Nathan and Sons Review: Does Underbrush Gum Really Work?

Nathan and Sons review: the short answer

Underbrush sits in an unusually persuasive product category. It looks like ordinary gum, yet its ingredient panel reads more like an oral-care formula: xylitol, a chicle base, mastic gum, nano- and micro-hydroxyapatite, calcium carbonate, magnesium carbonate and zinc gluconate.

That naturally raises two questions: does Underbrush gum work, and is Underbrush gum legit?
The balanced answer is yes—with boundaries. Nathan & Sons is a real US business selling a real product, and several parts of the formula make sense. Chewing sugar-free gum increases saliva flow, which helps neutralize plaque acids and supports the mouth’s natural remineralization environment. The American Dental Association specifically notes that sugar-free chewing gum can increase saliva, reduce plaque acid and contribute to cavity prevention when used alongside normal oral hygiene. It is not a replacement for brushing and flossing.

What we did not find is an independent, peer-reviewed clinical trial of the complete Underbrush formula. Evidence for xylitol or hydroxyapatite as individual ingredients cannot automatically prove every marketing claim made for this particular gum. That distinction matters, especially if you arrived hoping to reverse a visible cavity. This Nathan and Sons review examines the formula, taste and texture patterns reported by customers, price, purchase terms, alternatives, and the claims that hold up best.

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What is Nathan & Sons Underbrush Gum?

Nathan & Sons, LLC is the company behind Underbrush Remineralizing Gum. Its central pitch is straightforward: replace conventional synthetic gum base with chicle and combine sugar-free chewing with ingredients associated with oral care.
The product is made in the United States with globally sourced ingredients, according to the company. At the time of this review, the official store offered Mastic Mint, Berry, Cinna-Mastic, Tropic Twist and a variety pack, in two-, four- and eight-pack bundles. The product page also advertised a 30-day satisfaction guarantee and free US shipping on orders over $50.

Underbrush is aimed at people who already like chewing gum, particularly after food or coffee, but dislike sugar, aspartame, sucralose or petroleum-derived gum bases. It may also appeal to shoppers interested in fluoride-free hydroxyapatite products. “Fluoride-free,” however, should not be confused with “proved superior to fluoride.” The ADA says fluoride strengthens teeth, helps prevent decay and remineralizes enamel in the earliest stage of decay; ADA-accepted anticavity toothpaste must contain fluoride. The practical benefit is convenience. Most people will not brush at a restaurant, in the car or immediately after lunch at work. A compact pack of sugar-free gum is much easier to use in those moments.

Key features and ingredients

Xylitol and erythritol instead of sugar

Underbrush uses xylitol and erythritol for sweetness. Oral bacteria cannot process xylitol in the same way they process ordinary sugar, and gum chewing stimulates saliva. The ADA’s caries-management guidance says xylitol gum can promote salivary flow and remineralization and is not metabolized by cavity-causing bacteria. 

That does not make every xylitol claim settled science. The American Academy of Pediatric Dentistry has described results across xylitol studies as variable and notes that doses and frequencies used in some trials can be unrealistic. Sugar alcohols may also cause bloating or diarrhea in sensitive people, particularly when consumed in larger amounts. 
One essential safety point: xylitol is extremely dangerous to dogs. Keep every pack, discarded piece and handbag containing Underbrush securely away from pets.

Nano- and micro-hydroxyapatite

Hydroxyapatite is a calcium-phosphate mineral closely related to the mineral component of teeth. It is increasingly used in sensitivity and enamel-care toothpastes. A 2025 systematic review of 15 clinical studies found evidence supporting hydroxyapatite toothpaste for remineralization and dentin hypersensitivity, while also calling for stronger standardization and longer-term research.  There is also a small clinical study involving chewing gum containing calcium hydroxyapatite that reported reduced dentin hypersensitivity compared with control gum. But that study was not an Underbrush trial, so it should be treated as ingredient-level support, not proof of Underbrush’s effectiveness. (PubMed study) In plain English, hydroxyapatite makes the formula more interesting than standard mint gum. It does not justify claims that chewing can fill holes, restore lost enamel thickness or cure active decay.

