Coral Calcium Powder (Okinawa)



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*(Documents above may vary from batch received. Click here to request batch-specific documents)

Supplement Facts & Directions

Supplement Facts

Serving Size: 1300 milligrams
Servings Per Container: Varies
Amount Per Serving % Daily Value*
Calcium (from Coral Calcium) 551 mg 55%

* Percent Daily Values are based on a 2,000 calorie diet.
† Daily Value Not Established
‡ These supplement facts may vary from the product you receive. Please call for exact numbers.

Other Ingredients: None


Free of: Added Sugar, Soy, Dairy, Yeast, Gluten, Corn & Additives.

Directions: As a dietary supplement, take 1300 mg (1/4 tsp) up to twice daily or as directed by a physician.

Warning: If you are pregnant, nursing, taking any medications, or have any medical conditions consult your physician before use. Keep out of reach of children.

WARNING: Consuming this product can expose you to chemicals including lead which is known to the State of California to cause birth defects or other reproductive harm. For more information, go to

Product Details

Calcium is the fifth most abundant element and the third most abundant metal found in the earth’s crust. The name calcium comes from the Latin word calx, meaning lime, and it is a direct reference to one of the more common calcium sources: limestone. It is an essential mineral that is vital to life and is the building block for bones (including teeth). Calcium also plays a pivotal role in cell signaling and mitochondrial function.

What is Coral Calcium (Aragonite)?

Coral calcium is a calcium salt derived from fossilized coral reefs. Like other calcium sources such as oyster shells or limestone rock, it’s primarily calcium carbonate (CaCO3) with trace amounts of magnesium and many other minerals. Calcium carbonate is one of the most prevalent calcium compounds, and it has anti-inflammatory and antioxidant properties. Calcium carbonate has three crystal forms: calcite, vaterite, and aragonite. Almost all members of the Mollusca phylum contain aragonite, and it forms the exoskeleton of corals. Aragonite is critical for replicating reef conditions and sustaining most sea life. It helps aquaria sustain its natural pH, and it is an effective means of removing contaminants from polluted water.

PureBulk’s coral calcium originates from Okinawa, Japan. The Japanese government carefully controls the sale of coral calcium to protect living coral reefs.

Potential Calcium Benefits

Calcium for Bones

Calcium plays a pivotal role in forming and maintaining strong bones, as evidenced by the robust bone health in individuals that consume calcium-rich diets. Coral calcium rose in popularity in part because of Okinawans’ long lifespans. A proposed explanation is the mineral content in their water due to the prevalence of coral reefs. Coral calcium has a similar composition to human bones, and surgeons have used it as a bone graft material for more than three decades.

It also contains hydroxyapatite, a calcium product that comprises up to 70% of human bones by weight and 80% of dentin and enamel mass in teeth. It also helps counteract dental hypersensitivity associated with teeth whitening products and protects against cavity formation. Dental surgeons use hydroxyapatite for hard tissue repairs, as it bears a strong chemical similarity to natural hard tissues like enamel and dentin. A human study noted that coral calcium is easier to absorb than standard calcium supplements. An animal study also reported that coral calcium improved bone mineral density better than regular calcium supplements.

Calcium and Vitamin D

Vitamin D is critical for optimal calcium absorption. The human body needs adequate vitamin D to form calcitriol (active vitamin D). Without sufficient calcitriol, the body can’ absorb calcium from dietary sources.

Calcium Carbonate Antacid Properties

Calcium carbonate is an effective stomach acid neutralizer. As such, many individuals take it to relieve upset stomach, acid indigestion, and heartburn. Excess stomach acid erodes the mucus membrane that lines the stomach, causing stomach pain. It also increases the likelihood of acid reflux, which can cause heartburn and wear away at the teeth.

Calcium and Heart Health

Calcium supplements may support heart health in a few ways. Milk products fortified with calcium reduce lipid absorption by improving how well the body excretes fats. One study noted an increased excretion rate of total fat by 139% and fatty acids by 195%. An animal study also reported that coral calcium exerted anti-inflammatory and antihypertensive effects on vascular cells.

Calcium Deficiency Symptoms

Vitamin D deficiencies are the most common cause of hypocalcemia (low calcium). However, postmenopausal women, individuals with milk allergies, individuals with lactose intolerance, and vegans have an increased risk of developing a calcium deficiency. Symptoms include weak or brittle bones, increased falling, tingling in the hands and feet, numbness around the mouth, and muscle spasms.

Potential Calcium Side Effects

Calcium supplements don’t typically cause side effects. Individuals may experience minor gastrointestinal side effects while taking calcium supplements, such as bloating, constipation, or gas. However, taking large doses on a consistent basis can lead to hypercalcemia (high calcium blood levels) and other health problems. Consult with a physician before taking any new supplements.


Tested by Accredited 3rd Party Labs

PureBulk's supplements are tested by accredited third party labs in the USA to ensure their identity, purity and potency. To receive a copy of these test results or any other PureBulk supplement please fill out the COA request form found here.

*NOTE: These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.

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