# Coral calcium

Source: https://onco.cc/technologies/coral-calcium/  
OnCo record `coral-calcium` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Coral calcium was advertised as a cure for cancer and as the secret of long life in Okinawa. There is no evidence it has anticancer effects, the US Federal Trade Commission has banned such claims, and one product tested contained too much lead. As a calcium source it behaves like other calcium supplements but costs more.

## Summary

Coral calcium is harvested from eroded coral and sold as a calcium supplement and longevity product. Memorial Sloan Kettering's About Herbs entry states there is no evidence that coral calcium has anticancer properties, that claims it maintains the body's pH balance are unsubstantiated, and that Okinawan longevity is more plausibly explained by the traditional plant-based diet. The US Federal Trade Commission has prohibited marketers from making disease treatment and cure claims, and an independent laboratory found excessive lead in one product. Limited studies suggest its calcium may be well absorbed, and in a rodent model of postmenopausal bone loss it performed like calcium carbonate. It has no adverse effects beyond those of other calcium supplements, which include kidney stones and high blood calcium; people with high calcium or low phosphate levels, which can occur with some cancers, should consult their doctor first. Oral coral calcium should not be confused with the coral matrix used in bone grafting.

## Fields

- Kind: Technology
- Status: negative
- Last checked: 2026-11-04
- Also known as: Okinawa coral calcium; Coral calcium hydride
- Tags: complementary; supportive-care; evidence:insufficient
- Principle: Calcium carbonate with magnesium in a natural ratio; the 'alkalising' rationale for cancer has no scientific basis.
- Strengths: Works as an ordinary calcium source
- Limitations: No evidence of anticancer effect; FTC banned cure claims; Lead contamination found in one product; Costs more than equivalent calcium

## Sources

- MSK About Herbs: Coral calcium (page last updated 5 January 2022): https://www.mskcc.org/cancer-care/integrative-medicine/herbs/coral-calcium

## Connected records

- technologies: [Alternative medicine used instead of standard treatment](https://onco.cc/technologies/alternative-medicine-instead-of-treatment/), [Calcium supplements during and after cancer treatment](https://onco.cc/technologies/calcium-supplements/), [Evidence-based integrative oncology](https://onco.cc/technologies/integrative-oncology/), [Germanium supplements (Ge-132, 'vitamin O')](https://onco.cc/technologies/germanium-supplements/)
- fronts: [Supportive Care & Survivorship](https://onco.cc/fronts/supportive-care/)
- terms: [Unproven diet claims (alkaline, juice, 'anti-cancer' diets)](https://onco.cc/terms/unproven-diet-claims/)
- bottlenecks: [Misinformation and unproven therapies](https://onco.cc/bottlenecks/b-misinformation/)

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