Ingredient file // Vitamin or mineral
Sodium Hexametaphosphate
A tartar tool, not a dental treatment
Sodium hexametaphosphate is a manufactured phosphate salt added to some dry foods. It binds calcium in saliva, slowing the formation of new tartar. Dog trials support that use, but the ingredient name alone cannot show whether a particular food delivers the tested effect.
- What it is
- A water soluble sodium phosphate powder that binds saliva calcium before plaque hardens into tartar.
- Made from
- Heated monosodium phosphate
- Main job
- Slows tartar buildup
- Typical amount
- A kibble trial used 300 ppm
- Watch for
- Total phosphorus in a kidney diet
- Not the same as
- Sodium tripolyphosphate
Our read // In our catalog
In 1 of every 41 foods we track
Share of foods that list it
2%
64 of the 2,595 foods with an ingredient list on file, from 6 brands. 41 dry dog food, 23 wet dog food.
Each square is 1% of the catalog
Where it sits on the label
Median position 17. In the top five of 0 foods, so it is usually a minor ingredient.
Above the salt
Usually listed after the salt, which caps it at roughly 1% of the recipe in 73% of foods.
Price per lb
Median of the cheapest bag price across 37 priced foods, 36% below the catalog. The price is the food's, not the ingredient's.
Who leans on it
34%
of the foods that list it are from Nutro. 6 brands use it in total.
What it is
How it is made
This manufactured phosphate comes from the chemical supply chain. Producers heat monosodium phosphate into a melt, cool it into glass, then mill it into powder sold for food and other uses.7,9,11
- 01 // Source Monosodium phosphate Production starts with a solution of monosodium phosphate, a sodium salt of phosphoric acid.
- 02 // Process Heated in stages Heating first forms a pyrophosphate, then drives it into a molten chain of phosphate units.
- 03 // Process Cooled and milled The melt cools into a glassy sheet that is broken down into granules or powder.
- 04 // Output Food grade powder The white powder arrives ready to mix into kibble or apply as a surface coating.
What is in it
Composition, dry matter
30
% phosphorus
The calculated share in an ideal dry hexaphosphate molecule. This mineral additive's label position cannot reveal the finished food's phosphorus level.
Why it is in the bag
What the manufacturer gets
-
01
Slows new tartar
It binds calcium in saliva, leaving less available to harden plaque into tartar. Dog trials measured less new tartar when it was added to kibble or biscuits.1,2,3
-
02
Fits dry food production
Manufacturers can mix the powder into kibble or put it on the surface. A controlled kibble trial found less tartar with either placement.2,9
-
03
Available at scale
The original researchers sought a food grade material available at reasonable cost. Food processing and water treatment also use this phosphate, supporting a broader supply chain.1,9
How much A kibble trial tested 300 ppm, while a separate biscuit trial used a 0.6% surface coating.2,3
Our read // The claims
What the evidence supports
Strong: controlled studies in dogs agree. Some: small or mixed dog data. Thin: mechanism or lab work only. None: nothing, or the evidence points the other way.
-
Brands say
It reduces new tartar on dogs' teeth
Evidence
- Strong
- Some
- Thin
- None
In a randomized 25-dog, 90-day kibble trial, treated diets reduced tartar by up to 47%. A separate 27-Beagle series also found reductions. The measured outcome was new tartar.1,2
-
Brands say
It works equally well anywhere in kibble
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
One 25-dog trial found less tartar whether the phosphate was mixed in or coated on kibble. An earlier series emphasized surface coating. An ingredient list gives neither placement nor dose, so it cannot promise the same result.1,2
-
Brands say
It prevents gum disease
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
Veterinary dental guidance says visible tartar control does not adequately address disease beneath the gumline. The 27-Beagle series scored tartar after short test periods, not gum disease or tooth loss. Less tartar does not show disease prevention.1,6
-
Owners say
It removes tartar already on teeth
Outruns the evidence
Evidence
- Strong
- Some
- Thin
- None
The controlled trials began with a dental cleaning and then measured newly formed tartar over 4 weeks or 90 days. They did not test removal of deposits already attached to teeth.1,2
Straight answers
What owners ask
-
Q01
Is it just filler?
NoIt has a specific job at a small tested amount: slowing the buildup of new tartar. It does not supply the recipe's calories or protein, and adding more would not make it a better food.1,2
-
Q02
Does it replace brushing?
NoIts trials measured tartar. Brushing removes plaque, while veterinary dental guidance says visible tartar control does not adequately address disease beneath the gumline. Keep brushing even if a food makes a tartar claim.1,6
-
Q03
Does it add too much phosphorus?
DependsThe salt contains phosphorus, but its place on an ingredient list gives no amount for the finished food. For a dog with kidney disease, get the food's phosphorus level and compare it with the dog's renal diet target.8,12
-
Q04
Is another dental phosphate better?
No clear winnerOne kibble trial favored hexametaphosphate, while a 40-Beagle study found tripolyphosphate at least as effective. The food's tested dental result matters more than choosing between those names.2,4
Who uses it
Brands, best sellers and the company it keeps
Top brands, by foods that list it
Usually listed with, share of the foods that list it
- Chicken 73%
- Chicken Fat 48%
- Natural Flavor 47%
- Chicken Broth 36%
- Dried Plain Beet Pulp 36%
- Brown Rice 34%
- Corn 34%
- Brewers Rice 28%
- Chicken By-Product Meal 28%
- Chicken Meal 27%
- Dried Egg Product 25%
- Carrots 23%
Our read // On the bag
Check the dental evidence and phosphorus level
Low on a bag's ingredient list, sodium hexametaphosphate signals a small additive with a real tartar-control purpose. The list cannot show its dose or placement. Judge a dental claim by results for that food and keep brushing. If your dog has kidney disease, ask for the finished food's phosphorus level.
Sources
What we read
Checked September 30, 2026.
- 1 Effect of sodium hexametaphosphate on dental calculus formation in dogs
- 2 Sodium tripolyphosphate and sodium hexametaphosphate in preventing dental calculus accumulation in dogs
- 3 Hexametaphosphate-Coated Snack Biscuits Significantly Reduce Calculus Formation in Dogs
- 4 Effect of Pellet Food Size and Polyphosphates in Preventing Calculus Accumulation in Dogs
- 5 Effects of dietary phosphates from organic and inorganic sources on parameters of phosphorus homeostasis in healthy adult dogs
- 6 American Veterinary Dental College Position Statement on Anesthesia-Free Dentistry
- 7 Sodium Polyphosphates, Glassy
- 8 Treatment Recommendations for CKD in Dogs
- 9 Water Treatment Chemical Supply Chain Profile: Sodium Salts of Polyphosphates
- 10 Sodium Hexametaphosphate From China
- 11 Sodium Hexametaphosphate Food Grade
- 12 Na6P6O18 (Sodium hexametaphosphate) molar mass