Sodium Hexametaphosphate

Common names: Graham’s Salt, Glassy Sodium, Calgon (brand name), SHMP (abbreviation), E452i (European food additive code for Sodium Hexametaphosphate).

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KIDSADVISORY SAFETY RATING

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Caution

Published by Jordana Tobelem, RD, LDN — Last Updated on Apr 1, 2025

Medically reviewed by Dr. William Lin, MD

Sodium hexametaphosphate (SHMP) is a multifunctional food additive widely utilized for its sequestrant, emulsifying, and texturizing properties. It effectively binds metal ions, preventing discoloration and stabilizing the texture of processed foods. Common applications include its use in processed meats, dairy products, and carbonated beverages to enhance quality and extend shelf life.^[1]
While SHMP is generally recognized as safe (GRAS) by regulatory agencies, excessive intake of phosphate additives has been associated with potential health risks, such as cardiovascular issues, particularly in individuals with chronic kidney disease. Consequently, regulatory bodies have established acceptable daily intake levels to ensure consumer safety. When used within these guidelines, SHMP contributes beneficially to food preservation and quality enhancement.^[2]^[3]

Safety Overview

Regulatory Bodies

FDA (US)

The FDA classifies SHMP as “Generally Recognized As Safe” (GRAS) when used in accordance with good manufacturing practices.^[4]

Health Canada

Health Canada’s Food Directorate permits the use of SHMP in foods like frozen squid under specific conditions, deeming it safe at approved levels.^[5]

EFSA (Europe)

EFSA has evaluated SHMP and established an acceptable daily intake (ADI) of 0–70 mg/kg body weight for phosphates, including SHMP, indicating its safety within these limits.^[6]

WHO (World Health Organization)

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has set a group ADI for phosphates, including SHMP, at 70 mg/kg body weight, reflecting a consensus on its safe consumption level.^[7]

FDA GRAS

U.S. Food and Drug Administration – Generally Recognized as Safe (GRAS)

Current Status

Classified

EWG Rating

Environmental Working Group

EWG Rating: SHMP is rated with a low hazard score in the EWG’s Skin Deep® database, indicating minimal health concerns.^[2]
Level of Caution: The EWG notes that products containing SHMP are allowed for use in EWG VERIFIED™ but must meet use restrictions and warnings based on EWG review of company data.^[2]
Possible Health Risks: Potential concerns include irritation (skin, eyes, or lungs) and contamination concerns, though these are considered low to moderate.^[2]

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More about Sodium Hexametaphosphate

Processed Meats: Hot dogs, sausages, bologna
Dairy Products: Processed cheese, cheese spreads, powdered milk
Carbonated Beverages and Soft Drinks: Cola, root beer, flavored sparkling water

Historical Use

Sodium hexametaphosphate (SHMP) has been utilized since the mid-20th century, primarily in water treatment processes to prevent scale formation and corrosion in pipelines. Its ability to sequester metal ions made it valuable in maintaining water quality and infrastructure integrity.^[8]

Current Exposure

Today, consumers are commonly exposed to SHMP through its inclusion in various food products as an emulsifier and stabilizer, such as processed meats, dairy items, and beverages. Additionally, it is present in some personal care products, including toothpaste, due to its ability to prevent tartar buildup.^[8]

Kidney Stone Formation

SHMP has been studied for its potential to dissolve calcium oxalate, the primary component of kidney stones, suggesting a therapeutic role in preventing stone formation.^[9]

Dental Health

In veterinary studies, SHMP has been effective in reducing dental calculus formation, indicating its potential benefits in oral health applications.^[10]

Biofilm pH Modulation

Research indicates that SHMP, when combined with fluoride, can affect the pH and inorganic composition of dual-species biofilms, which may influence dental caries development.^[11]

Protein Aggregation

Studies have shown that SHMP can induce aggregation of proteins like hen egg white lysozyme, which may have implications for food processing and allergenicity.^[12]

Toxicological Studies

Sodium hexametaphosphate (SHMP) has been evaluated for its safety in various applications, including its use in toothpaste formulations. A six-month clinical trial assessed the anticalculus efficacy and safety of a dentifrice containing SHMP, finding it effective in reducing tartar formation with no significant adverse effects reported during the study period.^[13]

Long-Term Safety

While SHMP is generally recognized as safe for various uses, including in food and dental products, comprehensive long-term studies specifically focusing on its chronic exposure effects are limited. Therefore, while current evidence supports its safety in approved applications, further research is necessary to conclusively determine the long-term health implications of prolonged SHMP exposure.^[14]

High-Risk Groups

Vulnerable populations, such as individuals with chronic kidney disease, may be at increased risk when exposed to sodium hexametaphosphate (SHMP) due to their impaired ability to excrete phosphates, potentially leading to hyperphosphatemia. Additionally, infants and the elderly might be more susceptible to phosphate additives because of their differing metabolic rates and renal functions.^[14]

Health Impacts

In susceptible individuals, excessive intake of phosphate additives like SHMP has been associated with adverse health effects, including vascular calcification and compromised bone health. These effects underscore the importance of monitoring phosphate additive consumption, particularly in high-risk groups.^[14]

Recommended Intake

The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has established a maximum tolerable daily intake (MTDI) for phosphorus from all sources, including sodium hexametaphosphate (SHMP), at 70 mg per kg of body weight per day, expressed as phosphorus.^[15]^[16]

General Safety Level

Sodium Hexametaphosphate is generally recognized as safe (GRAS) for use in food products by regulatory bodies like the FDA, with no significant allergenic potential reported in most research studies.^[17]

