Sodium Hexametaphosphate

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

1. 01 // Source Monosodium phosphate Production starts with a solution of monosodium phosphate, a sodium salt of phosphoric acid.
2. 02 // Process Heated in stages Heating first forms a pyrophosphate, then drives it into a molten chain of phosphate units.
3. 03 // Process Cooled and milled The melt cools into a glassy sheet that is broken down into granules or powder.
4. 04 // Output Food grade powder The white powder arrives ready to mix into kibble or apply as a surface coating.

1. 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

2. 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

3. 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

1. Brands say

   It reduces new tartar on dogs' teeth

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. 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

2. Brands say

   It works equally well anywhere in kibble

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. 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

3. Brands say

   It prevents gum disease

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. 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

4. Owners say

   It removes tartar already on teeth

   Outruns the evidence

   Evidence

   1. Strong
   2. Some
   3. Thin
   4. 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