HealthyMouth Water Additive: Does It Help Prevent Dental Disease?

I am often asked by clients or readers about specific products, and while I certainly can  only investigate a small proportion of all the stuff marketed to pet owners, I try to look at as many of these things as I can. Some of my colleagues have begun using a product called HealthyMouth , a water additive reported to reduce accumulation of plaque and retard the development of dental disease. This product has received a seal of acceptance from the Veterinary Oral health Council (VOHC) and  an endorsement from Dr. Fraser Hale, a dental specialist and someone who generally takes a skeptical, evidence-based approach to dental therapies. Dr. Fraser has gone from being skeptical of the product to actively recommending and distributing it. These are sources I believe are trustworthy, so I thought I ought to take a closer look at the product. In keeping with my general approach, I will review the product in terms of the following general issue: 

1. Basic plausibility for proposed effect/mechanism of action
2. Pre-clinical, non-target species research
3. Clinical trials
4. Marketing claims 

Individual Ingredients
The product ingredients list is extensive, though specific quantities/concentrations are not provided. Only two are described as “active” ingredients, papain and zinc gluconate, but I will discuss several others that appear to be included for some specific effect. Theoretical rationales are provided for some ingredients but not others. Many ingredients are described as “organic,” which I suspect has little relevance. The dog and cat products appear from the ingredient list to be identical except for the addition of the amino acid taurine to the feline product.

1. Pomegranate- No specific claim is made about this ingredient.
There are a few in vitro trials that suggest anti-bacterial effects from pomegranate juice. There are also a number of human clinical trials suggesting anti-plaque and anti-bacterial effects for oral rinses containing this ingredient (1,2). There appear to be no clinical trials in dogs other than the two unpublished studies conducted by HealthyMouth, and no trials at all in cats. Clinical trials in humans and lab animal studies show little risk, though allergic reactions in humans have been reported, and there are some concerns about possible interference with the metabolism of other supplements or drugs.

2. Yucca- I was not able to find any in vitro research suggesting a benefit for yucca extract in preventing or treating dental disease. There have been a couple clinical trials of one yucca extract in dogs (3) and one in cats (4) reporting some decrease in the odor of flatulence, and no significant adverse effects were reported. There are reports of yucca extracts causing gastrointestinal symptoms. I was not able to find any clinical trials of yucca extract as a preventative or therapeutic for dental disease in humans or in dogs or cats.

3. Zinc gluconate- The claim made for this ingredient is that ” zinc gluconate operates as an antibacterial agent.” There are clinical trials of zinc gluconate containing rinses and toothpastes in humans which appear to show decreased plaque and gingivitis, but the compound is almost always combined with triclosan or other antibacterials, so it is unclear what role the zinc itself has in any effect seen. There are no clinical trials investigating the use of this agent in preventing or treating dental disease in dogs or cats. Excessive zinc ingestion can cause serious and even life-threatening complications.

4. Blueberry- I found one study suggesting a particular blueberry extract might have a weak effect reducing the aggregation of bacteria found in the human mouth (5). There appears to be no lab animal, or clinical trial evidence in humans or other animals that blueberry is useful in the prevention or treatment of dental disease. Blueberry’s are reported to contain substances which have anti-oxidant properties, but the clinical significance of this is unclear, and no apparent connection exists to prevention of dental disease.

5. Papain- A combination of proteolytic enzymes found in papaya, papain does not appear to have been studied extensively as an agent for prevention and treatment of dental disease, though it is occasionally found in toothpastes. I was not able to find any clinical trials in humans, or in dogs or cats regarding dental disease. There are some safety concerns as large amounts have been reported to cause perforation of the esophagus in humans, allergic reactions are possible, and there is some potential risk of reducing blood clotting function, especially in combination with some other herbal ingredients including cloves which is one of the flavoring agents in HealthyMouth.

6. Vitamins B2 and C- These appear to be included as “anti-oxidants” and to “increase the immune response.” The notion of boosting the immune system is a meaningless marketing device and while there is some preliminary suggestion that preventing oxidative damage can sometimes be a good thing, oxidation is also one of the ways the body suppresses cancer and fights infection, so it is not appropriate to assume that reducing it, even if these substances actually do that in a living animal, is a good thing.

