Magnesium Glycinate Side Effects | What to Know

Magnesium is the fourth most abundant cation in the human body and a critical cofactor in more than 300 enzyme systems that regulate energy metabolism, neuromuscular function, cardiovascular health, bone integrity, and psychological well-being. Yet studies estimate that between 56 and 68 percent of Americans do not obtain enough Magnesium from their diet to meet the recommended daily allowance.

When choosing a Magnesium supplement, the form matters — not just for absorption but for how your body tolerates it. Magnesium glycinate (bisglycinate) is often recommended for individuals with sensitive digestive systems because it tends to cause fewer gastrointestinal side effects than inorganic forms such as Magnesium oxide. Understanding potential Magnesium glycinate side effects can help you supplement with greater confidence.

Nature's Sunshine Magnesium provides 250 mg of Magnesium per tablet in a blend of Magnesium oxide and Magnesium amino acid chelate, alongside a supportive base of Licorice root, Kelp plant, Peppermint leaves, and White willow bark. If you have questions about which form of Magnesium is best for your situation, our naturopath is available for a free consultation.

Magnesium supplements can cause nausea, cramps, and diarrhea. Magnesium supplements often cause softening of stool and are sometimes used for that purpose. The most common side effects are stomach-related issues, and they usually occur at higher doses.

Side effects are also more common with inorganic forms of Magnesium, such as Magnesium oxide, compared to organic forms like Magnesium glycinate. A meta-analysis found only minor differences in gastrointestinal disturbances between groups given placebo versus 520 mg Magnesium per day, and withdrawals were not significantly different between groups. Another meta-analysis found that 3 of 13 studies (at doses of 120–973 mg/day) reported diarrhea that led to study withdrawal.

This is an important distinction when considering Magnesium glycinate side effects specifically. Because the glycinate form is chelated to the amino acid glycine, its absorption follows the dipeptide transporter pathway, and it tends to be gentler on the digestive tract than oxide or carbonate forms.

Severe Toxicity Is Rare

Hypermagnesemia — excess Magnesium in the blood — from supplemental intake is rare in individuals with normal kidney function because the kidneys efficiently excrete excess Magnesium. Signs of a Magnesium overdose can include nausea, diarrhea, low blood pressure, muscle weakness, and fatigue. At very high doses, Magnesium can be fatal. Risk is substantially elevated in individuals with impaired renal function.

Extra Magnesium from food is considered safe because the kidneys eliminate excess amounts in urine. The Tolerable Upper Intake Level (UL) set by the Food and Nutrition Board is 350 mg from supplements only — importantly, this UL does not include Magnesium found naturally in food and beverages.

Magnesium and drugs use the same transport and metabolism pathways in the body for intestinal absorption, metabolism, and elimination. This means that whenever one or more drugs are taken, there is always a potential risk of interaction with Magnesium status. Being aware of these interactions is an often-overlooked aspect of Magnesium glycinate side effects and safety.

• Bisphosphonates: Magnesium-rich supplements can decrease the absorption of oral bisphosphonates such as alendronate (Fosamax®). Use of Magnesium supplements and oral bisphosphonates should be separated by at least 2 hours.
• Tetracycline and quinolone antibiotics: Magnesium can form insoluble complexes with these antibiotics. The antibiotic should be taken at least 2 hours before or 4–6 hours after Magnesium.
• Diuretics: Loop and thiazide diuretics deplete Magnesium through increased urinary excretion. Potassium-sparing diuretics, such as amiloride and spironolactone, reduce Magnesium loss.
• Proton pump inhibitors (PPIs): When taken for prolonged periods (typically more than a year), PPIs can cause hypomagnesemia. The FDA advises healthcare professionals to consider measuring serum Magnesium levels before initiating long-term PPI treatment.
• Gabapentin: Magnesium may reduce the absorption of gabapentin by 20%, potentially making it less effective.

If you take any of these medications and are considering a Magnesium supplement, we encourage you to speak with your healthcare provider or schedule a free consultation with our naturopath.

Nature's Sunshine Magnesium may be a good fit for adults looking to support nervous system health, bone density, and healthy muscle function. Research suggests that Magnesium is involved in bone formation and influences the activities of osteoblasts and osteoclasts, and it also affects concentrations of parathyroid hormone and the active form of vitamin D — both major regulators of bone homeostasis. Magnesium deficiency can lead to symptoms such as muscle cramps, fatigue, weakness, and cardiovascular abnormalities.

Certain groups are more likely to have inadequate Magnesium intake, including older adults (due to decreased absorption), individuals with gastrointestinal disorders, those with type 2 diabetes, people with alcohol dependence, and individuals on long-term medications such as diuretics or PPIs. Men older than 70 and teenage girls are most likely to have low intakes of Magnesium.

People with impaired kidney function should exercise particular caution because the kidneys play the central role in excreting excess Magnesium. Anyone with kidney disease should consult a healthcare provider before starting any Magnesium supplement.

Take 1 tablet daily with a meal. Each tablet provides 250 mg of Magnesium alongside 40 mg of Calcium and 30 mg of Phosphorus in a supportive base of Licorice root, Kelp plant, Peppermint leaves, and White willow bark.

The Recommended Dietary Allowance (RDA) for Magnesium is 400–420 mg per day for adult men and 310–320 mg per day for adult women. Calcium and Magnesium are nutritional partners and work best when taken together, and vitamin D helps the body better absorb both minerals.