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Cheapest Magnesium (as magnesium carbonate) on iHerb

Ranked by real cost per 100 mg of Magnesium (as magnesium carbonate) — cheapest value first.

Prices updated Jul 25, 2026 · 25 products · Prices in USD

The priciest option here costs about 3.1× more per 100 mg of Magnesium (as magnesium carbonate) than the best-value pick Nutricost. For the same daily dose, choosing by cost per unit instead of sticker price can meaningfully cut your yearly spend.
#ProductDoseServingsPrice (USD)Cost per 100 mg
1
Nutricost, Magnesium Glycinate, Unflavored , 8.9 oz (250 g)
Nutricost, Magnesium Glycinate, Unflavored , 8.9 oz (250 g)
Nutricost
210 mg13519.950.070View on iHerb →
2
Nutricost, Magnesium Bisglycinate, Unflavored, 8.9 oz (250 g)
Nutricost, Magnesium Bisglycinate, Unflavored, 8.9 oz (250 g)
Nutricost
210 mg13522.950.081View on iHerb →
3
NaturesPlus, KalmAssure®, Magnesium, 240 Vegan Capsules (105 mg Per capsule)
NaturesPlus, KalmAssure®, Magnesium, 240 Vegan Capsules (105 mg Per capsule)
NaturesPlus
420 mg6021.210.084View on iHerb →
4
The Vitamin Shoppe, Calm Zone®, Magnesium, Raspberry Lemon, 16 oz (450 g)
The Vitamin Shoppe, Calm Zone®, Magnesium, Raspberry Lemon, 16 oz (450 g)
The Vitamin Shoppe
325 mg10029.990.092View on iHerb →
5
EVLution Nutrition, Magnesium + L-Theanine, Pink Lemonade, 3.17 oz (90 g)
EVLution Nutrition, Magnesium + L-Theanine, Pink Lemonade, 3.17 oz (90 g)
EVLution Nutrition
200 mg305.970.100View on iHerb →
6
NutriBiotic, Immunity, Ascorbate Bio-C, Vitamin C with Bioflavonoids and Minerals, 2.2 lb (1 kg)
NutriBiotic, Immunity, Ascorbate Bio-C, Vitamin C with Bioflavonoids and Minerals, 2.2 lb (1 kg)
NutriBiotic
75 mg40031.790.106View on iHerb →
7
Natural Vitality, CALM®, Magnesium Supplement Drink Mix, Cherry, 8 oz (226 g)
Natural Vitality, CALM®, Magnesium Supplement Drink Mix, Cherry, 8 oz (226 g)
Natural Vitality
325 mg5620.240.111View on iHerb →
8
NutriBiotic, Immunity, Ascorbate Bio-C, Vitamin C with Bioflavonoids and Minerals, 16 oz (454 g)
NutriBiotic, Immunity, Ascorbate Bio-C, Vitamin C with Bioflavonoids and Minerals, 16 oz (454 g)
NutriBiotic
75 mg18116.500.122View on iHerb →
9
21st Century, Chelated Magnesium Glycinate, 90 Capsules, (100 mg per Capsule)
21st Century, Chelated Magnesium Glycinate, 90 Capsules, (100 mg per Capsule)
21st Century
200 mg4510.990.122View on iHerb →
10
The Vitamin Shoppe, Calm Zone®, Magnesium, Raspberry Lemon, 8 oz (225 g)
The Vitamin Shoppe, Calm Zone®, Magnesium, Raspberry Lemon, 8 oz (225 g)
The Vitamin Shoppe
325 mg5019.990.123View on iHerb →
11
Vthrive, Magnesium Relax, Raspberry Lemon, 8.5 oz (235 g)
Vthrive, Magnesium Relax, Raspberry Lemon, 8.5 oz (235 g)
Vthrive
350 mg5021.990.126View on iHerb →
12
Source Naturals, Magnesium Glycinate, 120 Tablets
Source Naturals, Magnesium Glycinate, 120 Tablets
Source Naturals
200 mg6015.420.129View on iHerb →
13
Nutricost, Magnesium Glycinate, Fruit Punch, 8.9 oz (250 g)
Nutricost, Magnesium Glycinate, Fruit Punch, 8.9 oz (250 g)
Nutricost
210 mg7420.630.133View on iHerb →
14
Nutricost, Magnesium Glycinate, 360 Capsules (70 mg per Capsule)
Nutricost, Magnesium Glycinate, 360 Capsules (70 mg per Capsule)
Nutricost
210 mg12034.660.138View on iHerb →
