Comprehensive medication guide to Magnesium Aspartate including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
Magnesium aspartate is an OTC dietary supplement and is not covered by standard health insurance, Medicare Part D, or most Medicaid plans. HSA or FSA accounts may be used with a Letter of Medical Necessity from a physician.
Estimated Cash Pricing
$10–$25 per month for generic magnesium aspartate; $20–$40 for Maginex brand (100 tablets). Prices are lower through online retailers like Amazon, iHerb, and Vitacost.
Medfinder Findability Score
90/100
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Magnesium aspartate is a dietary supplement that combines magnesium — an essential mineral — with L-aspartic acid, an amino acid. Its chemical formula is Mg(C4H6NO4)2(H2O)2. It is available over the counter under the brand names Maginex (tablet) and Maginex DS (dissolvable powder). Generic versions are also widely sold.
Magnesium is involved in over 300 enzymatic reactions in the body, including energy production (ATP synthesis), protein synthesis, DNA replication, muscle contraction, nerve impulse conduction, blood pressure regulation, and blood glucose metabolism. About 60% of the body's magnesium is stored in bones, with the rest distributed in soft tissues and blood.
What sets magnesium aspartate apart from most other magnesium supplement forms is its superior bioavailability — estimated at approximately 40% absorption, compared to just 4% for magnesium oxide, which is the most commonly sold but least effective form. Magnesium aspartate is manufactured by Geist Pharm LLC (Maginex brand) and is also available from numerous generic supplement manufacturers.
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Magnesium aspartate works by supplying bioavailable magnesium ions (Mg2+) to the body. Once ingested, the tablet or powder dissolves in the stomach and the magnesium-aspartate compound is absorbed through the small intestine. L-aspartate, as a Krebs cycle intermediate, facilitates the efficient transport of magnesium across intestinal cell membranes, contributing to its high bioavailability compared to inorganic forms like oxide or carbonate.
Once in the bloodstream, magnesium ions are distributed to cells throughout the body. Magnesium serves as a cofactor for hundreds of enzymes. Key mechanisms include: activation of ATP molecules (every ATP must be bound to magnesium to be biologically active), modulation of NMDA receptor channels (affecting neuronal excitability and mood), regulation of calcium ion channels in muscles and heart cells (controlling contraction and relaxation), and support for glutathione synthesis (the body's primary intracellular antioxidant).
Excess magnesium is regulated and excreted by healthy kidneys, making toxicity rare in patients with normal renal function. People with kidney disease have impaired magnesium excretion and require medical supervision when supplementing.
615 mg MAH per tablet — tablet
Maginex — each tablet contains 615 mg magnesium-L-aspartate hydrochloride. Typical dose: 2 tablets up to 3x daily.
Varies by brand — powder/granules
Maginex DS — dissolvable powder. Mix in 50-200 mL water, tea, or orange juice.
250–500 mg elemental Mg — capsule (generic)
Generic magnesium aspartate capsules available from various manufacturers. Elemental magnesium content varies — check supplement facts label.
Magnesium aspartate is generally widely available, particularly through online retailers. However, local pharmacies — especially chain pharmacies like CVS, Walgreens, and Rite Aid — do not always stock it, as they prioritize higher-volume magnesium supplement forms like magnesium oxide. As of 2026, there is no FDA-declared shortage of magnesium aspartate. Patients with normal access to online shopping will find consistent availability.
The main challenge is local pharmacy availability of the Maginex brand specifically. Independent pharmacies are more likely to carry it or order it on request. Big-box retailers like Walmart and Costco sometimes carry generic magnesium aspartate at competitive prices. Online retailers (Amazon, iHerb, Vitacost) reliably stock both Maginex and generic brands.
If you're having trouble locating it at a pharmacy near you, use medfinder — we call pharmacies on your behalf to find which ones have it in stock, then text you the results.
Magnesium aspartate does not require a prescription — it is an OTC dietary supplement available to anyone without a doctor's order. However, a physician recommendation or Letter of Medical Necessity can unlock HSA/FSA eligibility and enable access to certain pharmacy channels. Any licensed healthcare provider can recommend magnesium aspartate for appropriate patients.
Telehealth platforms (Teladoc, MDLive, HealthTap) offer convenient access to providers who can review your magnesium status, order lab work if needed, and provide a Letter of Medical Necessity for HSA/FSA reimbursement — often with same-day or next-day availability.
