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Cheapest Magnesium on iHerb

Ranked by real cost per 100 mg of Magnesium — cheapest value first.

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

The priciest option here costs about 4.9× more per 100 mg of Magnesium than the best-value pick Vitamatic. 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
Vitamatic, Magnesium Malate Powder, 8.8 oz (250 g)
Vitamatic, Magnesium Malate Powder, 8.8 oz (250 g)
Vitamatic
300 mg25014.990.020View on iHerb →
2
KAL, Dolomite Powder, 16 oz (454 g)
KAL, Dolomite Powder, 16 oz (454 g)
KAL
630 mg9013.690.024View on iHerb →
3
Snap Supplements, Magnesium Complex, 60 Capsules
Snap Supplements, Magnesium Complex, 60 Capsules
Snap Supplements
1,152 mg6016.960.025View on iHerb →
4
Vitamatic, Magnesium Taurate Powder , 8.8 oz (250 g)
Vitamatic, Magnesium Taurate Powder , 8.8 oz (250 g)
Vitamatic
200 mg25014.990.030View on iHerb →
5
Vitamatic, Chelated Magnesium, 180 Tablets (300 mg per Tablet)
Vitamatic, Chelated Magnesium, 180 Tablets (300 mg per Tablet)
Vitamatic
300 mg18019.990.037View on iHerb →
6
NutriBiotic, Immunity, Hypo-Aller C, Vitamin C with Calcium, Magnesium, Potassium & Zinc, 2.2 lb (1 kg)
NutriBiotic, Immunity, Hypo-Aller C, Vitamin C with Calcium, Magnesium, Potassium & Zinc, 2.2 lb (1 kg)
NutriBiotic
175 mg40030.300.043View on iHerb →
7
Rainbow Light, Magnesium Calcium+™, 90 Caplets
Rainbow Light, Magnesium Calcium+™, 90 Caplets
Rainbow Light
340 mg9014.870.049View on iHerb →
8
Swanson, Mellow Mag, Strawberry Kiwi, 19 oz (543 g)
Swanson, Mellow Mag, Strawberry Kiwi, 19 oz (543 g)
Swanson
330 mg11318.640.050View on iHerb →
9
Rainbow Light, Magnesium Calcium+™, 180 Caplets
Rainbow Light, Magnesium Calcium+™, 180 Caplets
Rainbow Light
340 mg18031.440.051View on iHerb →
10
Qunol, Magnesium, 120 Capsules (210 mg per Capsule)
Qunol, Magnesium, 120 Capsules (210 mg per Capsule)
Qunol
420 mg6015.000.060View on iHerb →
11
Amazing Nutrition, Daily Multivitamin, 250 Tablets
Amazing Nutrition, Daily Multivitamin, 250 Tablets
Amazing Nutrition
100 mg25014.990.060View on iHerb →
12
Source Naturals, Ultra-Mag™, 120 Tablets
Source Naturals, Ultra-Mag™, 120 Tablets
Source Naturals
420 mg6015.390.061View on iHerb →
13
Vitamatic, Magnesium Complex, 120 Capsules
Vitamatic, Magnesium Complex, 120 Capsules
Vitamatic
400 mg6014.990.063View on iHerb →
14
NOW Foods, Magnesium Bisglycinate Powder, 8 oz (227 g)
NOW Foods, Magnesium Bisglycinate Powder, 8 oz (227 g)
NOW Foods
300 mg7614.690.064View on iHerb →
15
NutriBiotic, Immunity, Hypo-Aller C, Vitamin C with Calcium, Magnesium, Potassium & Zinc, 8 oz (227 g)
NutriBiotic, Immunity, Hypo-Aller C, Vitamin C with Calcium, Magnesium, Potassium & Zinc, 8 oz (227 g)
NutriBiotic
175 mg9010.490.067View on iHerb →
16
NB Pure, MagO7, Cleanse, 180 Capsules
NB Pure, MagO7, Cleanse, 180 Capsules
NB Pure
1,035 mg6041.950.068View on iHerb →
17
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 200 Tablets
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 200 Tablets
Source Naturals
300 mg10024.330.081View on iHerb →
18
LifeTime Vitamins, Calcium-Magnesium, Potassium, Vitamin D & Boron, 120 Capsules
LifeTime Vitamins, Calcium-Magnesium, Potassium, Vitamin D & Boron, 120 Capsules
LifeTime Vitamins
500 mg3013.090.087View on iHerb →
19
Futurebiotics, Super Silica Complex™, 60 Vegetarian Tablets
Futurebiotics, Super Silica Complex™, 60 Vegetarian Tablets
Futurebiotics
150 mg607.970.089View on iHerb →
20
Bluebonnet Nutrition, Calcium Magnesium & Zinc, Bone Health, 180 Caplets
Bluebonnet Nutrition, Calcium Magnesium & Zinc, Bone Health, 180 Caplets
Bluebonnet Nutrition
400 mg6021.560.090View on iHerb →
21
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 100 Tablets
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 100 Tablets
Source Naturals
300 mg5013.650.091View on iHerb →
22
NaturesPlus, Cal/Mag with Whole Foods, 180 Tablets
NaturesPlus, Cal/Mag with Whole Foods, 180 Tablets
NaturesPlus
250 mg9020.780.092View on iHerb →
23
Swanson, Mellow Mag, Raspberry Lemonade, 19 oz (543 g)
Swanson, Mellow Mag, Raspberry Lemonade, 19 oz (543 g)
Swanson
330 mg11334.990.094View on iHerb →
24
Swanson, Mellow Mag, Orange, 20 oz (554 g)
Swanson, Mellow Mag, Orange, 20 oz (554 g)
Swanson
330 mg11336.310.097View on iHerb →
25
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 50 Tablets
Source Naturals, Sleep Science®, NightRest™ With Melatonin, 50 Tablets
Source Naturals
300 mg257.350.098View on iHerb →

How we rank Magnesium

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.