7. Clove and cinnamon- These are apparently added as flavoring agents, and I found no research to suggest benefit or risk associated with them in dogs and cats. I wouldn’t expect them to be especially appealing to cats, but the company claims they love it.

Clinical Trials
As I mentioned, HealthyMouth has been awarded the Veterinary Oral Health Council (VOHC) seal of acceptance. VOHC is an independent organization that reviews the evidence for products claimed to have value for prevention and treatment of dental disease in animals. The organization requires clinical trial evidence to support product claims, and they have pretty specific protocols to ensure these claims are adequately demonstrated. However, I still have some concerns about the trials HealthyMouth uses to support its product claims.

As I often point out, all of us have biases about the ideas and beliefs we hold. We naturally believe our hypotheses to be true, and this can lead us to see what we want or expect to see, to focus on confirming information and ignore or minimize contrary information (e.g. confirmation bias and cognitive dissonance). And non-ideological motives, such as financial incentives, can also influence our interpretation of what we see even if our intentions are quite honest. It is well established in human medicine that trials funded by industry, for example, tend to have findings favorable to the products of the funder. The purpose of formal clinical trials is to help us test our ideas in a way that hopefully prevents these biases from inappropriately influences our findings.

It is important to be aware of the potential biases involved in a clinical study, not because this information allows us to automatically dismiss the findings but because it helps us spot weaknesses in the methods and evaluate the results in context.

In the case of HealthyMouth, the two clinical studies in dogs were both funded by the company that manufactures the product. And thought the chief investigator, Dr. Jean Dodds, is a well-respected veterinarian who has done much fine work for the veterinary  profession and animal welfare, she is also a prominent advocate of “holistic” veterinary medicine, having even received the Holistic Veterinarian of the Year award from the American Holistic Veterinary Medical Association, an organization I’ve discussed frequently before. These facts are relevant because they indicate the high potential for a bias favorable to the product in these trials, and so we must look carefully at the methodology of the trials to see if there are adequate controls.

It is difficult to evaluate all the details of the methodology since the trials have not, as far as I can tell, been through peer review or been published in the scientific literature. The information I evaluated about them comes from the HealthyMouth web site. It appears that two trials, with 40 different dogs in each study and a duration of 28 days (requirements of the VOHC protocol) were conducted by Dr. Dodds in a greyhound dog rescue center and blood bank she founded and manages. The advantage to this, apart from logistics, is that the husbandry of the dogs was likely pretty uniform, which reduces sources of variation between groups. The disadvantage is that the dogs were all of one breed (and one in which dental disease is a particular problem), and the conditions were likely very different from those experienced by typical pet dogs.

The VOHC standards recommends randomization of subjects, but it does not appear that procedure was used in this study. Subjects were allocated to groups based on kennel housing so that the access to treated or untreated drinking water could be more easily controlled. This introduces some small potential source of difference between groups other than the treatment itself.

The dogs had a full dental cleaning under anesthesia at the start of the trials, and their plaque scores measured at intervals, as recommended in the VPHC protocol. A big concern about the study, however, is that there was apparently no blinding. The treated and untreated water were easily distinguished, and the staff managing the dogs and evaluating their oral health were apparently aware of which group they were in. This always introduces a strong potential for bias, and it is especially a concern in a trial like this where there is a strong presumption of safety and efficacy in advance on the part of the organizers of the trial (the company making the product) and possibly among the investigator and her staff. In any case, the evidentiary  value of a clinical trial is substantially lower if it is not properly and effectively blinded, and such trials almost always find a positive treatment effect.

In any case, the trials both showed a strong positive effect on plaque scores. No trials have yet been made public in cats, and no independent evaluation of HealthyMouth appears to have been done.

Marketing Materials
As is probably inevitable, the marketing of this product involves a lot of “satisfied customer” testimonials. Stories of dogs and cats who apparently experienced great benefits are told, and of course no stories from pet owners who do not believe their pets befitted are told. This creates the impression of a safe and effective product, but of course it is a form of advertising, not a reliable source of information about whether the product actually works.

Dr. Hale gives the company founder credit, appropriately in my opinion, for marketing HealthyMouth as an adjunct to appropriate home and professional dental care, not a magic cure-all or substitute for other, established preventative and treatment methods. This is a point in the company’s favor.