No. Magnesium aspartate is not a controlled substance. It is classified as a dietary supplement by the FDA, not as a prescription medication or scheduled drug. The Drug Enforcement Administration (DEA) has no scheduling classification for magnesium aspartate.
Because magnesium aspartate is an OTC supplement, you can purchase it without a prescription at pharmacies, health food stores, and online. However, medical guidance is recommended for people with kidney disease, heart conditions, or those taking medications that interact with magnesium (such as tetracycline antibiotics, bisphosphonates, or levothyroxine). Always tell your healthcare provider about all supplements you take.
Magnesium aspartate is generally well tolerated. Common side effects, typically related to gastrointestinal effects at higher doses, include:
Serious side effects are rare with oral supplementation in people with healthy kidneys. Signs of magnesium toxicity (hypermagnesemia) include:
People with kidney disease are at significantly higher risk for toxicity and should only use magnesium supplements under physician supervision.
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Magnesium Glycinate
Highly bioavailable, very gentle on the GI tract, no laxative effect. Glycine has calming properties. Best for sleep, anxiety, and general deficiency.
Magnesium Citrate
One of the most widely available and studied forms. Good bioavailability (~30%), mild laxative effect. Best for constipation or when cost and availability are priorities.
Magnesium Malate
Bound to malic acid, another Krebs cycle intermediate — similar biochemical rationale to aspartate. Good for energy and muscle pain. Studied for fibromyalgia.
Magnesium L-Threonate
Crosses the blood-brain barrier; studied for cognitive function. Higher cost, lower elemental magnesium per dose. Best for neurological/cognitive applications, not general deficiency.
Magnesium Chloride
High water solubility and bioavailability. Available in oral and topical forms (sprays, bath flakes). Good option for those who prefer topical supplementation.
Prefer Magnesium Aspartate? We can find it.
Tetracycline antibiotics (doxycycline, tetracycline)
moderateMagnesium chelates tetracyclines in the gut, reducing antibiotic absorption by 50-90%. Separate doses by at least 2 hours (take antibiotic first).
Fluoroquinolone antibiotics (ciprofloxacin, levofloxacin)
moderateSame chelation mechanism as tetracyclines. Magnesium significantly reduces fluoroquinolone absorption. Separate by at least 2 hours.
Oral bisphosphonates (alendronate/Fosamax, risedronate)
moderateMagnesium reduces bisphosphonate absorption. Separate by at least 2 hours. Does not apply to injectable bisphosphonates.
Levothyroxine (Synthroid)
moderateMagnesium may reduce thyroid hormone absorption. Separate by at least 2-4 hours. Take levothyroxine first thing in the morning.
Gabapentin (Neurontin)
moderateMagnesium can lower gabapentin blood levels by 20-40% if taken simultaneously. Separate doses by at least 2 hours.
Thiazide/loop diuretics (hydrochlorothiazide, furosemide)
moderateThese diuretics increase urinary magnesium excretion, potentially creating or worsening magnesium deficiency. Monitor magnesium levels.
Proton pump inhibitors (omeprazole, pantoprazole)
minorLong-term PPI use associated with significant magnesium depletion. FDA has issued a safety communication about this risk.
Calcium channel blockers (amlodipine, verapamil)
minorMagnesium acts as a natural calcium channel blocker; additive blood pressure lowering may occur. Monitor blood pressure.
Digoxin
moderateMagnesium affects heart rhythm and may alter digoxin effects. Monitor levels closely if both are used.
Calcium supplements (high dose)
minorHigh-dose calcium can compete with magnesium absorption. Separate doses by a few hours.
Magnesium aspartate stands out among magnesium supplements for its exceptional bioavailability, tolerability, and the added biochemical benefit of the aspartate carrier. For patients with documented magnesium deficiency, cardiovascular conditions requiring electrolyte support, chronic fatigue, or drug-induced magnesium depletion, it represents a clinically well-supported choice.
While it may not be on every pharmacy shelf, it is widely accessible through online retailers and can be ordered by independent pharmacies. The most important consideration for patients is verifying dosing (look at elemental magnesium content on the label), timing doses away from interacting medications, and taking it with food to minimize GI effects.
If you're struggling to find magnesium aspartate at a pharmacy near you, medfinder can help. We call pharmacies on your behalf to find which ones have your medication in stock, and send you the results by text — saving you the time and frustration of calling around yourself.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
Real-time availability
Medfinder is actively checking pharmacy inventory for Magnesium Aspartate. We don't publish a number until we have enough verified pharmacy checks to be accurate — start a search and our team confirms current availability near you, usually within 24 hours.
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