What Magnesium L-Threonate is
Magnesium L-threonate is a supplemental form of the essential mineral magnesium, in which magnesium is bound to threonic acid (a sugar-acid derived from vitamin C). Magnesium itself is a nutrient the body needs for many processes, including regulating muscle and nerve function, blood sugar levels, and blood pressure, and for making protein, bone, and DNA. The L-threonate form is marketed largely on the claim that it raises magnesium levels in the brain, but US government health agencies (NIH Office of Dietary Supplements, NCCIH) do not publish a fact sheet evaluating this specific form, so claims unique to L-threonate are not supported by those authorities.
Commonly used for
Marketed to support memory, learning, and cognitive functionTaken for sleep and relaxationUsed as a general magnesium supplementSometimes used for migraine preventionPromoted for age-related cognitive decline
What the evidence shows
There is no authoritative US-government evaluation of magnesium L-threonate's headline use for memory or cognition, so the rigorous evidence behind those marketing claims is limited. For magnesium more broadly, NCCIH notes that for sleep "there isn't enough rigorous scientific evidence to determine whether they are effective," and that for type 2 diabetes "results from clinical trials have not shown a clear benefit." For migraine, NIH ODS notes that "several small studies found that magnesium supplements can modestly reduce the frequency of migraines" but that "more research is needed," and NCCIH cautions that the typical doses studied exceed the safe upper intake level and should be used only under a provider's supervision. None of these evaluations addresses the L-threonate form specifically.
Typical dosage
There is no government-established dose for the L-threonate form specifically; product labels commonly provide 1,000-2,000 mg of the compound, which corresponds to a smaller amount of elemental magnesium. For supplemental magnesium generally, the NIH Tolerable Upper Intake Level from dietary supplements and medications is 350 mg/day of elemental magnesium for adults. Doses studied for conditions like migraine routinely exceed this, and per NCCIH such treatment "should be used only under the direction and supervision of a health care provider." Talk to your doctor or pharmacist before starting this supplement, especially if you have kidney disease, are pregnant, or take other medications.
Safety
Magnesium naturally present in food and beverages is not harmful for healthy people, because the kidneys clear any excess in urine; however, magnesium from dietary supplements and medications should not be taken above the upper limit unless a health care provider recommends it. Per the NIH Office of Dietary Supplements, "High intakes of magnesium from dietary supplements and medications can cause diarrhea, nausea, and abdominal cramping," and "Extremely high intakes of magnesium can lead to irregular heartbeat and cardiac arrest." People with kidney problems are at higher risk of magnesium buildup and should be especially cautious. Because the L-threonate form has not been evaluated by NIH ODS or NCCIH, its long-term safety is not established by these authorities.
Side effects
According to the NIH Office of Dietary Supplements, high intakes of supplemental magnesium can cause diarrhea, nausea, and abdominal cramping. Extremely high intakes can lead to an irregular heartbeat and, in severe cases, cardiac arrest. These effects are tied to total elemental magnesium intake rather than to the threonate form specifically.
Interactions & cautions
Magnesium supplements can interact with certain medications. The NIH Office of Dietary Supplements notes that magnesium can interfere with the absorption of some antibiotics and of bisphosphonates used for osteoporosis when taken too close together, so these are usually spaced apart in time. Diuretics can either increase or decrease magnesium loss through urine depending on the type, and long-term use of prescription acid-reflux drugs (such as proton pump inhibitors) can cause low blood magnesium. Very high doses of zinc can also interfere with how the body absorbs and regulates magnesium. Tell your clinician and pharmacist about all medications and supplements before taking magnesium L-threonate.
This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. Summarized from public health authorities; general reference, not medical advice. Talk to a licensed healthcare professional before starting any supplement.