Sodium hexametaphosphate (SHMP) is commonly included in certain dog dental products and marketed for “tartar control.”
But understanding whether SHMP delivers meaningful benefit depends on how it works and how it is delivered, especially in powder form.
What Is Sodium Hexametaphosphate (SHMP)?
SHMP is a synthetic compound that binds calcium.
Tartar forms when calcium in saliva hardens plaque on the tooth surface.
Plaque is a soft layer of bacteria.
Tartar is hardened plaque (calculus).
SHMP works by grabbing onto calcium before it can attach to plaque and harden.
It only works where it physically touches the tooth.
It does not enter the bloodstream.
It does not change saliva.
It does not affect bacteria directly.
How SHMP Works
SHMP works through direct contact with the tooth surface.
To affect mineralisation and slow tartar formation, it must:
• Be present in sufficient concentration
• Remain in contact with plaque on the tooth surface
• Interact before mineralisation occurs
If it does not physically touch the tooth, it cannot work.
It does not:
• Enter the bloodstream
• Influence saliva composition
• Modulate oral biofilm upstream
If you want to understand the difference between surface ingredients and ingredients that work from within, you can read more about
how systemic dental powders work for plaque and tartar control.
Where SHMP Is Most Effective
SHMP performs best when applied directly to the tooth surface, for example:
• As a coating on dry kibble
• In products designed to maintain extended contact with teeth
Chewing can increase contact time, giving SHMP a more consistent opportunity to bind calcium before mineralisation occurs.
Even then, SHMP mainly slows tartar formation; not reduce plaque formation.
Plaque is the bacterial source of long-term dental disease. Tartar is a consequence.
Targeting plaque before it mineralises remains critical.
Limitations in Powdered Supplements
When SHMP is included in a powder mixed into food:
• It disperses throughout the meal
• Contact with tooth surfaces is brief
• Saliva dilutes it rapidly
• It loses effective surface exposure
Because SMHP requires sustained contact with tooth surfaces, powdered delivery does not reliably provide that exposure.
If contact time is minimal, the ingredient’s function is compromised.
Plaque vs Tartar
Plaque forms as a bacterial biofilm on the tooth.
Tartar is the result of plaque mineralising with calcium.
SHMP may help slow tartar hardening. It does not stop plaque from forming.
If plaque continues to build up, gum irritation and bad breath can still develop.
Ingredients that influence the oral environment through saliva prevent plaque accumulation earlier in the process.
That difference affects long-term prevention.
Other surface-dependent additives, such as activated charcoal in dog dental powders, have similar limitations in powdered form.
Why DentaMax Does Not Include SHMP
DentaMax is formulated with a single clinically studied ingredient: Ascophyllum nodosum.
It is taken daily with food and works from within the body. After digestion, its active compounds circulate and influence the oral environment through saliva.
The aim is straightforward:
• Support control of plaque formation
• Help limit tartar buildup
• Improve bad breath linked to plaque and gum irritation
• Provide consistent daily oral support
SHMP works differently. It must sit directly on the tooth surface to bind calcium and slow the hardening of tartar. If it does not remain in contact with the teeth, it cannot do its job.
A nominal amount of powder mixed into food is swallowed quickly. That limits how long SHMP can remain on the teeth, making it poorly suited to this format.
DentaMax does not include SHMP because its benefit depends on sustained surface contact, something a dental powder cannot reliably provide.
Instead, DentaMax delivers a full daily dose of clinically studied Ascophyllum nodosum without its natural integrity or by adding synthetic mineral binders such as SHMP, which are effective only through prolonged surface contact with the tooth and do not work effectively in powdered form.
For more on the active ingredient itself, see Ascophyllum nodosum for dogs and its clinically studied plaque-control benefits.
Is SHMP Unsafe?
SHMP is commonly used in food formulations and is not inherently dangerous when used appropriately.
The issue is not whether it is approved for use.
The issue is whether it makes sense in a daily powder that does not stay on the teeth long enough to work as intended.
That constraint is often overlooked.
The Bottom Line
Sodium hexametaphosphate binds calcium at the tooth surface.
It only works if it stays in contact with the teeth.
In powdered dental supplements mixed into food:
• Contact time is short
• It is swallowed quickly
• SHMP does not act systemically
• It does not influence saliva
• It does not reduce plaque formation
An ingredient that works only on the surface and only with enough contact time has clear limitations in a powder.
That is why DentaMax does not include SHMP.
For a broader comparison of locally available dental powders, see our guide to dog & cat dental powder in South Africa.