Chicle gum base and botanical gums

Most chewing-gum labels simply say “gum base,” which may include synthetic materials. Underbrush lists chicle, candelilla wax and citric acid in its base, plus mastic, spruce, acacia and myrrh gums. The natural base creates a different chew. It can begin firm, soften with warmth and retain a more resinous texture than conventional gum. Buyers who want a plastic-free formula may see that as the main reason to pay more. Buyers accustomed to a very soft, highly flavored pellet may need an adjustment period. Mastic and myrrh have long histories of traditional oral use, but “traditional” is not equivalent to proven treatment. Here, they are best viewed as supporting botanical ingredients that contribute taste, texture and product positioning.

Added mineral salts and zinc

Calcium carbonate, magnesium carbonate, calcium bentonite clay and zinc gluconate round out the formula. Calcium-containing ingredients fit the mineral-support concept, while zinc appears in some breath and plaque-control products. The limitation is dose transparency. A list of helpful-sounding minerals does not tell readers how much reaches the tooth surface, how long it remains available or whether that amount produces a clinically meaningful result. Without finished-product testing, these ingredients improve the rationale more than they prove the outcome.

Free-from positioning and flavor range

Nathan & Sons says Underbrush contains no sugar, gluten, aspartame, sucralose, plastic, PFAS or parabens. That is relevant to ingredient-conscious shoppers, although “free from” is not the same as medically better for every person. The flavor range is broader than many niche natural gums. Mastic Mint is the obvious starting point for traditional fresh-breath use. Berry and Tropic Twist suit shoppers who dislike mint, while Cinna-Mastic offers a warmer option.

First impressions: packaging, setup and everyday usability

There is essentially no setup. Open the package, chew one or two pieces after a meal, and dispose of the gum responsibly. That simplicity is Underbrush’s strongest conversion advantage: it does not ask buyers to add another complicated device or lengthy ritual. The packaging presents Underbrush as premium oral care rather than checkout-counter candy. That supports the price psychologically, but it also raises expectations. Shoppers paying this much may expect powerful flavor and an immediately polished feeling. The natural chicle base is the first noticeable difference. Reports across marketplace and independent reviews describe a firm initial bite that settles into an elastic chew. Some enjoy the substantial texture; others compare it with wax or putty. This is a preference issue, not necessarily a quality defect.

Flavor duration is similarly polarizing. Some buyers appreciate a clean, light taste that avoids artificial sweetness. Others say the flavor fades within minutes, even though the gum remains chewable. Anyone choosing Underbrush primarily for a long, intense mint blast should adjust expectations.

Performance and real-world experience

What it does well

The most predictable result is increased saliva and a cleaner-feeling mouth after meals. That benefit comes from chewing itself, enhanced by the absence of fermentable sugar. For dry-mouth comfort, post-coffee freshness or getting food particles moving when brushing is not convenient, the format is genuinely practical.

The chew also lasts after the flavor quiets down. People who enjoy a restrained taste may prefer this to conventional gum that starts aggressively sweet. Because the base is substantial, one or two pieces can feel like a purposeful chewing session rather than a quick breath mint.

Underbrush’s formula is differentiated. PUR and Spry provide accessible xylitol gum, and Simply Gum offers chicle, but Underbrush combines a natural base, xylitol and hydroxyapatite in one product. That combination is the best argument for buying it.

Where expectations need correcting

“Remineralization” is often misunderstood. Teeth undergo mineral loss and gain at the microscopic surface level. Saliva, fluoride and other mineral sources can help early weakened enamel regain mineral under suitable conditions. Once decay has created a physical cavity, gum cannot rebuild the missing structure. A dentist needs to assess it.

Results such as whiter-looking teeth, less sensitivity or smoother surfaces are subjective and may vary. Relief from sensitivity also should not be used to mask a cracked tooth, decay or gum recession. Persistent symptoms warrant an examination.

The product page presents broad reported outcomes, including plaque removal, whitening and gum-health improvements. Those are company claims and customer-reported experiences—not the same as independently verified clinical endpoints. Our rating reflects that gap.

