{
  "name": "Magnesium Glycinate 400 mg: Label Census and Cost per 400 mg Elemental Magnesium",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "priceNote": "Every price and cost here is the brand list price (priceUsd = listPriceUsd), not an Amazon price; prices on Amazon differ. QA round 2, 2026-10-15.",
  "attribution": "Verified Supplement Data, https://verifiedsupplementdata.com/magnesium/glycinate-400-mg/",
  "dateModified": "2026-10-15",
  "note": "One label set across the site (2026-10-15): the labels sold as magnesium glycinate that list glycinate or bisglycinate on the Supplement Facts panel. Cost per 400 mg is a unit for comparing labels that print 400 mg, not a recommended dose (NIH upper limit for supplements: 350 mg a day).",
  "methodology": "Labels sold as magnesium glycinate that list glycinate or bisglycinate on the Supplement Facts panel; the Magnesium row is elemental mg per serving; per unit = per serving / units per serving. Every figure was recomputed in two halves split by label-id parity; figures that did not agree within 8 points (shares) or 25% (medians) are not published.",
  "saltWeight": {
    "compound": "magnesium bisglycinate C4H8MgN2O4",
    "molarMass": 172.42,
    "magnesiumAtomicMass": 24.305,
    "magnesiumFractionPct": 14.1,
    "elementalMgIn400MgCompound": 56,
    "compoundMgFor400MgElemental": 2840,
    "note": "The Supplement Facts row named Magnesium is elemental by US regulation; the front label may print either number."
  },
  "limits": {
    "rdaAdultsMg": {
      "min": 310,
      "max": 420,
      "note": "by age and sex, from all sources"
    },
    "rdaWomenMg": 320,
    "rdaMenMg": 420,
    "rdaWomenMenNote": "adults 31 and older (old keys, kept)",
    "supplementalUpperLimitMg": 350,
    "source": "NIH Office of Dietary Supplements, Magnesium Fact Sheet for Health Professionals"
  },
  "labelCensus": {
    "source": "NIH Dietary Supplement Label Database",
    "sourceUrl": "https://dsld.od.nih.gov/",
    "retrievedOn": "2026-08-27",
    "labelsRetrieved": 827,
    "brands": 38,
    "namedGlycinate": null,
    "oldKeysNote": "Kept for readers of the old keys (2026-10-15). Census keys set to null were retired when the site moved to one label set (labels with glycinate or bisglycinate on the panel); see the populated keys beside them.",
    "anyGlycinateRow": {
      "n": 149,
      "medianElementalMgPerServing": 250,
      "p25ElementalMgPerServing": 200,
      "p75ElementalMgPerServing": 400,
      "medianElementalMgPerUnit": 111,
      "atLeast400MgPerServingPct": 32.9,
      "atLeast200MgPerServingPct": 78.5,
      "below120MgPerServingPct": 10.1,
      "twoPlusUnitsPerServingPct": 78.5,
      "validation": {
        "method": "split-half by DSLD label-id parity; shares within 8 points, medians within 25%",
        "checked": 10,
        "held": 8,
        "failed": [
          "share blending another magnesium form",
          "share blending magnesium oxide"
        ]
      },
      "notPublished": [
        "share blending another magnesium form",
        "share blending magnesium oxide"
      ]
    }
  },
  "costPer400Mg": [
    {
      "name": "BulkSupplements Magnesium Glycinate Powder (500 g)",
      "brand": "BulkSupplements.com",
      "elementalMgPerServing": 300,
      "servingSize": "2.2 g powder (3/4 tsp)",
      "servingsPerContainer": 227,
      "elementalMgPerUnit": null,
      "unitsPer400Mg": null,
      "daysOf400MgPerContainer": 170,
      "priceUsd": 21.97,
      "listPriceUsd": 21.97,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 22.97,
      "costPer400MgElementalUsd": 0.257,
      "costPer300MgElementalUsdAtListPrice": 0.193,
      "unitsAtOrUnder350Mg": null,
      "certification": "NSF/ANSI 173 (glycinate + oxide blend)",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Nutricost Magnesium Glycinate 210 mg (360 capsules)",
      "brand": "Nutricost",
      "elementalMgPerServing": 210,
      "servingSize": "3 capsules",
      "servingsPerContainer": 120,
      "elementalMgPerUnit": 70,
      "unitsPer400Mg": 6,
      "daysOf400MgPerContainer": 63,
      "priceUsd": 24.97,
      "listPriceUsd": 24.97,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 21.95,
      "costPer400MgElementalUsd": 0.396,
      "costPer300MgElementalUsdAtListPrice": 0.297,
      "unitsAtOrUnder350Mg": 5,
      "certification": "None stated (third-party tested claim)",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Doctor's Best High Absorption Magnesium",
      "brand": "Doctor's Best",
      "elementalMgPerServing": 200,
      "servingSize": "2 tablets",
      "servingsPerContainer": 120,
      "elementalMgPerUnit": 100,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 60,
      "priceUsd": 23.99,