Not so encouraging is the frequent use of words like “natural” and “artificial” to imply that the product must be safe. The advertising even goes so far as to claim there are “no chemicals” in the product, which is nonsense since water, blueberry juice, and every other ingredient is a “chemical.”

As I have often pointed out, botulism and uranium are “natural” and polio vaccine and penicillin are “artificial,” so these words don’t really mean what they are implied to mean. In any case, several of the ingredients have recognized health risks in humans, and most have not apparently been tested for safety in dogs or cats. And it is impossible to tell from the web site how much of the various ingredients are in the product, so no definitive statements about safety can be made.  I would be surprised if there are any significant risks from the product since it would require an awful lot of most of the ingredients to be dangerous as far as I can tell, so I’m not especially worried about the safety issue. But the claims of safety are really assumptions based on the naturalistic fallacy, and supposedly safe herbal and homeopathic remedies have turned out to be harmful in the past (e.g. cinnamon bark and homeopathic belladonna), so at least a little caution is appropriate.

There are some very limited in vitro and human clinical data to suggest it is plausible that the ingredients in this product might have some benefit in preventing dental disease. The only research actually testing the product in a veterinary species (dogs) showed benefits, but some caution is warranted in interpreting these results because they are unpublished, industry-funded trials with a lack of robust methodological controls for bias and other non-treatment effects. There is no significant evidence of any real risk from the product, though it doesn’t appear that most of the ingredients, alone or in combination, have been tested for safety in cats and dogs. The company generally markets the product in a responsible way, though it does make use of some misleading advertising strategies such as promotion through testimonials and invocation of the naturalistic fallacy.

Overall, I am inclined neither to recommend the product nor to recommend against it. I applaud the company for taking the first steps in conducting the research necessary to obtain VOHC approval, and I hope additional research, ideally independent and better designed, is eventually carried out to further clarify whether this product has real safety and meaningful efficacy. I agree wholeheartedly with the company that dental disease is a serious condition and that most pets do not receive adequate preventative care or treatment, so I hope additional research does eventually show this product to be a useful adjunct to other oral care practices, but I think it the case has not yet been effectively made.

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73 Responses to HealthyMouth Water Additive: Does It Help Prevent Dental Disease?

  1. skeptvet says:

    I have not seen any additional studies. Since it is not required to have a prescription drug label, the company is not required to conduct clinical studies. The one done was to get a seal of approval from the Veterinary Oral Health Council, but at this point I’m not optimistic that more research will be done.

  2. kittehs says:

    Thank you for your prompt reply!

  3. Katharine Cashman says:

    If “healthy mouth” is so great, why isn’t there a product available for humans?
    If it is allowing the calculus to be softer,wouldn’t the enamel be softened ( similar to acids on human teeth), as well causing sensitivity/enamel ditching in the future?
    I’m not sold yet.

  4. Michelle says:

    Great discussion!

    I’ve been giving Healthy Mouth to my cats for 6 months now and I can barely keep up to their consumption needs. I have 3 cats thus three water bowls and I put HM in only one of them and this bowl gets refilled 2-3 times more frequently than the other 2.

    I bought the product 5 years ago, initially for my dog at the advice of a Dental Vet, however she never liked it. I tried using it on my geriatric kitties but they scoffed at it. Fast forward 4.5 years to present day and 2 new kitten rescues have come into my home. They both had horrendous breath possibly due to their difficult beginnings in life, I just don’t know, but HM has definitely cleared up the bad breath so I’m keeping it!
    Could I substitute Chlorophyll for HM? Possibly, and I just may try it, but for now I’m sticking with this product because it is doing what it advertised it would and unless or until that changes why would I change anything?

  5. Anne T says:

    I have a small maltese cross that I rescued two years ago. She came to us with severe dental disease, we believe she’s about 7, but we can’t be sure. Our vet cleaned and removed some teeth just after she arrived. About a month ago I felt they needed cleaning again and after I picked her up they pretty much pushed this product onto me to give her to control tartar build up in the future. I paid $65 for a small bottle (Australia) and I thought, ok, if it will help her, I’ll use it. Now, after using it for four weeks, I’ve noticed the last few days she hasn’t been herself. I’ve kept a close eye on her and find her urine is green. Is this normal, as the colour of Healthy Mouth is green. Is it a case of what goes in must come out. But I do notice a lot of sediment settles in her water bowl, and it makes me wonder if this sediment is also building up in her kidneys. I’m ready to stop using it and seeing if she returns to her normal self pretty quickly. I can’t help but think that not enough long term research has taken place on this product. I want to thank SkeptVet for looking in to this product and opening up discussion about it.