Sensitive Individuals

While specific studies on sodium hexametaphosphate are limited, research indicates that occupational exposure to certain metals and solvents can lead to allergic diseases, including occupational contact dermatitis and occupational asthma. These conditions are prevalent in industrialized countries and highlight the importance of preventive measures in the workplace.^[18]

References

Lanigan, R.S., 2001. Final report on the safety assessment of Sodium Metaphosphate, Sodium Trimetaphosphate, and Sodium Hexametaphosphate. International Journal of Toxicology, 20(Suppl 3), pp.75-89. Available at: https://pubmed.ncbi.nlm.nih.gov/11766135/ ↩︎
Environmental Working Group (EWG). 'Sodium Hexametaphosphate.' EWG's Skin Deepu00ae. Available at: https://www.ewg.org/skindeep/ingredients/706070/ ↩︎
Eberhard Ritz, Kai Hahn, Markus Ketteler, Martin K. Kuhlmann & Johannes Mann. (2012). 'Phosphate additives in food-a health risk.' Deutsches u00c4rzteblatt International, 109(4), 49-55. Available at: https://pubmed.ncbi.nlm.nih.gov/22334826/ ↩︎
U.S. Food and Drug Administration (FDA), n.d. 'CFR - Code of Federal Regulations Title 21.' Available at: https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-182/subpart-G/section-182.6760 ↩︎
Health Canada, 2025. 'Notice of Modification to the Lists of Permitted Food Additives to Enable the Use of Sodium Tripolyphosphate, Sodium Hexametaphosphate, Sodium Carbonate, Sodium Acid Pyrophosphate and Sodium Pyrophosphate, Tetrabasic in Frozen Squid.' Available at: https://www.canada.ca/en/health-canada/services/food-nutrition/public-involvement-partnerships/modification-lists-permitted-food-additives-use-sodium-tripolyphosphate-hexametaphosphate-singly.html ↩︎
European Food Safety Authority (EFSA). 'Re-evaluation of the safety of phosphates (E 338-341, E 343, E 450-452) as food additives.' EFSA Journal, 2019. Available at: https://www.efsa.europa.eu/en/efsajournal/pub/5674 ↩︎
FAO/WHO Expert Committee on Food Additives (JECFA), 2025. 'Evaluation of Certain Food Additives and Contaminants.' WHO Technical Report Series 940. Available at: https://www.who.int/publications/i/item/9789241209409 ↩︎
JSTOR, n.d. 'Corrosion Control by Sodium Hexametaphosphate.' Available at: https://www.jstor.org/stable/41232520 ↩︎
Robinson, T.E., et al., 2020. 'Hexametaphosphate as a potential therapy for the dissolution and prevention of kidney stones.' Journal of Materials Chemistry B, 8(24), pp.5215-5224. Available at: https://pubs.rsc.org/en/content/articlehtml/2020/tb/d0tb00343c ↩︎
Stookey, G.K., Warrick, J.M. & Miller, L.L., 1995. 'Effect of sodium hexametaphosphate on dental calculus formation in dogs.' American Journal of Veterinary Research, 56(7), pp.913-918. Available at: https://avmajournals.avma.org/view/journals/ajvr/56/7/ajvr.1995.56.07.913.xml ↩︎
Hosida, T.Y., et al., 2022. 'Effects of Sodium Hexametaphosphate and Fluoride on the pH and Inorganic Components of Streptococcus mutans and Candida albicans Biofilm after Sucrose Exposure.' Antibiotics, 11(8), p.1044. Available at: https://www.mdpi.com/2079-6382/11/8/1044 ↩︎
ACS Omega, 2025. 'Hexametaphosphate, a Common Food Additive, Aggregated the Hen Egg White Lysozyme.' Available at: https://pubs.acs.org/doi/pdf/10.1021/acsomega.3c06210 ↩︎
Liu, H., Segreto, V., Baker, R., Vastola, K., Ramsey, L., & Gerlach, R. (2002). 'Anticalculus efficacy and safety of a novel whitening dentifrice containing sodium hexametaphosphate: a controlled six-month clinical trial.' The Journal of Clinical Dentistry, 13(1), 25-28. Available at: https://europepmc.org/article/MED/11507928 ↩︎
Lanigan, R. S. (2001). 'Final report on the safety assessment of sodium metaphosphate, sodium trimetaphosphate, and sodium hexametaphosphate.' International Journal of Toxicology, 20(Suppl 3), 75-89. Available at: https://journals.sagepub.com/doi/10.1080/10915810152630756 ↩︎
FAO/WHO Expert Committee on Food Additives (JECFA), 2025. 'Evaluation of Certain Food Additives and Contaminants.' WHO Technical Report Series 940. Available at: https://www.who.int/publications/i/item/9789241209403 ↩︎
Health Canada, 2025. 'Sodium hexametaphosphate.' Natural Health Products Ingredients Database. Available at: https://webprod.hc-sc.gc.ca/nhpid-bdipsn/ingredReq?id=446 ↩︎
Food and Drug Administration (FDA), 2025. 'Food Additive Status List.' Available at: https://www.fda.gov/food/food-additives-petitions/food-additive-status-list ↩︎
Kar Kurt, O. & Basaran, N., 2020. 'Occupational Exposure to Metals and Solvents: Allergy and Airway Diseases.' Current Allergy and Asthma Reports, 20(38). Available at: https://link.springer.com/article/10.1007/s11882-020-00931-7 ↩︎

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