Dog Dental Chews: Cleaner Teeth, But What About Long-Term Health?
Last week, we took a closer look at whether dental chews really clean your dog's teeth. .
The answer wasn't black and white. Some dental chews have demonstrated that they can reduce plaque, tartar or both.
But we ended that conversation with an important point:
"Reduces plaque or tartar," "cleans your dog's teeth," and "is something I'm comfortable giving my dog every day for long-term health" may not all be wrapped up in one chew.
So this week, we're asking a different question: What does your dog have to swallow to get that 10,000 watt smile?
In other words... what are the ingredients in dog chews and are they safe for long term use?
If you are giving your dog something every day, potentially for years, their whole health has to be part of the conversation.
🔎 What's Actually in a Dental Chew?
A dental chew has to maintain the right texture, stay fresh on a shelf and taste good enough that your dog wants to eat it.
When we dug into the ingredients in dental chews we saw a lot of variations:
- Starches/flours & structural ingredients: wheat flour, rice/brewers rice, potato starch, modified food starch, malted barley flour, dextrin/maltodextrin, wheat gluten, soy protein, pea protein, powdered cellulose. These build the chew and create texture.
- Humectants/texture agents: glycerin, propylene glycol, gelatin. They help produce or maintain that flexible, chewy consistency.
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Palatability ingredients: natural flavor, poultry/chicken flavor, animal digest, natural liver flavor, natural smoke flavor, fats, chicken by-product meal, dried chicken, sugar, honey, and artificial flavors. This category can get surprisingly extensive because the dog has to want to chew it.
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Preservatives: potassium sorbate, sorbic acid, calcium propionate, mixed tocopherols, BHA, BHT, ascorbic acid. These aren't all equivalent from a formulation or safety perspective; their common job is preservation/shelf stability. BHA is currently being re-assessed by the FDA for safety concerns. BHT (butylated hydrotoluene) may be linked to liver enzyme activity, thyroid function, and reproductive functions. Personally, I'd not give my dog a chew with these ingredients.
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Colors: fruit/vegetable juice colors, turmeric, titanium dioxide, and in some formulas synthetic colors such as Yellow 5 and Yellow 6. Again, I'd not want my dog chewing and consuming a product with added colors.
- Minerals/phosphate ingredients: mono- and dicalcium phosphate, bone phosphate, calcium carbonate, phosphoric acid, etc.
- Added vitamins/minerals: vitamins A, D, E and B vitamins; zinc, iron, copper, manganese, selenium, iodine, calcium, etc. Some chews are essentially fortified treats.
- Miscellaneous functional ingredients: lecithin/emulsifiers, monoglycerides, sodium bicarbonate, salts, acids, herbs like parsley or spearmint, oils, and sometimes supplemental ingredients such as glucosamine/chondroitin.
- Dental/tartar-control phosphates: sodium hexametaphosphate (SHMP), sodium tripolyphosphate (STPP), and potentially other phosphate compounds.
So... what did we learn?
Some ingredients simply make the chew ... chewable!
Some ingredients - a lot of them actually - I'd not give my own dogs.
Others are there specifically to create the dental benefit. That is where we want to focus.
🧪 Meet Sodium Hexametaphosphate
Sodium hexametaphosphate or SHMP is used in some dental chews because it binds minerals such as calcium, helping interfere with the mineralization of plaque into tartar on the teeth.
In canine dental research, applying SHMP to the surface of food or biscuits significantly reduced dental calculus. Interestingly, researchers found that a coating containing just 0.6% SHMP produced near-maximal tartar-control benefits, with higher coating concentrations not producing a clear dose-dependent improvement.
That raises an interesting question.
If SHMP's dental benefit comes from what it does while it's in contact with the teeth, how much does a dog actually swallow while trying to get that benefit?
That's not a question the dental efficacy research answers.
The published research demonstrates that SHMP can reduce tartar. It doesn't necessarily tell us how much SHMP a dog ultimately ingests from dental chews, what that contributes to the dog's total daily phosphorus exposure, or what repeated exposure looks like over years of daily use.
And that's the distinction we're interested in.
There is a realtime dental benefit happening in the mouth — followed by an ingredient the rest of the body has to process after it's swallowed.
Why Does SHMP Give Us Pause?
Sodium hexametaphosphate is an inorganic phosphate.
Phosphorus itself isn't bad. It's an essential nutrient that dogs (and humans) need for healthy bones, cells and normal body function.
But the source — and the dose — matter.
Phosphorus occurs naturally in many foods, but manufacturers can all add phosphorus (inorganic phosphate compounds) for specific purposes. These added phosphates can be more readily available for absorption than phosphorus naturally bound in food.
SHMP is one of those added inorganic phosphates. In dental products, it isn't there because your dog needs more phosphorus in their diet. It's added specifically to help control tartar.
Research in dogs consuming diets containing higher levels of highly available inorganic phosphorus (added phosphorus) has found changes in the body's regulation of calcium and phosphorus, including changes involving the kidneys and hormones responsible for maintaining mineral balance.
And at sufficiently high exposures, animal research involving SHMP and related phosphates has reported kidney and mineral-metabolism effects.
In other words, this isn't a situation where dose doesn't matter. It matters enormously.