      "listPriceUsd": 23.99,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 23.99,
      "costPer400MgElementalUsd": 0.4,
      "costPer300MgElementalUsdAtListPrice": 0.3,
      "unitsAtOrUnder350Mg": 3,
      "certification": "None",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "NOW Magnesium Bisglycinate Powder (8 oz)",
      "brand": "NOW Foods",
      "elementalMgPerServing": 250,
      "servingSize": "1 level teaspoon (~2.9 g)",
      "servingsPerContainer": 78,
      "elementalMgPerUnit": null,
      "unitsPer400Mg": null,
      "daysOf400MgPerContainer": 48,
      "priceUsd": 23.99,
      "listPriceUsd": 23.99,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 11.99,
      "costPer400MgElementalUsd": 0.421,
      "costPer300MgElementalUsdAtListPrice": 0.316,
      "unitsAtOrUnder350Mg": null,
      "certification": "NPA GMP Certified, Non-GMO Project Verified",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "NOW Magnesium Glycinate 200 mg (tablets)",
      "brand": "NOW Foods",
      "elementalMgPerServing": 200,
      "servingSize": "2 tablets",
      "servingsPerContainer": 120,
      "elementalMgPerUnit": 100,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 60,
      "priceUsd": 31.99,
      "listPriceUsd": 31.99,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 26.12,
      "costPer400MgElementalUsd": 0.711,
      "costPer300MgElementalUsdAtListPrice": 0.533,
      "unitsAtOrUnder350Mg": 3,
      "certification": "NPA GMP Certified",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Thorne Magnesium Glycinate (90 capsules)",
      "brand": "Thorne",
      "elementalMgPerServing": 120,
      "servingSize": "1 capsule",
      "servingsPerContainer": 90,
      "elementalMgPerUnit": 120,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 27,
      "priceUsd": 26,
      "listPriceUsd": 26,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 26,
      "costPer400MgElementalUsd": 0.963,
      "costPer300MgElementalUsdAtListPrice": 0.722,
      "unitsAtOrUnder350Mg": 2,
      "certification": "NSF/ANSI 173",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Nature Made Magnesium Glycinate 200mg",
      "brand": "Nature Made",
      "elementalMgPerServing": 200,
      "servingSize": "2 capsules",
      "servingsPerContainer": 30,
      "elementalMgPerUnit": 100,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 15,
      "priceUsd": 21.99,
      "listPriceUsd": 21.99,
      "priceBasis": "brand list price",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 11.7,
      "costPer400MgElementalUsd": 1.466,
      "costPer300MgElementalUsdAtListPrice": 1.1,
      "unitsAtOrUnder350Mg": 3,
      "certification": "USP Verified",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Vitamin Shoppe Magnesium Glycinate 400 mg (135 tablets)",
      "brand": "The Vitamin Shoppe",
      "elementalMgPerServing": 400,
      "servingSize": "3 tablets",
      "servingsPerContainer": 45,
      "elementalMgPerUnit": 133,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 45,
      "priceUsd": null,
      "listPriceUsd": null,
      "priceBasis": "no list price we could check",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 19.99,
      "costPer400MgElementalUsd": null,
      "costPer300MgElementalUsdAtListPrice": null,
      "unitsAtOrUnder350Mg": 2,
      "certification": "None",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "KAL Magnesium Glycinate 350 mg (240 VegCaps)",
      "brand": "KAL",
      "elementalMgPerServing": 350,
      "servingSize": "4 VegCaps",
      "servingsPerContainer": 60,
      "elementalMgPerUnit": null,
      "unitsPer400Mg": null,
      "daysOf400MgPerContainer": 52,
      "priceUsd": null,
      "listPriceUsd": null,
      "priceBasis": "no list price we could check",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 24.79,
      "costPer400MgElementalUsd": null,
      "costPer300MgElementalUsdAtListPrice": null,
      "unitsAtOrUnder350Mg": null,
      "certification": "None",
      "nihDsldId": null,
      "availability": "ok"
    },
    {
      "name": "Nature's Bounty High Absorption Magnesium Glycinate 240 mg (120 capsules)",
      "brand": "Nature's Bounty",
      "elementalMgPerServing": 240,
      "servingSize": "2 capsules",
      "servingsPerContainer": 60,
      "elementalMgPerUnit": 120,
      "unitsPer400Mg": 4,
      "daysOf400MgPerContainer": 36,
      "priceUsd": null,
      "listPriceUsd": null,
      "priceBasis": "no list price we could check",
      "priceCheckedOn": "2026-10-14",
      "priceVerifiedOn": "2026-11-06",
      "amazonPriceUsd": 15.97,
      "costPer400MgElementalUsd": null,
      "costPer300MgElementalUsdAtListPrice": null,
      "unitsAtOrUnder350Mg": 2,
      "certification": "None",
      "nihDsldId": null,
      "availability": "ok"
    }
  ]
}