  6. v.t. says:

    Anne T, I can’t speak for skeptvet nor his expertise, but if you’re worried, you should be able to take a urine sample in for your vet to take a closer look for anything that may or may not be worrisome – or he may ask that you bring in your little guy for collecting urine and testing.

  7. v.t. says:

    My mistake, Anne, your little girl, rather!

  8. Pf says:

    I am very glad I found this analysis of Healthymouth and your website, Dr “Skepvet”. I did a search specifically to see what reviews have been done on this product. Yours is the only one I could find. Unlike other veterinary products sold online with user feedback, Healthymouth has none because of its limited distribution. While user comments are unreliable, I find there becomes a certain “critical mass” of opinions at some point that would not exist if a product had no efficacy at all. Hundreds of positive “5 star” reviews are harder to debunk than a handful. As for Healthymouth, although it was recommended indirectly by a very reputable veterinary dental specialist (“any product on the VOHC website”), I still had my doubts. Doubt 1. A lot of natural ingredients like blueberry, pomegranite and yucca sound more like a nutritional supplement list that I would similarly question if it were for humans. 2. Huge (virtually unjustifiable) cost for relatively inexpensive ingredients. This was a big red flag for me and left me with the impression that this company went out of its way to get the VOHC approval as a marketing tool to vets and customers to justify the high price rather than the efficacy of the product itself. In other words, how many other veterinary dental products would be equally as effective had they underwent the expense of all the comprehensive VOHC required testing? How many would be better? We have no idea because there are no others. Having the approval of VOHC says absolutely nothing about the efficacy of this product *in comparison to other gels sprays and water additives* because there are no other gels sprays and water additives that have VOHC approval. All we know is that Healthymouth “works” under the conditions of their studies. 3. I immediately questioned if there were some sort of connection (and if so, what) between the makers of Healthymouth and VOHC because of the obvious marketing posture and extremely high price with seemingly interchangeable information between the two sites cross referencing each other. My sense is that the one true active ingredient in Healthymouth is Zinc gluconate which is found in many vet dental products and generally accepted to work, I believe. Again, because no other sprays, gels water additives have the VOHC approval, we have no idea what would happen if another company tested and marketed plain water with zinc gluconate alone. My guess is that results would be similar. And who’s to say I am wrong?

    My biggest question, however, has to do with the already generally tried and tested enzymatic alternatives to this product, like glucose oxidase and lactoperoxidase, for example. Do we have any evidence of the efficacy of all these common enzymatic-based dental treatments (especially for cats)? CET Home dental care makes toothpaste with these enzymes (also recommended by many vets) as does Oratene, whose antiseptic oral gel contains even more different enzymes. I believe enzymes are also very safe for pets from what I understand which makes sense conceptually anyway. There are also enzymatic water additives gels and sprays. So, Dr. “Skepvet”, what can you say about the enzymatic dental treatments out there on the market? They are certainly a lot cheaper than Healthymouth. Is healthy mouth really 10 times better than Oratene gel…to justify the 10 fold difference in price?

  9. skeptvet says:

    I haven’t investigated the claims for various enzymatic products, so I don’t have a position on those. The VOHC standard is low (one trial funded and run by the manufacturer), but it is all we have right now, and likely at least a little better than the complete absence of evidence for everything else. Confidence should always be proportional to the strength of the evidence, and what we have is still quite weak. It is generally agreed that the most reliable form of home care is brushing, but when that isn’t an option these other products are not unreasonable things to try, they just aren’t backed by really robust research.

  10. Michael Wood says:

    Hi Guys, can someone tell me why I can’t buy health mouth in Australia?


  11. Susan Gardner says:

    I recently started using HealthyMouth on my 13 year old dachshund. Since then, she has had 2 bouts with incontinence while sleeping. Could they be related?

  12. skeptvet says:

    Given the paucity of research, it is impossible to completely rule this out. However, there is also no particular reason to expect this as a side effect, I have not seen this reported for other dogs on Healthy Mouth, and there are plenty of other causes for this relatively common problem. I would have your dog checked out, but I think the HealthyMouth is unlikely to be the issue.