15
Source Naturals, Magnesium Glycinate, 60 Tablets
Source Naturals, Magnesium Glycinate, 60 Tablets
Source Naturals
200 mg308.400.140View on iHerb →
16
Source Naturals, Magnesium Glycinate , 180 Tablets
Source Naturals, Magnesium Glycinate , 180 Tablets
Source Naturals
200 mg9025.840.144View on iHerb →
17
Life Extension, Effervescent Vitamin C, Magnesium Crystals, 6.35 oz (180 g)
Life Extension, Effervescent Vitamin C, Magnesium Crystals, 6.35 oz (180 g)
Life Extension
250 mg3012.000.160View on iHerb →
18
Nutricost, Calcium & Magnesium, 240 Tablets
Nutricost, Calcium & Magnesium, 240 Tablets
Nutricost
150 mg6014.950.166View on iHerb →
19
Nutricost, Magnesium Glycinate, 180 Capsules (70 mg per Capsule)
Nutricost, Magnesium Glycinate, 180 Capsules (70 mg per Capsule)
Nutricost
210 mg6021.270.169View on iHerb →
20
NutriBiotic, Immunity, Ascorbate Bio-C Powder, Vitamin C With Bioflavonoids And Minerals, 8 oz (227 g)
NutriBiotic, Immunity, Ascorbate Bio-C Powder, Vitamin C With Bioflavonoids And Minerals, 8 oz (227 g)
NutriBiotic
75 mg9011.990.178View on iHerb →
21
Natural Vitality, CALM® Mind, Magnesium Supplement with L-Theanine Drink Mix, Unflavored, 6 oz (168 g)
Natural Vitality, CALM® Mind, Magnesium Supplement with L-Theanine Drink Mix, Unflavored, 6 oz (168 g)
Natural Vitality
200 mg5620.990.187View on iHerb →
22
Natural Vitality, CALM® Mind, Magnesium Supplement with L-Theanine Drink Mix, Honey Chamomile, 6 oz (168 g)
Natural Vitality, CALM® Mind, Magnesium Supplement with L-Theanine Drink Mix, Honey Chamomile, 6 oz (168 g)
Natural Vitality
200 mg5621.000.188View on iHerb →
23
Bluebonnet Nutrition, Magnesium Glycinate, 120 Vegetable Capsules (100 mg per Capsule)
Bluebonnet Nutrition, Magnesium Glycinate, 120 Vegetable Capsules (100 mg per Capsule)
Bluebonnet Nutrition
400 mg3023.960.200View on iHerb →
24
Country Life, High Absorption Dual Action Magnesium Glycinate, 90 Tablets
Country Life, High Absorption Dual Action Magnesium Glycinate, 90 Tablets
Country Life
350 mg3021.490.205View on iHerb →
25
Natural Vitality, CALM, Plus Calcium, Raspberry-Lemon, 8 oz (226 g)
Natural Vitality, CALM, Plus Calcium, Raspberry-Lemon, 8 oz (226 g)
Natural Vitality
320 mg3020.990.219View on iHerb →

How we rank Magnesium (as magnesium carbonate)

Two supplements can list the same dose per serving yet cost very differently once you account for how many servings are in the bottle. We calculate the total nutrient in each container (dose per serving × servings per container), divide the current price by that total, and rank by the resulting cost per unit. Lower is better. Because prices are refreshed automatically, this ranking reflects today's iHerb pricing rather than a snapshot from months ago.

Cost per unit is a starting point, not the whole story — the ideal form, third-party testing, and other ingredients matter too. Always check the label and consult a healthcare professional before starting a supplement.

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Prices update automatically and may differ from iHerb at checkout. Rankings are based on cost per unit of the listed nutrient and are for informational purposes only — not medical advice. Links to iHerb are affiliate links.