Magnesium

Yes. Magnesium can reduce absorption of oral bisphosphonates and form insoluble complexes with tetracycline and quinolone antibiotics; separate doses by hours. Loop and thiazide diuretics increase magnesium loss, while potassium-sparing diuretics reduce excretion. Long-term proton pump inhibitors can cause low magnesium levels. — per the NIH Office of Dietary Supplements; general information, not medical advice.

The cheapest magnesium we track works out to $0.03 per serving, against a typical $0.18 across the 109 we can price per dose — about $0.91 a month at the cheapest. That is real cost per dose from live Amazon US prices, not the sticker price. The full ranking is on the Best Magnesium page.

Magnesium Oxide 400mg, 500 Capsules | Elemental Form for Max Concentration… at $0.03 per serving — the lowest cost-per-dose magnesium in our catalog. See the full ranking on the Best Magnesium page.

We're tracking 180 active Magnesium deals across Amazon US and partner retailers, ranked by community votes and cost-per-dose — not paid placement.

Across the 109 Magnesium deals we can price per dose (combination products are left out — their single label dose belongs to whichever ingredient the product is built around) the median cost-per-dose is $0.183; the cheapest quartile comes in under $0.087 per serving. Anything below the median is a solid deal for the same molecule.

Deals are submitted by the community and ranked by net votes (hot minus cold) plus cost-per-dose normalised across container sizes. We take no affiliate kickbacks for ordering; sponsored slots, when present, are clearly badged.

Too much magnesium from food does not pose a health risk in healthy individuals because the kidneys eliminate excess amounts, but high doses from dietary supplements or medications often cause diarrhea, nausea, and abdominal cramping. The Tolerable Upper Intake Level (UL) for supplemental magnesium is 350 mg/day for adults — per the NIH Office of Dietary Supplements.

Magnesium is widely distributed in plant and animal foods and in beverages, with green leafy vegetables (e.g., spinach), legumes, nuts, seeds, and whole grains being good sources; in general, foods that contain dietary fiber provide magnesium, and it is also added to some fortified breakfast cereals. Among the richest selected foods listed are roasted pumpkin seeds (156 mg per ounce, 37% DV), chia seeds (111 mg per ounce), dry-roasted almonds (80 mg per ounce), and boiled spinach (78 mg per half cup) — per the NIH Office of Dietary Supplements.

Labels often show the magnesium COMPOUND weight, not elemental magnesium. By weight, magnesium oxide is about 60% elemental while orotate is only about 7% — so a "1,000 mg orotate" product delivers roughly 70 mg of elemental magnesium. Compare the "Magnesium" line in the Supplement Facts panel, not the front-of-bottle number.