Texture, dental work and tolerance

Gum is not ideal for everyone. People with braces, temporomandibular joint pain, chewing restrictions, loose restorations or extensive dental work should ask their dentist before using a firm gum. A few online comments mention sticking or an awkward texture, though anecdotes cannot establish how common this is.

Xylitol and erythritol can upset digestion when swallowed in meaningful quantities. Most users chewing moderate amounts may not notice this, but sensitive buyers should begin slowly and stop if symptoms occur.

Pricing and value analysis

At our September 2, 2026 check, the official product page displayed a $29.99 starting sale price, with two-, four- and eight-pack options. Search results also showed a lower subscription price, but the checkout price, bundle configuration and discount can change. Confirm the total and renewal interval before purchasing. (Nathan & Sons) This is premium gum. The value equation depends less on whether it beats supermarket gum on flavor and more on whether you specifically want all three of its differentiators: a chicle base, sugar-free xylitol sweetening and added hydroxyapatite/minerals.

If your only requirement is sugar-free chewing after meals, PUR or Spry will generally cost less. If the priority is natural chicle and simple ingredients, Simply Gum is a closer philosophical alternative. Underbrush earns its premium when the combined formula matters and you will use it consistently. Subscription savings can improve the price, but recurring oral-care purchases are easy to forget. Nathan & Sons says monthly subscriptions auto-ship at the beginning of each month. Review the cancellation method and renewal terms before enrolling. The company states that orders usually leave within one to three business days and offers a 30-day return policy; buyer feedback indicates that actual delivery experiences have varied. (Nathan & Sons FAQ)

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Nathan and Sons gum reviews: pros and cons

Who should buy Underbrush Gum?

Underbrush is best for adults who already chew gum frequently and want that habit to do more than freshen breath. It is particularly appealing if you avoid artificial sweeteners, care about a plastic-free chicle base, and are curious about hydroxyapatite oral care. It can also make sense for people seeking an after-meal option when brushing is impractical. The strongest routine is still fluoride toothpaste twice daily, interdental cleaning and regular dental care; Underbrush can sit between those steps.

Who should avoid it?

Skip Underbrush if you dislike firm natural gum, want a powerful long-lasting candy-like flavor, or simply need inexpensive xylitol gum. The mineral blend will not matter enough to justify the premium for every shopper. It is also a poor fit for anyone treating gum as a substitute for oral hygiene. If you have tooth pain, a visible hole, swelling, persistent bleeding, a broken tooth or worsening sensitivity, buy time with a dental appointment—not a multipack. Households with dogs must be especially careful. Xylitol poisoning can be life-threatening, so storage and disposal need to be secure. Parents should also follow age guidance and consult a pediatric dentist for children who might swallow gum or have specific dental needs.

Customer feedback summary

Customer feedback is mixed, and the source matters. The official product page naturally skews positive. Etsy reviews for the official shop include praise for the natural ingredients, substantial chew and cleaner mouthfeel, alongside recurring criticism that the flavor fades quickly. (Official Nathan & Sons Etsy shop) Trustpilot tells a more negative story. At our check, the unclaimed profile showed 14 reviews and a 2.7/5 rating, with 57% at one star. Complaints focused heavily on delayed deliveries and customer service, while at least one reviewer said the gum itself was enjoyable but overhyped. Trustpilot explicitly notes that the company had not invited reviews and that the small set may not be representative. (Nathan & Sons on Trustpilot)

The fairest conclusion is not that every order will go badly or that every health testimonial is true. It is that product enjoyment depends on texture and flavor expectations, while fulfillment deserves monitoring. Use a payment method with normal purchase protections, retain order confirmations and contact support promptly if tracking stalls. We found no basis to present individual sensitivity, whitening or cavity stories as typical results. Personal testimonials can flag patterns; they cannot establish medical efficacy.

Underbrush vs competitors

Underbrush is not automatically “better” than every competitor. It is more specialized. PUR or Spry is the sensible choice when xylitol and affordability matter most. Simply Gum is attractive when natural chicle is the priority. Underbrush wins only for buyers who value the specific overlap of natural base, xylitol and mineral ingredients.

