Obligate Co-factor
Magnesium
Magnesium is required by the hydroxylase enzymes that convert vitamin D into its active forms.
What it is
Who it suits
General wellness support
Best price today
$18.40 at iHerb ()
Verified clinical advantages
Trade-offs & compromises
Multi-store price comparison
| Merchant | Base price | Shipping | Delivery | Stock | |
|---|---|---|---|---|---|
| iHerb | $18.40 | Free | In stock | View on iHerb |
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Disclosure: We are an independent comparison platform. We may earn an affiliate commission when you purchase through links on our site at no extra cost to you. As an Amazon Associate, we earn from qualifying purchases. Buttons take you to the named retailer's own site to complete your purchase.
Similar alternatives
Same category, different carrier economics.
Solgar
Advanced Calcium Complex + Vitamins D3 K2 Zinc Boron
—
$23.89· $0.80 cost per serving
- 1631% dearer cost per serving
- Fewer servings per pack (30 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Swanson Vitamins
Albion® Magnesium & Calcium with Vitamins D3 & K2
—
$16.82· $0.19 cost per serving
- 306% dearer cost per serving
- Fewer servings per pack (90 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Nature's Way
Alive!® Calcium & Vitamin D3 Gummy Raspberry-Lemonade & Strawberry
—
$17.00· $0.28 cost per serving
- 516% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Ddrops
Baby Organic Liquid Vitamin D3 10 mcg (400 IU) 90 Drops 0.08 fl oz (2.5 ml)
—
$22.23
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
California Gold Nutrition
Baby Vitamin D3 Drops 10 mcg (400 IU) 0.34 fl oz (10 ml)
—
$8.42
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
California Gold Nutrition
Baby's DHA Omega-3s with Vitamin D3 and EPA 2 fl oz (59 ml)
—
$17.25
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NaturesPlus
Cal/Mag/Vit D3 with Vitamin K2,180 Tablets
—
$35.40· $0.79 cost per serving
- 1610% dearer cost per serving
- Fewer servings per pack (45 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Calcium & Magnesium With Vitamin D-3 and Zinc
—
$29.37· $0.37 cost per serving
- 698% dearer cost per serving
- Fewer servings per pack (80 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Calcium & Magnesium with Vitamin D3 and Zinc
—
$16.75· $0.42 cost per serving
- 810% dearer cost per serving
- Fewer servings per pack (40 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
GummiKing
Calcium + Vitamin D Gummies For Kids
—
$11.38· $0.38 cost per serving
- 725% dearer cost per serving
- Fewer servings per pack (30 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Solaray
Calcium Bisglycinate with Vitamin D-3,120 VegCaps
—
$17.27
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
Calcium Citrate + D3 Maximum
—
$11.20· $0.19 cost per serving
- 306% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
Calcium Citrate Petites + D3,200 Coated Tablets
—
$13.68· $0.14 cost per serving
- 197% dearer cost per serving
- Fewer servings per pack (100 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Life Extension
Calcium Citrate with Vitamin D
—
$22.51· $0.11 cost per serving
- 145% dearer cost per serving
- Fewer servings per pack (200 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Solgar
Calcium Citrate with Vitamin D3,240 Tablets
—
$28.49· $0.47 cost per serving
- 932% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
Calcium Magnesium Zinc + D3
—
$6.42· $0.21 cost per serving
- 365% dearer cost per serving
- Fewer servings per pack (30 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
Calcium Magnesium Zinc + D3,250 Tablets
—
$15.55· $0.19 cost per serving
- 307% dearer cost per serving
- Fewer servings per pack (83 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Nature's Bounty
Calcium Magnesium Zinc with Vitamin D3,100 Coated Caplets
—
$9.51· $0.29 cost per serving
- 526% dearer cost per serving
- Fewer servings per pack (33 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
Calcium Plus D3
—
$9.02· $0.10 cost per serving
- 118% dearer cost per serving
- Fewer servings per pack (90 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Citracal
Calcium Supplement + D3 Slow Release 1200 80 Coated Tablets
—
$20.10· $0.50 cost per serving
- 992% dearer cost per serving
- Fewer servings per pack (40 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Citracal
Calcium Supplement +D3 Petites 200 Coated Caplets
—
$20.41
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Chewable Vitamin D-3 Fruit 25 mcg (1,000 IU) 180 Chewables
—
$9.62
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
California Gold Nutrition
Chewable Vitamin D3 for Children Natural Cherry 12.5 mcg (500 IU) 90 Vegetarian Tablets
—
$9.67· $0.11 cost per serving
- 134% dearer cost per serving
- Fewer servings per pack (90 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
