Product Image

Marine Based Cal-Mag 500/250 mg

Nature's Answer
4.7
★ ★ ★ ★ ★
(639 ratings)
Calcium 500 mg
Product Image
Score96

A high-quality marine mineral complex that provides bioavailable calcium and magnesium from red algae and seawater.

How scoring works
Quantity:120 Capsule(s) • (30 servings)
Goals:
Bone Health

Score 96

A high-quality marine mineral complex that provides bioavailable calcium and magnesium from red algae and seawater.

How scoring works
$27.74($0.92 per serving)
iHerb
$ 27.74
Pure Formulas
$ 28.27
Vitacost
$ 28.53
Report prices

Analysis

This formula relies on Aquamin, which is a mineral source derived from red algae and seawater. These plant-based and marine minerals are naturally structured in a way that helps the body absorb them more effectively than standard rock-based calcium.

The combination of calcium and magnesium in a 2:1 ratio is a traditional approach for maintaining bone density. It fits well for someone who wants a clean, nature-sourced mineral supplement without synthetic additives.

Pros

  • Uses plant-based Aquamin minerals
  • Includes seawater-derived magnesium
  • Balanced 2:1 mineral ratio
  • Higher bioavailability than basic salts

Cons

  • Lacks vitamin D3 for absorption
  • No vitamin K2 for mineral direction
  • Capsule count required per serving

Warnings

  • Take with food to assist digestion
  • Check total magnesium intake if using other supplements

Nutrient quality

99 Highest impact

Superior bioavailability of marine-based mineral forms provides a highly effective approach to bone health. Balanced 2:1 calcium to magnesium ratio ensures optimal synergy for skeletal mineralization.

Ingredient transparency

100 Highest impact

Labeling clearly identifies the Aquamin source and provides precise milligram yields for all minerals. Consumer confidence is bolstered by the transparent disclosure of the marine-based formula.

Customer satisfaction

96 Highest impact

Strong user ratings reflect high satisfaction with the product's natural source and efficacy. Feedback confirms the marine-based minerals are well-tolerated and perceived as superior to standard forms.

Value for money

87 Highest impact

Higher price point is justified by the use of premium, naturally structured marine mineral sources. Value is high for users seeking superior absorption and a whole-food mineral approach.

Report analysis

Goals

Bone Health
Impact
Highest effect
A Goal FitA Strength of SupportB- CoverageA Formula Quality

This mineral complex utilizes Aquamin red algae and seawater-derived minerals to provide a bioavailable source of calcium and magnesium. These marine-based forms are naturally structured to facilitate integration into human bone tissue.

The 2:1 ratio of calcium to magnesium provides a balanced approach to structural skeletal support. While the structural mineral supply is exceptional, the formula lacks signaling cofactors like vitamin D and K2 for optimal utilization.

View goal →

Ingredients

IngredientAmount per serving
Calcium (Aquamin Red Algae, Seawater)
 500 mg
Magnesium (Aquamin Seawater, Magnesium Hydroxide)
 250 mg
Sodium
15 mg
Gluten Free Adults 18–50 Vegan Vegetarian
Report overview
Calcium (Aquamin Red Algae, Seawater) · 500 mg OverallScore70
A+ Active Ingredient Quality & BioavailabilityC Dose, Safety & Label TransparencyF Value
This marine-based supplement utilizes Aquamin red algae and seawater-derived minerals for superior bioavailability. It provides a potent dose of calcium and magnesium in forms that are naturally structured for human absorption.
View ingredientView products
95 Value

Calcium Citrate Magnesium and Zinc

Kirkland Signature
4.7
★★★★★
(110 ratings)
Combining bioavailable calcium citrate with vitamin D3 and a wide array of cofactors like zinc and boron ensures multifaceted support for bone health. This formulation provides professional-grade mineral diversity in a format that offers excellent long-term value.
Other sellers (0)
96 Value

Calcium Citrate Caps

NOW
4.8
★★★★★
(2223 ratings)
Selection of the citrate form paired with chelated trace minerals like zinc and copper provides high bioavailability for building skeletal integrity. It offers a more complete mineral profile for mineral repletion at a very competitive price.
Other sellers (3)
98 Value

