The non-probiotic half of an oral probiotic label, ingredient by ingredient
When people read a probiotic label they read the bacteria and stop. That is half the formula. The other half is what makes the bacteria into a tablet you can chew, and some of those ingredients also do something for you, and some of them do not, and the marketing copy does not distinguish. I spent enough hours at the tablet press to know which is which. ProDentim lists four non-strain ingredients, inulin, malic acid, tricalcium phosphate and peppermint, and they make a good tour of the category.
Inulin: the one with a real job
Inulin is a chain of fructose molecules extracted from chicory root. It is a soluble fiber. Your body cannot digest it, but many bacteria can, which is why it is classified as a prebiotic: food for the microbes rather than for you.
In a gut probiotic, pairing inulin with the strains is standard and sensible. In an oral probiotic the logic carries over: give the strains a food source they can use during the minutes they are dissolving on the tongue, so they have a better chance of establishing. I have not seen a trial testing inulin in the mouth on its own, so I would call this reasonable rather than proven. The Harvard Nutrition Source page on the microbiome covers what prebiotics are and how they relate to probiotics in general terms.
Inulin also has a manufacturing job. It is a bulking agent. A tablet needs enough mass to be pressed and handled, and 3.5 billion bacteria weigh almost nothing. Something has to fill the space. Inulin is a good choice because it is mildly sweet, compresses well, and does something useful rather than nothing. From a formulator's chair, it is the ingredient I would be happiest to see here.
One practical note: inulin in gram quantities causes gas in people sensitive to fructans. The amount in a single small tablet is well below that, by an order of magnitude or more. I would not expect anyone to notice it.
Malic acid: flavor first, whitening claims second
Malic acid is the sour taste in green apples. It is on the FDA's list of substances generally recognized as safe, and it is in thousands of candies, drinks and chewables as an acidulant, which is the formulator's word for "makes it taste tart."
In an oral probiotic tablet, malic acid is there for taste. It cuts the sweetness of the inulin and the mint, and it gives the tablet a little brightness so it does not taste like chalk. That is its job, and it does it well.
The sales copy for this product, and for others in the category, says malic acid "whitens teeth" or "restores natural whiteness," usually with a reference to strawberries. I want to be direct about this. Malic acid is a mild acid, and acids can, in principle, soften surface stain. They can also, in principle, soften enamel. In the amount in one tablet, dissolved over a minute, once a day, it is doing neither in any measurable way. The strawberries-whiten-teeth idea has been tested and the honest reading is that it does not hold up. I would treat the whitening language on any supplement page as marketing, and I would treat malic acid as a flavor. The NIDCR's tooth decay page explains the actual chemistry of enamel losing and regaining minerals, and it has nothing to do with fruit acid.
Tricalcium phosphate: half mineral, half machine
This is the ingredient where my press experience is most relevant. Tricalcium phosphate, TCP on a batch record, is a calcium salt. It is used in supplements for two reasons that have nothing to do with each other.
The first is as a source of calcium and phosphate. Both minerals are what enamel is made of, and some toothpastes include a form of calcium phosphate on the theory that having the ions near the tooth surface helps the natural repair cycle. That is a defensible reason to include it in an oral product, and the sales page leans on it.
The second reason is that TCP is an anticaking and flow agent. Powders that are sticky or electrostatic clump in the hopper and jam the press. A small percentage of TCP keeps the blend flowing so that every tablet gets the same fill weight. On most formulas that crossed my desk, TCP was in the "other ingredients" list for exactly this reason, and nobody was claiming it did anything for the customer.
Here, it is presented as an active. Both readings are legitimate. The amount is not disclosed on the page, so I cannot tell you whether there is enough to matter as a mineral or only enough to matter as a flow agent. My guess, from the category, is the latter, with the former as a bonus. The ProDentim tablet would not be worse without it, and it would be harder to manufacture.
Peppermint: the first thirty seconds
Peppermint oil or peppermint flavor is in nearly every breath product on earth, and the reason is simple. It smells like clean. Menthol produces a cooling sensation that people read as freshness. It covers whatever else is going on for a short while.
The NCCIH's page on peppermint oil summarizes the evidence, which is reasonably good for some digestive complaints and thin for most other uses. It does not treat the cause of bad breath, and the amount in a chewable is a flavor dose, not a therapeutic one. In this formula peppermint is doing two things: making the tablet pleasant, and making the first half minute after you chew it smell minty. The strains are the mechanism, if there is one. The peppermint is the handshake.
I do not mind that at all. A tablet nobody wants to chew is a tablet nobody takes. Flavor is part of compliance. I only mind when the copy says the peppermint is what "removes bad breath," because it is not.
Putting the half back together
| Ingredient | Job for you | Job for the tablet | My read |
|---|---|---|---|
| Inulin | Prebiotic fiber for the strains | Bulking agent, sweetness | Useful on both counts |
| Malic acid | None meaningful | Tart flavor | A flavor; ignore the whitening claim |
| Tricalcium phosphate | Calcium and phosphate ions, in some amount | Flow agent, anticaking | Mostly for the press, possibly a minor bonus |
| Peppermint | Short-lived freshness | Flavor, palatability | Fine, as long as nobody calls it the mechanism |
The honest version of this formula, if I were writing the panel, would list three strains with their codes and CFU, then inulin as a prebiotic, then malic acid, tricalcium phosphate and peppermint under "other ingredients." That is where they belong, and it is how most of the industry would list them. Presenting them as seven co-equal actives is a choice the marketing side made, and it is the kind of choice I used to push back on and usually lose.
None of that makes the product bad. The support ingredients are safe, common and sensible. It makes the page louder than the bottle, and the bottle is what you are buying. If you want to see ProDentim's ingredient list as the company presents it, it is on the official page with their descriptions. Now you have mine next to it.