Understanding Which Mineral Makes Up About 40% of the Body's Mineral Mass

December 29, 2025 •

2 min read

While calcium is the single most abundant mineral in the body, its relationship with another mineral is key to the 40% figure. This substantial proportion is found within the bones, where calcium combines with phosphorus to form the durable structure of our skeleton.

Quick Summary

The majority of the body's mineral mass is composed of the mineral component of bone, which consists of calcium and phosphorus crystallized into hydroxyapatite. Calcium is the most prevalent mineral overall, with almost 99% stored in the bones and teeth.

Key Points

The Mineral Combination: The 40% figure refers to the mineral component of bone, which is a calcium phosphate crystal called hydroxyapatite.
Calcium is Most Abundant: Calcium is the single most abundant mineral, but it acts in concert with phosphorus to form the structure of bone.
Skeletal Storage: Over 99% of the body's total mineral mass is stored within the skeleton.
Beyond Bone Structure: Both calcium and phosphorus are crucial for other bodily functions, including nerve transmission, muscle contraction, and energy production.
Dietary Importance: Consistent intake of both calcium and phosphorus through diet, alongside sufficient vitamin D, is essential for maintaining proper mineral balance.
Homeostatic Control: The body will draw calcium from the bones to maintain blood levels, which can lead to weakened bones over time if dietary intake is low.

The Abundant Duo: Calcium and Phosphorus

Approximately 99% of the minerals in the human body are stored in the bones and teeth. When discussing the body's mineral mass, the composition of the skeleton is key. The question of which mineral makes up about 40% of the body's mineral mass refers to the mineral component within bone, known as hydroxyapatite. This is a calcium phosphate crystal, not a single element.

Calcium is the most abundant single mineral, making up 1.5 to 2% of adult body weight. The mineral part of bone (hydroxyapatite) constitutes nearly 40% of bone's total weight. This 40% figure thus relates to the bone mineral composition. The combination of calcium and phosphorus provides structural strength.

The Critical Role of Calcium

Calcium is vital for numerous bodily functions beyond bone health. The body can take calcium from the skeleton if dietary intake is insufficient, potentially weakening bones over time.

Skeletal Support: Forms the structure of bones and teeth.
Muscle Function: Aids muscle contraction and relaxation.
Nerve Transmission: Helps send nerve signals.
Blood Clotting: Essential for coagulation.
Cellular Signaling: Acts as an intracellular messenger.

The Importance of Phosphorus

Phosphorus is the body's second most abundant mineral and a major bone component. It works with calcium in forming hydroxyapatite; phosphorus is laid down first, then calcium binds to it.

Bone and Teeth Formation: A key part of hydroxyapatite structure.
Energy Production: Part of ATP, the body's energy molecule.
DNA and RNA: Essential for genetic material.
Cellular Membranes: Forms phospholipids in cell membranes.
pH Balance: Helps regulate acid-base balance.

Comparison of Calcium and Phosphorus


Feature	Calcium	Phosphorus
Abundance	Most abundant mineral.	Second most abundant mineral.
Primary Role in Bone	Provides hardness and structure in hydroxyapatite.	Forms the phosphate backbone of hydroxyapatite.
Dietary Sources	Dairy, leafy greens, fortified foods.	Dairy, meat, fish, nuts, legumes.
Absorption Aid	Requires Vitamin D.	Requires Vitamin D.
Non-Skeletal Functions	Muscle, nerve, blood clotting.	Energy, genetic material.

Addressing the Source of the 40% Figure

The 40% figure refers to the mineral part of bone, primarily hydroxyapatite, which constitutes nearly 40% of bone's weight. Since bones hold over 99% of the body's mineral mass, this figure represents the bulk of the body's total mineral content. The answer is the combined presence of calcium and phosphorus within the bone's mineral matrix. Maintaining skeletal health requires adequate intake of both minerals, plus vitamin D.

Conclusion

While calcium is the most abundant individual mineral, the approximately 40% figure for the body's mineral mass refers to the mineral compound of bone, hydroxyapatite, which is composed of both calcium and phosphorus. This compound gives the skeleton its rigidity. Supporting this requires a diet rich in calcium and phosphorus, and adequate vitamin D for absorption. This combination is essential for skeletal health and other vital bodily functions.

Resources

National Institutes of Health (NIH), Office of Dietary Supplements: Calcium Fact Sheet for Health Professionals

Frequently Asked Questions

Hydroxyapatite is a crystalline compound primarily made of calcium and phosphorus that forms the hard, mineralized part of bones and teeth.

The vast majority of the body's mineral mass, more than 99%, is stored in the skeleton, providing the body with its structural framework.

If dietary calcium intake is low, the body will take calcium from the bones to maintain its blood levels, which can lead to weakened bones and a higher risk of osteoporosis over time.

Vitamin D is essential for the proper absorption of calcium in the gut, making it a critical component for maintaining healthy bones and teeth.

While calcium and phosphorus are the primary minerals, other trace minerals like magnesium also play a supporting role in bone formation and health.

Excellent dietary sources of calcium include dairy products, leafy green vegetables like kale and broccoli, and fortified foods such as cereals and plant-based milks.

Yes, excessive intake of calcium, often from high doses of supplements, can lead to side effects such as kidney stones and other health risks, especially in people with pre-existing conditions.