21st Century
D3
—
$3.52· $0.06 cost per serving
- 28% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Sports Research
D3 + K2 Plant-Based 120 Veggie Softgels
—
$62.25· $0.52 cost per serving
- 1028% dearer cost per serving
- Fewer servings per pack (120 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Sports Research
D3 + K2 Plant-Based 125 mcg/100 mcg 60 Veggie Softgels
—
$36.01· $0.60 cost per serving
- 1205% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Sports Research
D3 + K2 Plant-Based 250 mcg/100 mcg 60 Veggie Softgels
—
$37.41· $0.62 cost per serving
- 1255% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Sports Research
D3 + K2 Plant-Based 30 Veggie Softgels
—
$26.39· $0.88 cost per serving
- 1812% dearer cost per serving
- Fewer servings per pack (30 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Sports Research
D3 + K2 Plant-Based 62.5 mcg/100 mcg 60 Veggie Softgels
—
$31.91· $0.53 cost per serving
- 1056% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Michael's Health
D3 with Vitamin K2 Apricot 90 Vegetarian Chewable Tablets
—
$24.98
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Vitacost
Everyday Essentials Ultra Calcium With Vitamin D3,120 Softgels
—
$10.33· $0.17 cost per serving
- 274% dearer cost per serving
- Fewer servings per pack (60 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Vitacost
Everyday Essentials Vitamin D3 & K2 Natural Cherry 60 Chewable Tablets
—
$3.78
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Vitacost
Everyday Essentials Vitamin D3 Mini Gels 50 mcg (2,000 IU)
—
$3.66· $0.03 cost per serving
- 34% cheaper cost per serving
- Fewer servings per pack (120 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Trace
Ionic D3 + K2 2 fl oz (59 ml)
—
$36.51· $0.12 cost per serving
- 168% dearer cost per serving
- Fewer servings per pack (296 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Zahler
Junior D3 & K2 Peach Apricot 90 Chewable Tablets
—
$20.07· $0.22 cost per serving
- 385% dearer cost per serving
- Fewer servings per pack (90 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Carlson
Kid's Super Daily® D3 + K2 0.34 fl oz (10.16 ml)
—
$26.08· $0.07 cost per serving
- 57% dearer cost per serving
- Fewer servings per pack (360 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Carlson
Kid's Vitamin D3 Gummies Natural Fruit 25 mcg (1,000 IU) 60 Vegetarian Gummies
—
$13.95· $4.65 cost per serving
- 10004% dearer cost per serving
- Fewer servings per pack (3 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Ddrops
Kids Booster Organic Liquid Vitamin D3 15 mcg (600 IU) 0.09 fl oz (2.8 ml)
—
$17.91· $0.18 cost per serving
- 289% dearer cost per serving
- Fewer servings per pack (100 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Lifeable
Kids Calcium Magnesium & Zinc + Vitamin D3 Gummies Raspberry
—
$20.60· $6.87 cost per serving
- 14824% dearer cost per serving
- Fewer servings per pack (3 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
California Gold Nutrition
Kids Liquid Calcium with Magnesium Vitamin D and Zinc Orange 16 fl oz (473 ml)
—
$21.85· $0.46 cost per serving
- 910% dearer cost per serving
- Fewer servings per pack (47 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Lifeable
Kids Vitamin D3 + K2 Gummies Strawberry
—
$20.13· $10.07 cost per serving
- 21778% dearer cost per serving
- Fewer servings per pack (2 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Nature's Craft
Kids Vitamin D3 + K2 Organic Drops 60 ml
—
$22.20· $0.18 cost per serving
- 302% dearer cost per serving
- Fewer servings per pack (120 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
Solgar
Liquid Calcium Magnesium Citrate with Vitamin D3 Strawberry 16 fl oz (473 ml)
—
$18.21
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
ChildLife Clinicals
Liquid Calcium/Magnesium Formula with Vitamin D3 & Vitamin K2 Natural Orange 16 fl oz (473 ml)
—
$42.40
- Comparable specification to this product.
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Liquid D3 & MK-7 Natural Mint 1 fl oz (30 ml)
—
$23.62· $0.14 cost per serving
- 215% dearer cost per serving
- Fewer servings per pack (163 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Liquid Vitamin D-3 1,000 IU 1 fl oz (30 ml)
—
$11.28· $0.02 cost per serving
- 67% cheaper cost per serving
- More servings per pack (750 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Liquid Vitamin D-3 2 fl oz (59 ml)
—
$8.66· $0.02 cost per serving
- 64% cheaper cost per serving
- More servings per pack (527 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.
NOW Foods
Magnesium & Calcium With Zinc and Vitamin D-3,100 Tablets
—
$16.71· $0.51 cost per serving
- 1000% dearer cost per serving
- Fewer servings per pack (33 vs 400)
Approximate conversion — the retailer charges in EUR.
Prices last synced: 3 Oct 2026, 18:04 UTC. Prices and availability are subject to change.