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magnesium l-threonate

Magnesium L-Threonate (Magnesium) is a dietary supplement.

Magnesium

Not yet rated· sourced from the FDA label
Rated against independent regulatory sources·Last updated June 23, 2026·How we rate
Verified againstopenFDANIH DailyMedRxClass
$0.01 /mL
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Key facts

Active ingredient
Magnesium
Type
Supplement
What the pharmacy pays
~$0.01 per ml — not your price

What the evidence says

Limited evidence

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it raises magnesium levels in the brain, but US government health agencies (NIH Office of Dietary Supplements, NCCIH) do not publish a fact sheet evaluating this specific form, so claims unique to L-threonate are not supported by those authorities.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.

Drug class

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Frequently asked questions

How much does Magnesium L-Threonate cost?
Nobody can tell you what you will pay — your price is set by your insurer's formulary, your deductible and the pharmacy's markup, and none of those are published. What IS published is what the pharmacy paid to acquire it: about $0.01 per ml, per the CMS NADAC survey. Treat that as the floor, not the quote — ask the pharmacist for the cash price as well as your copay, because for cheap generics the cash price often wins.
What class of drug is Magnesium L-Threonate?
Magnesium L-Threonate is classified as calculi dissolution agent, osmotic laxative, per the FDA's Established Pharmacologic Class.

Information is sourced from public FDA regulatory data. Provided for general reference only — not medical advice. Always consult a licensed professional and the current prescribing information.

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