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Phosphate salts

What is it?

Phosphate salts refers to many different combinations of the chemical phosphate with salts and minerals. Foods high in phosphate include dairy products, whole grain cereals, nuts, and certain meats. Phosphates found in dairy products and meats seem to be more easily absorbed by the body than phosphates found in cereal grains. Cola drinks contain a lot of phosphate - so much, in fact, that they can cause too much phosphate in the blood.

People use phosphate salts for medicine. Be careful not to confuse phosphate salts with substances such as organophosphates, or with tribasic sodium phosphates and tribasic potassium phosphates, which are very poisonous.

Phosphate salts are taken by mouth for treating blood phosphate levels that are too low and blood calcium levels that are too high, and for preventing kidney stones. They are also taken for treating osteomalacia (often called “rickets” in children), a condition caused by a mineral imbalance in the body that leads to softening of the bones. Phosphate salts are also used for improving exercise performance, as an antacid for gastroesophageal reflux disease (GERD), and as a laxative for emptying the bowels before surgery.

Phosphate salts and calcium are applied to sensitive teeth to reduce pain.

Rectally, phosphate salts are used as a laxative to clean the bowels before surgery or intestinal tests.

Healthcare providers sometimes give potassium phosphate intravenously (by IV) for treating low phosphate and high calcium levels in the blood, and for preventing low phosphate in patients who are being tube-fed.

How effective is it?

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for PHOSPHATE SALTS are as follows:

Effective for...

  • Correcting low blood phosphate levels, when sodium and potassium phosphates are taken by mouth or given intravenously (by IV) by a healthcare provider.

Likely effective for...

  • Correcting high blood calcium levels, when sodium and potassium phosphates are used.

Possibly effective for...

  • Preventing some types of kidney stones.

Likely ineffective for...

  • Improving aerobic exercise performance.

Insufficient evidence to rate effectiveness for...

  • Sensitive teeth.
  • Heartburn.
  • Cleaning out the bowels as a laxative preparation for intestinal tests such as colonoscopy when sodium phosphates are used.
  • Other conditions.
More evidence is needed to rate the effectiveness of phosphate salts for these uses.

How does it work?

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Phosphates are normally absorbed from food and are important chemicals in the body. They are involved in cell structure, energy transport and storage, vitamin function, and numerous other processes essential to health. Phosphate salts can act as laxatives by causing more fluid to be drawn into the intestines and stimulating the gut to push out its contents faster.

Are there safety concerns?

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Phosphate salts containing sodium, potassium, aluminum, or calcium seem to be safe for most people when used occasionally or short-term. Phosphate intake (expressed as phosphorus) should not be more than 4 grams per day for adults younger than 70 years of age and 3 grams per day for people who are older.

Regular long-term use can upset the balance of phosphates and other chemicals in the body and should be monitored by a healthcare professional to avoid serious side effects. Phosphate salts can irritate the digestive tract and cause stomach upset, diarrhea, constipation, and other problems.

Do not confuse phosphate salts with substances such as organophosphates, or with tribasic sodium phosphates and tribasic potassium phosphates, which are very poisonous.

Special precautions & warnings:

Pregnancy and breast-feeding: Phosphate salts from dietary sources are LIKELY SAFE for pregnant or breast-feeding women when used at the recommended allowances of 1250 mg daily for mothers between 14-18 years of age and 700 mg daily for those over 18 years of age. Other amounts should only be used with the advice and ongoing care of a healthcare professional.

Children: Phosphate salts are LIKELY SAFE for children when used at the recommended daily allowances of 460 mg for children 1-3 years of age; 500 mg for children 4-8 years of age; and 1250 mg for children 9-18 years of age. Phosphate salts can be UNSAFE if phosphate consumed (expressed as phosphorous) exceeds the tolerable upper intake level (UL). The ULs are 3 grams per day for children 1-8 years; and 4 grams per day for children 9 years and older.

Heart disease: Avoid using phosphate salts that contain sodium if you have heart disease.

Fluid retention (edema): Avoid using phosphate salts that contain sodium if you have cirrhosis, heart failure, or other conditions that can cause edema.

High levels of calcium in the blood (hypercalcemia): Use phosphate salts cautiously if you have hypercalcemia. Too much phosphate could cause calcium to be deposited where it shouldn’t be in your body.