Frequently asked questions

Is Underbrush Gum legit?
Yes. Underbrush is a real product sold by Nathan & Sons, LLC, with a disclosed ingredient list and stated return policy. “Legit” does not mean every advertised benefit has been independently proved. The most defensible benefits come from sugar-free chewing and saliva stimulation; claims about the complete formula need more direct clinical evidence.

Does Underbrush Gum work?
It should work as sugar-free gum: chewing increases saliva, freshens the mouth and can help neutralize acids after eating. Its hydroxyapatite and mineral blend is scientifically plausible, but we found no independent clinical trial showing that Underbrush itself reverses decay or produces all advertised outcomes.

Can Underbrush remineralizing gum heal cavities?
No gum can refill a physical cavity or regrow missing enamel. Early microscopic demineralization may be remineralized under the right conditions, but established decay needs professional assessment. Do not delay dental treatment.

Does Underbrush replace toothpaste?
No. The ADA recommends brushing twice daily with fluoride toothpaste and cleaning between the teeth every day. Underbrush is best treated as an optional after-meal addition.

What is in Nathan and Sons Gum?
The Mastic Mint ingredient list includes xylitol, chicle gum base, erythritol, mastic, spruce, acacia and myrrh gums, flavor, nano- and micro-hydroxyapatite, calcium carbonate, bentonite clay, magnesium carbonate, zinc gluconate and a terpene blend. Flavor-specific formulas may vary, so check the current label.

How long does Underbrush flavor last?
Feedback varies. Some buyers like the light, clean taste; others say the strongest flavor fades within a few minutes or well before the chew ends. Expect a subtler experience than intensely flavored conventional gum.

Is nano-hydroxyapatite safe?
Hydroxyapatite is used in oral-care products and has a growing evidence base, particularly in toothpaste. Individual needs differ, and nanomaterial questions are reasonable. Check the formula with your dentist if pregnant, managing a medical condition or choosing products for a child.

Is Underbrush safe for dogs?
No. Underbrush contains xylitol, which is highly toxic to dogs. Keep unopened packs, used gum and waste bins completely inaccessible to pets. Contact a veterinarian or animal poison service immediately after suspected ingestion.

Can Underbrush cause stomach problems?
It can. Xylitol and erythritol are sugar alcohols, and higher intake may cause gas, cramping or diarrhea. Start with a small amount and stop if discomfort occurs.

Is Nathan and Sons Gum worth the price?
It can be worth it if you want the combined chicle, xylitol and hydroxyapatite formula and enjoy chewing it consistently. It is poor value if you only need inexpensive sugar-free gum or expect it to replace treatment.

What is the Nathan & Sons return policy?
The company states that customers have 30 days after receiving an item to request a return and should contact support for instructions. Confirm eligibility, return costs and exclusions on the current policy before ordering.

Where should I buy Underbrush Gum?
Buying from Nathan & Sons’ official site or its clearly identified official storefront reduces the risk of old or imitation stock. Check the seller, packaging and seal, especially on third-party marketplaces.

Final verdict: is Nathan & Sons Underbrush worth it?

Underbrush is one of the more thoughtfully differentiated gums we have reviewed. It converts an easy, familiar behavior—chewing after meals—into a potentially useful complement to oral care. Xylitol, saliva stimulation and a sugar-free formula provide the strongest foundation. The chicle base and hydroxyapatite make it more distinctive than typical supermarket gum. The marketing still runs ahead of the product-specific evidence. Ingredient research is not a clinical trial of Underbrush, customer testimonials do not prove remineralization, and a gum cannot repair cavities. Add the premium price, divisive texture, short-flavor complaints and a small but concerning cluster of delivery complaints, and this is not an automatic recommendation.

Best for: ingredient-conscious adults who enjoy natural gum and want a convenient after-meal supplement. Who should skip it: value shoppers, long-lasting-flavor seekers, people who cannot safely chew gum, and anyone looking for a treatment for active dental disease. Overall value: good for the right routine, average if judged as ordinary gum.

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