TriCalcium Complex with D & K

Swanson Premium Brand
4.8
★★★★★
(509 ratings)
Utilizing three distinct forms of calcium alongside vitamins D3 and K1 supports multiple absorption pathways for consistent mineral supply. This combination provides enhanced transport signaling at a very reasonable cost.
Other sellers (0)
96 Performance

Calcium Bone Maker Complex with MCH-Cal and VitaMK7

Doctor's Best
4.7
★★★★★
(7548 ratings)
Provision of microcrystalline hydroxyapatite provides a mineral structure that closely resembles natural human bone tissue for potentially better integration. The addition of vitamin K2 and boron supports the proper direction of calcium into the skeletal matrix.
Other sellers (4)
94 Performance

Ultra BoneUp

Jarrow Formulas
4.7
★★★★★
(594 ratings)
Incorporating microcrystalline hydroxyapatite alongside silicon and type II collagen offers a more comprehensive approach to skeletal resilience. This blend includes essential trace minerals and vitamins to support both the mineral and protein components of the bone.
Other sellers (4)
95 Performance

Cal/Mag 500 mg/250 mg

NaturesPlus
4.7
★★★★★
(671 ratings)
Utilization of calcium and magnesium amino acid chelates ensures high bioavailability and superior gastrointestinal comfort. These chelated forms are often more efficiently absorbed than the marine-derived hydroxides found in the original product.
Other sellers (1)
96 Budget

Calcium 500+D3

21st Century
4.8
★★★★★
(5261 ratings)
Providing 500 mg of elemental calcium from oyster shell alongside vitamin D3 offers a foundational approach to skeletal maintenance. This option delivers essential structural materials at a very economical price per serving.
Other sellers (2)
96 Budget

Calcium 500 mg with Vitamin D3

Nature's Bounty
4.8
★★★★★
(1238 ratings)
Selection of oyster shell calcium paired with cholecalciferol supports foundational bone density and mineralization goals. It provides a reliable source of primary minerals while remaining highly cost-effective for daily use.
Other sellers (1)
93 Budget

Chewable Calcium

Swanson Premium Brand
4.7
★★★★★
(293 ratings)
Delivering calcium carbonate and vitamin D3 in a chewable format provides a convenient and budget-friendly alternative for those who prefer not to swallow capsules. The formulation focuses on the essential components needed for skeletal support.
Other sellers (0)
95 Value

Calcium Citrate Magnesium and Zinc

Kirkland Signature
4.7
★★★★★
(110 ratings)
Combining bioavailable calcium citrate with vitamin D3 and a wide array of cofactors like zinc and boron ensures multifaceted support for bone health. This formulation provides professional-grade mineral diversity in a format that offers excellent long-term value.
Other sellers (0)
96 Value

Calcium Citrate Caps

NOW
4.8
★★★★★
(2223 ratings)
Selection of the citrate form paired with chelated trace minerals like zinc and copper provides high bioavailability for building skeletal integrity. It offers a more complete mineral profile for mineral repletion at a very competitive price.
Other sellers (3)
98 Value

TriCalcium Complex with D & K

Swanson Premium Brand
4.8
★★★★★
(509 ratings)
Utilizing three distinct forms of calcium alongside vitamins D3 and K1 supports multiple absorption pathways for consistent mineral supply. This combination provides enhanced transport signaling at a very reasonable cost.
Other sellers (0)
96 Performance

Calcium Bone Maker Complex with MCH-Cal and VitaMK7

Doctor's Best
4.7
★★★★★
(7548 ratings)
Provision of microcrystalline hydroxyapatite provides a mineral structure that closely resembles natural human bone tissue for potentially better integration. The addition of vitamin K2 and boron supports the proper direction of calcium into the skeletal matrix.
Other sellers (4)
94 Performance

Ultra BoneUp

Jarrow Formulas
4.7
★★★★★
(594 ratings)
Incorporating microcrystalline hydroxyapatite alongside silicon and type II collagen offers a more comprehensive approach to skeletal resilience. This blend includes essential trace minerals and vitamins to support both the mineral and protein components of the bone.
Other sellers (4)
95 Performance

Cal/Mag 500 mg/250 mg

NaturesPlus
4.7
★★★★★
(671 ratings)
Utilization of calcium and magnesium amino acid chelates ensures high bioavailability and superior gastrointestinal comfort. These chelated forms are often more efficiently absorbed than the marine-derived hydroxides found in the original product.
Other sellers (1)
Report alternatives