The kidneys play an important role in regulating phosphorus and removing excess phosphorus from the body. As phosphorus exposure increases, the body has more phosphorus to regulate and excrete.
We're not going to make you sit through a lesson on phosphorus metabolism, parathyroid hormone and FGF23, but the takeaway is important:
Repeated exposure to highly available inorganic phosphorus isn't something we think should be dismissed simply because the ingredient has a demonstrated dental benefit.
⚖️ What Does the Research Actually Prove?
There are no studies that show a direct link between the amount of SHMP in a daily dental chew and kidney disease in your dog.
However, there are some high-dose animal studies involving SHMP and related phosphates that have reported effects involving the kidneys, bones and mineral metabolism. Unfortunately, those doses can't simply be compared with the amount a dog receives from a dental chew.
And that's part of the problem: we don't necessarily know from an ingredient panel how much SHMP a dog is consuming.
To really understand that exposure, we'd need to know the amount of SHMP in the chew, how much the dog consumes relative to body weight, how much inorganic phosphorus that contributes, what else is coming from the dog's diet, and how frequently the product is given.
Dose matters. Total diet matters. Frequency matters. Duration of exposure matters.
So... we do what we always do at 4-Legger. We stand on the side of caution. We created dog shampoo without synthetic ingredients because we believe they can cause long term harm.
The same with dental products.
When we're choosing ingredients for something intended to be used on a regular basis, potentially for years, we don't think we need to wait for proof that an ingredient causes harm before deciding we'd rather formulate without it.
We look at what an ingredient does, what we know about repeated exposure, what we don't know, and whether we actually need that ingredient to accomplish our goal.
🌿 That's Why We Chose a Different Approach
When we developed 4-Legger Mint Fresh Dental Powder , we weren't trying to create an edible chew because we were not comfortable formulating a chew using ingredients that could potentially, although not proven, cause long term harm to a dog's body.
We wanted something that could be used while physically cleaning the teeth and gumline with a toothbrush, finger brush, gauze or another gentle dental tool your dog accepts.
That means our powder doesn't have to hold together like a chew.
It doesn't have to stay soft.
It doesn't need starches or flour to create structure.
It doesn't need glycerin to maintain a chewy texture.
And we don't need SHMP to chemically interfere with tartar formation.
That allowed us to keep the formula incredibly simple:
- Baking soda: Provides gentle cleaning action and helps neutralize acids and odors in the mouth rather than simply masking bad breath.
- Sea salt: Provides gentle abrasive action to help physically clean the teeth and naturally stimulates saliva production. Saliva is an important part of the mouth's own defense system, helping rinse the teeth, buffer acids and maintain a healthy oral environment.
- Peppermint essential oil: Provides a naturally fresh mint aroma without artificial flavors or fragrances and contrary to bad google advice, is not summarily toxic to dogs.
Three ingredients. That's it.
🪥 The Goal Is Still to Remove Plaque
This brings us back to what we talked about last week.
Plaque is a sticky bacterial biofilm. One of the most direct ways to deal with it is to physically disrupt it before it has the opportunity to accumulate and mineralize into tartar.
That's the foundation of our approach.
You provide the mechanical cleaning with a soft-bristled toothbrush, finger brush, gauze or another gentle tool your dog accepts.
Mint Fresh Dental Powder complements that cleaning.
You don't rely on a dental chew with questionable ingredients. Instead, you can give your dog safer chews because they aren't doing double duty - they are providing mental stimulation - not also trying to keep their teeth clean.
And because you're doing the cleaning, you control where it happens — including the tooth surfaces and gumline that chewing may not consistently reach.
For us, good dental care shouldn't stop at the teeth. The choices we make for our dogs' mouths should make sense for the whole dog.
Frequently Asked Questions
What is sodium hexametaphosphate in dog dental chews?
Sodium hexametaphosphate (SHMP) is an inorganic phosphate used in some dental products to help reduce tartar formation. It binds minerals such as calcium, interfering with the mineralization of plaque into dental calculus.
Does sodium hexametaphosphate work?
Yes. Research in dogs has demonstrated that SHMP can reduce dental calculus.
Our concern isn't whether it works. We think dental efficacy and the implications of routinely swallowing an ingredient are two separate questions.
Does SHMP cause kidney damage in dogs?
Current research does not establish that the amount of SHMP used in dental chews causes kidney damage in dogs.
However, research involving higher dietary exposure to highly available inorganic phosphorus has identified effects on phosphorus regulation, including processes involving the kidneys. High-dose animal studies involving SHMP and related phosphates have also reported kidney, bone and mineral-metabolism effects.
Those findings are enough for us to question routine long-term exposure, particularly when we can formulate without SHMP.
Why doesn't 4-Legger use SHMP?
Because effectiveness is only one part of how we evaluate an ingredient.
We also consider what our dogs have to swallow to obtain that benefit, what is known about repeated exposure, what remains unknown and whether the ingredient is necessary.
For Mint Fresh Dental Powder, it isn't.
What's in 4-Legger Mint Fresh Dental Powder?
Just three ingredients: baking soda, sea salt and peppermint essential oil.
It contains no sodium hexametaphosphate (SHMP), artificial colors or flavors, sweeteners, glycerin, starches or flour.
