium, including Magnesium CitraMate, which is a blend of magnesium citrate and di-magnesium malate.

Buoy

Rainforest Activated Magnesium

Many health care providers have drilled into me that you should get nutrients, like magnesium, from food as opposed to supplements. Like most people, I have trouble getting enough leafy greens and seeds in my diet. Buoy’s Rainforest Activated Magnesium does the job (and adds a minty undertone to my morning smoothies). This magnesium powder is formulated with plants sourced from the Australian rainforest, including anise myrtle, shiitake mushrooms, and pumpkin seed meal. Theoretically, these aid in better absorption and make the supplement more metabolically useful. I’m still following the doctor’s orders of using food sources, and I sleep more deeply when regularly using it. —Julia Forbes

Meet the Experts

• Sue-Ellen Anderson-Haynes, MS, RDN, CDCES, is a spokesperson for the Academy of Nutrition and Dietetics and founder of 360Girls&Women.

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