Underbrush Remineralizing Gum

Most conventional sugar-free gums are designed to do two things: freshen breath and stimulate saliva flow. 

Underbrush is formulated around a different goal — it pairs the saliva-stimulating benefit common to all chewing gum with a set of minerals and botanicals that have been studied in oral care research, including hydroxyapatite (in nano and micro particle sizes) and the sugar alcohol xylitol. 

Chewing keeps these ingredients in contact with the teeth and oral environment for an extended window, typically when you're away from a toothbrush. 

The functional chewing gum category has grown quickly for exactly this reason — consumers increasingly want products that fit into an oral care routine rather than just mask odor. 

Underbrush is built to complement brushing and flossing between meals, not to replace them. 

Learn more about what makes natural chewing gum different.

Every Underbrush flavor shares the same foundation: a chicle gum base (chicle, candelilla wax, citric acid), hydroxyapatite in both nano and micro particle sizes — a compound chemically similar to the primary mineral in tooth enamel — and a set of natural resins long used in oral care traditions, including mastic, spruce, myrrh, and acacia gum. 

All flavors are sweetened with sugar alcohols rather than artificial sweeteners. 

The flavors differ in their mineral and flavor profiles: 

Mastic Mint carries the fullest mineral system, with hydroxyapatite plus calcium carbonate, magnesium carbonate, and zinc gluconate, finished with a natural mint terpene blend (menthone, carvone, cineol); 

Berry includes the same broader mineral set along with real fruit powders (blackberry, raspberry, strawberry, dragon fruit), natural and organic flavors, and stevia extract; 

Cinna Mastic features hydroxyapatite, Ceylon cinnamon — the lower-coumarin "true" cinnamon — a warm spice terpene blend (eugenol, cinnamaldehyde, humulene), and stevia extract. 

Because formulations differ by variety, always check the full ingredient list on the specific product you're buying.

Yes — there is a growing body of published, peer-reviewed research on both xylitol and nano-hydroxyapatite in oral care contexts. 

A 2025 narrative review published in the journal Biomimetics reviewed multiple studies evaluating hydroxyapatite in oral care applications and concluded that hydroxyapatite shows promise as a biomimetic ingredient for supporting enamel-focused oral care. 

It's worth being transparent about the limits of this evidence: much of the existing research has been conducted on toothpastes and gels rather than chewing gum specifically, and product-specific clinical trials on nano-hydroxyapatite gum remain limited. 

Chewing may provide prolonged ingredient contact with the oral environment compared with shorter-duration oral care products, although research on hydroxyapatite chewing gum specifically remains limited. Individual results may vary, and this product is not intended to diagnose, treat, cure, or prevent any disease. 

These statements have not been evaluated by the U.S. Food and Drug Administration. We encourage you to consult your dentist or healthcare provider with any specific oral health concerns. 

For further reading, see whether remineralizing gum is legit.

For the best experience, chew each piece for 15 to 20 minutes after meals or as desired throughout the day — this is roughly the window in which most chewing gum delivers its saliva-stimulating benefit and keeps the formulation in contact with the oral environment. 

For hygiene purposes, we recommend replacing each piece every 48–72 hours if you set it aside between uses. 

As with all oral care habits, consistency over time matters more than any single session. 

Chewing after meals, when food particles and acids are most present in the mouth, is a practical time to use it. 

Learn more about chewable mastic gum.

No. Underbrush is designed to complement — not replace — regular brushing, flossing, and professional dental care. 

Think of it as a between-meal addition to an existing routine, especially useful in situations where brushing isn't immediately possible, such as after lunch at work or while traveling. 

No chewing gum is a substitute for the mechanical cleaning that a toothbrush and floss provide, and none should be treated as one. 

Always follow the oral hygiene recommendations of your dentist. 

You may also be interested in natural approaches to tooth sensitivity.

Yes. Nathan & Sons gum is formulated without gluten, soy, dairy, artificial flavors, artificial colors, or artificial sweeteners. It's sweetened with sugar alcohols — xylitol and erythritol — and the Berry and Cinna Mastic flavors also include stevia extract, a naturally derived sweetener. 

Formulations and individual sensitivities vary, so anyone with a known allergy or sensitivity should always review the full ingredient list on the specific product label before use. 

The complete, current ingredient declaration is printed on the packaging and is also available on our official product listings.

Underbrush is built on a chicle gum base — a natural, tree-sap-derived base (chicle, candelilla wax, and citric acid) rather than the synthetic plastic-based polymers found in most conventional gums. 

Chicle is the traditional chewing gum base harvested from the sapodilla tree, used long before petroleum-based gum bases became the industry standard. 

The packaging is designed to be minimal and recyclable. 

We strive to source ingredients responsibly and continually evaluate our sourcing practices, and we encourage customers to recycle in accordance with local guidelines.

Underbrush comes in three flavors built from natural sources rather than artificial enhancers. 

Mastic Mint offers a fresh, clean taste drawn from mastic gum and a natural terpene blend (menthone, carvone, cineol). 

Berry delivers a fruit-forward profile from real fruit powders — blackberry, raspberry, strawberry, and dragon fruit — alongside natural and organic flavors. 

Cinna Mastic is a warm, spiced flavor built on Ceylon cinnamon and a terpene blend of eugenol, cinnamaldehyde, and humulene. 

One honest tradeoff of natural flavoring is duration: without synthetic flavor boosters, the taste may fade somewhat sooner than conventional gum. 

Some users report that the clean, fresh mouthfeel that remains after chewing — distinct from the lingering artificial sweetness of mainstream gum — is one of the qualities they appreciate most. 

Learn more about how natural chewing gum gets its flavor.

Underbrush is positioned as a premium oral care product, and the price reflects two things: a premium ingredient formulation — including hydroxyapatite, botanical resins, and, depending on the flavor, additional minerals and real fruit powders — and a natural, plastic-free chicle base that costs more to produce than conventional gum bases. 

It's best understood not as a one-to-one replacement for a pack of drugstore gum, but as a daily oral care addition that fits conveniently into your routine. 

Each piece is designed for a long-lasting chew, allowing users who choose to do so to reuse a piece during a chewing session. 

As with any wellness product, we encourage you to evaluate it against your individual oral health goals and in consultation with your dental provider. 

See how Underbrush compares to other options in our 2026 US guide.

The ingredients used in Underbrush are commonly used in food, oral care, and consumer products, and the formula is sugar-free and free from common allergens. 

Individuals who are pregnant, breastfeeding, have underlying health conditions, or have concerns about any ingredient should consult a qualified healthcare professional before use. 

For young children, parental supervision is recommended, and we advise following the guidance of a pediatric dentist. 

One important note for pet owners: xylitol is safe for humans but is toxic to dogs, so keep this and any xylitol-containing product away from pets. 

Learn more about whether nano-hydroxyapatite is safe.