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Dicalcium phosphate

Dicalcium phosphate suppliers and sourcing guide

Dicalcium phosphate is calcium hydrogen phosphate (CaHPO4), sold as the anhydrous salt or the dihydrate. It is made by reacting purified phosphoric acid with lime or calcium carbonate under controlled pH, then filtering, drying and milling or granulating. It is a dense, white, insoluble powder. Brands buy it as a direct-compression filler for tablets, as a source of calcium and phosphorus in fortified foods and supplements, and as a leavening acid component and anticaking agent.

Also known as
Calcium phosphate, dibasic · Calcium hydrogen phosphate · Dibasic calcium phosphate · DCP · E341(ii)
Facts checked
November 2026

Forms and grades of dicalcium phosphate

Suppliers sell different products under the same name. Specify the one you need.

  • Dihydrate

    CaHPO4·2H2O, a common tablet filler; it can lose its water of hydration above about 40 to 50°C.

  • Anhydrous

    CaHPO4 without bound water, used with moisture-sensitive actives and at higher process temperatures.

  • Granular direct-compression grades

    Coarser, free-flowing granules for direct compression tablets.

  • Fine powder grades

    Milled powders for food fortification, toothpaste and wet granulation.

What to check on the COA

Compare each result with your own specification when the lot arrives.

Assay
CaHPO4 content by complexometric (EDTA) titration of calcium.
Loss on ignition
Distinguishes dihydrate from anhydrous material and confirms hydration state.
Fluoride
Fluoride by ion-selective electrode, a carryover from phosphate rock, against the FCC or pharmacopeial limit.
Heavy metals
Lead, arsenic and cadmium by ICP-MS, since phosphate raw materials can carry metals.
Particle size and bulk density
Sieve analysis and bulk density, which set flow and tablet fill.
Acid-insoluble substances and carbonate
Pharmacopeial purity tests for insoluble matter and residual carbonate.

Storage, lots and expiry

Storage and shelf life

Store sealed in a dry place at room temperature. The dihydrate should not be stored hot, since it can lose water and change behavior in tablets. Shelf life or retest date comes from the supplier; anhydrous and dihydrate material is usually stable for years, with assay and loss on ignition rechecked.

Lots and expiry dates

Hydration state, particle size and fluoride or metals results can vary by lot and source rock. Record the form, loss on ignition and metal results per lot, and do not interchange dihydrate and anhydrous grades without testing.

Regulatory status

Facts from regulators and standards bodies, each linked to its source.

  • 21 CFR 182.1217 lists calcium phosphate (mono-, di-, and tribasic) as generally recognized as safe when used in accordance with good manufacturing practice.

    Source: ecfr.gov (opens in a new tab)
  • 7 CFR 205.605 lists calcium phosphates (monobasic, dibasic, and tribasic) among the synthetic substances allowed as ingredients in or on processed products labeled "organic" or "made with organic (specified ingredients or food group(s))".

    Source: ecfr.gov (opens in a new tab)
  • Health Canada's Natural Health Products Ingredients Database lists dibasic calcium phosphate (common names include dicalcium phosphate) with non-medicinal purposes including binder, diluent, direct compression excipient and filler.

    Source: webprod.hc-sc.gc.ca (opens in a new tab)

This is general information, not regulatory advice. Status differs by country and by how the ingredient is used, so check the rules for your product and market.

Dicalcium phosphate suppliers

Manufacturers and distributors whose own websites say they sell it.

  • Innophos

    Manufacturer · Cranbury, NJ

    Sells it as A-Tab

    US manufacturer of food, pharmaceutical and technical grade phosphates, including phosphoric acid, sodium and calcium phosphates, leavening acids and polyphosphates.

Suppliers are in alphabetical order and none pays to appear. Each claim is checked against the supplier’s own website on the date shown. Ask for the specification sheet and a recent COA before you order, and confirm details with the supplier.

Frequently asked questions

What forms of dicalcium phosphate can brands buy?

Common forms include dihydrate, anhydrous, granular direct-compression grades and fine powder grades. Ask each supplier for the specification sheet of the exact grade they quote.

What should the COA for dicalcium phosphate include?

Expect assay, loss on ignition, fluoride, heavy metals, particle size and bulk density and acid-insoluble substances and carbonate, each with its method, specification and result for that lot.

How should dicalcium phosphate be stored?

Store sealed in a dry place at room temperature. The dihydrate should not be stored hot, since it can lose water and change behavior in tablets. Shelf life or retest date comes from the supplier; anhydrous and dihydrate material is usually stable for years, with assay and loss on ignition rechecked.

What is the regulatory status of dicalcium phosphate?

21 CFR 182.1217 lists calcium phosphate (mono-, di-, and tribasic) as generally recognized as safe when used in accordance with good manufacturing practice. 7 CFR 205.605 lists calcium phosphates (monobasic, dibasic, and tribasic) among the synthetic substances allowed as ingredients in or on processed products labeled "organic" or "made with organic (specified ingredients or food group(s))". Health Canada's Natural Health Products Ingredients Database lists dibasic calcium phosphate (common names include dicalcium phosphate) with non-medicinal purposes including binder, diluent, direct compression excipient and filler.

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