  13. art malernee dvm says:

    Hi Guys, can someone tell me why I can’t buy health mouth in Australia?

    better regulatory control of medications ? Remember the first study showing a positive result is usually a false positive but I’m ready to add the stuff to my diet coke if proven safe and effective.

  14. margaret vernon says:

    Thank you for this wonderful site, and all the great comments and reflections on Healthy Mouth. I am amazed that – wow – 5 years later and the jury is still out an the product!
    I was thinking of getting it (Canada) as my cat won’t let me brush, and has diabetes as well as an ongoing upper respiratory infection defying all interventions to date that renders him not suitable for anesthesia. However, the cost was prohibitive so I decided to do a bit more research to see if the price might be worth it. Given the mixed perceptions, and all the thoughtfulness that has gone into all the responses on both sides – I slagged out the emotional overtones and tried to stay focussed on the factual aspects – I have decided to err on the side of caution (not wanting to complicate my cat’s already complicated health – after all he has survived diabetes for 5 years – now 12 years old, and being a stray that I took in off the street).
    Kudos to everyone – this was the best site I found for reviewing the product. I shall keep checking to see if there are any useful updates. Also, thanks for additional questions regarding sidebar isses for addressing pet health – I found them interesting and useful. If anyone has thoughts on respiratory infections and feels this is an appropriate venue for discussion, would love to hear back.
    Thanks to SkepVet for making the site possible.

  15. skeptvet says:

    Thanks for the feedback. I’m always happy to hear that my work is useful! 🙂

  16. Ed Ruff says:

    I have a 11 year old Yorkie Mix that has had normal blood panels her whole life (I have them done yearly). On the last one, my vet was concerned on some slightly elevated levels, so a urine sample was taken and he informed me that her PH is very high. the only thing that has changed in her life is I started her on Healthy Mouth about 2 months prior. Now I am concerned that the Healthy Mouth caused this. I am in the process of investigating this myself. Probably will take her off the Healthy Mouth for a period and check her PH again. My vet is going to ask the manufacturer on this, but I am skeptical of their answer…………………….Research in progress………….??????

  17. skeptvet says:

    I’m not aware of reports that HealthMouth changes urine pH, but it’s certainly possible. However, the urine pH also varies naturally throughout the day, so a a single reading doesn’t tell us much, so I think checking it several times before we get concerned makes sense.

  18. Harry Brooks says:

    Thanks for this report skeptvet. The product is now being sold by Vets in Australia and recommended after my 10+ year old pedigree Pembroke Corgi had plaque removal. Apart from querying the ingredients, the directions are confusing.

    I quote ‘Add 5ml (1 teaspoon) to 1 litre of water or 2ml (4 teaspoons) of concentrate to 4 litres of water.’ Surely if 5ml is 1 teaspoon, they have the directions wrong as 4 teaspoons should read 20ml?

    With a product described as a ‘concentrate’ more care needed. The most disappointing non-publications of per cent ingredients is ‘purified water’ is first listed, so it obviously is the main ingredient.

    I would like to know the per cent water in this $70.00+ product.

  19. Ethan says:

    Thank you for this excellent balanced overview of HealthyMouth. Has there been any new research on the product? Also, what are your feelings on Maxi/Guard Oral Cleansing Gel, which is applied to the gums of cats?

  20. skeptvet says:

    I have not seen any clinical studies, and the company does not provide any citations to published data. The product is also not on the list of tested products for the Veterinary Oral Health Council. Therefore, it doesn’t look like there is any reliable information to support health claims for the product.

  21. Ethan says:

    What are your feelings on Maxi/Guard Oral Cleansing Gel, which is applied to the gums of cats to reduce oral bacteria? Anectodally my family has seen clear improvements in health and overall energy level within just 3 days after applying it, so it does seem to benefit oral health. We have no affiliation with the product or the manufacturer.

  22. Ethan says:

    It’s surprising that HealthyMouth received Veterinary Oral Health Council approval when there aren’t any clinical studies, the product is not on the list of VOHC tested products and the company provides no citations to published data. So on what basis did the Veterinary Oral Health Council provide a seal of approval?

  23. skeptvet says:

    HealthyMouth did perform a clinical trial according to the VOHC guidelines. That is the only way to get the approval.

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