High levels of phosphate in the blood: People with Addison's disease, severe heart and lung disease, kidney disease, thyroid problems, or liver disease are more likely than other people to develop too much phosphate in their blood when they take phosphate salts. Use phosphate salts only with the advice and ongoing care of a healthcare professional if you have one of these conditions.

Kidney disease: Use phosphate salts only with the advice and ongoing care of a healthcare professional if you have kidney problems.

Are there interactions with medications?

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Be cautious with this combination.

Bisphosphonate medications and phosphate salts can both lower calcium levels in the body. Taking large amounts of phosphate salts might cause calcium levels to become too low.

Some bisphosphonates include alendronate (Fosamax), etidronate (Didronel), risedronate (Actonel), tiludronate (Skelid), and others.

Are there interactions with herbs and supplements?

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Calcium, iron, and magnesium
Phosphate can combine with calcium, iron, or magnesium. This reduces the body's ability to absorb phosphate, calcium, iron, and magnesium. To avoid this interaction, phosphate should be taken at least 2 hours before or after taking calcium, iron, or magnesium.

Are there interactions with foods?

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There are no known interactions with foods.

What dose is used?

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The following doses have been studied in scientific research:

  • For raising phosphate levels that are too low or lowering calcium levels that are too high: Healthcare providers measure the levels of phosphate and calcium in the blood and give just enough phosphate to correct the problem.
As a supplement, the recommended daily dietary allowances (RDAs) of phosphate (expressed as phosphorus) are: Children 1-3 years, 460 mg; children 4-8 years, 500 mg; men and women 9-18 years, 1250 mg; men and women over 18 years, 700 mg.

The adequate intakes (AI) for infants are: 100 mg for infants 0-6 months old and 275 mg for infants 7-12 months of age.

Tolerable Upper Intake Levels (UL), the highest intake level at which no unwanted side effects are expected, for phosphate (expressed as phosphorus) per day are: children 1-8 years, 3 grams per day; children and adults 9-70 years, 4 grams; adults older than 70 years, 3 grams; pregnant women 14-50 years, 3.5 grams; and breast-feeding women 14-50 years, 4 grams.

Other names

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Aluminum phosphate, Bone Phosphate, Calcium phosphate, Calcium Orthophosphate, Calcium Phosphate Dibasic Anhydrous, Calcium Phosphate-Bone Ash, Calcium Phosphate Dibasic Dihydrate, Calcium Phosphate Dibasique Anhydre, Calcium Phosphate Dibasique Dihydrate, Calcium Phosphate Tribasic, Calcium Phosphate Tribasique, Dibasic Calcium Phosphate Dihydrate, Di-Calcium Phosphate, Dicalcium Phosphate, Dicalcium Phosphates, Neutral Calcium Phosphate, Orthophosphate de Calcium, Phosphate d’Aluminium, Phosphate de Calcium, Phosphate de Magnésium, Phosphate Neutre de Calcium, Phosphate d’Os, Phosphate Tricalcium, Precipitated Calcium Phosphate, Précipitation du Phosphate de Calcium, Précipité de Phosphate de Calcium, Tertiary Calcium Phosphate, Tricalcium Phosphate, Whitlockite, Magnesium Phosphate, Merisier, Potassium phosphate, Dibasic Potassium Phosphate, Dipotassium Hydrogen Orthophosphate, Dipotassium Monophosphate, Dipotassium Phosphate, Monobasic Potassium Phosphate, Potassium Acid Phosphate, Potassium Biphosphate, Potassium Dihydrogen Orthophosphate, Potassium Hydrogen Phosphate, Phosphate de Dipotassium, Phosphate d’Hydrogène de Potassium, Phosphate de Potassium, Phosphate de Potassium Dibasique, Phosphate de Potassium Monobasique, Sodium phosphate, Anhydrous Sodium Phosphate, Dibasic Sodium Phosphate, Disodium Hydrogen Orthophosphate, Disodium Hydrogen Orthophosphate Dodecahydrate, Disodium Hydrogen Phosphate, Disodium Phosphate, Phosphate of Soda, Sales de Fosfato, Sels de Phosphate, Sodium Orthophosphate, Orthophosphate Disodique d’Hydrogène, Phosphate Disodique d’Hydrogène, Orthophosphate de Sodium, Phosphate de Sodium Anhydre, Phosphate de Sodium Dibasique.


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To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.methodology (


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Last reviewed - 08/22/2012

Page last updated: 08 September 2014