NanoChew vs Underbrush: Which Remineralizing Gum Wins?

Underbrush has one of the most committed followings in this category, and it earned it: natural resins instead of synthetic gum base, real minerals instead of just flavor, a founder story people actually know. NanoChew was built on the same convictions.

So the question isn't which brand is serious. Both are. The question is what's in each piece, how long a purchase lasts, and what a year of daily chewing costs. This article covers the science first, then the head-to-head, with every claim sourced.

Last updated: September 2026 · Ingredient and price data confirmed from current listings, September 2026 · Research sourced from peer-reviewed literature

In this article

1. What happens to your enamel after you eat
2. Nano-hydroxyapatite, explained
3. What the clinical evidence shows
4. At a glance
5. The shared foundation
6. Five resins vs two
7. Propolis: the biggest formula gap
8. NanoChew's other additions
9. Formula depth, side by side
10. Pack size and value
11. Dosing: 1–2 pieces or 2–3?
12. Where to buy each one
13. The verdict
14. FAQ
15. Sources

What happens to your enamel after you eat

Dentists chart it as the Stephan curve, and it's the reason this entire product category exists.

Eat something with sugars or starches and plaque bacteria ferment it into acid within minutes. The pH at the tooth surface falls below roughly 5.5, the critical threshold where enamel begins dissolving, and calcium and phosphate start leaving your teeth. Saliva then buffers the acid and carries minerals back in. That recovery usually takes 30 to 60 minutes.

Acidic drinks skip the bacterial step. In a study published in the Journal of the American Dental Association, researchers measured 380 beverages sold in US stores and found 93% had a pH below 4.0, squarely in the erosive range. Sugar-free soda counts. So do sports drinks, citrus juice and wine.

Most people run that cycle three to six times a day and brush for two minutes of it, usually at times that don't coincide with any of them.

Chewing changes the recovery half of the curve. Resting saliva flow is about 0.3–0.4 mL per minute; chewing gum base alone raises it 10 to 12 times, and stimulated saliva carries more calcium, phosphate and hydroxide, the exact ions enamel is built from. That's why the American Dental Association states chewing sugarless gum for 20 minutes after meals can help prevent tooth decay.

A remineralizing gum brings the finished mineral into that window rather than leaving the job to saliva alone.

Nano-hydroxyapatite, explained

Hydroxyapatite is the calcium-phosphate mineral that makes up roughly 97% of your enamel. Natural enamel is assembled from hydroxyapatite crystals around 20–40 nanometres across.

Nano-hydroxyapatite (n-HA) is the same mineral made at that same scale. Size is the whole point: nanoscale particles can settle into the microscopic defects acid leaves behind, while conventional hydroxyapatite particles, many times larger, mostly polish the surface. Researchers call n-HA biomimetic because it isn't a foreign agent. It's what your teeth are made of.

It also isn't experimental. Japan recognized hydroxyapatite as an anti-cavity agent in 1993, and it has been used in daily Japanese oral care ever since. In 2025 the EU's Scientific Committee on Consumer Safety reviewed nano-hydroxyapatite and found no mutagenic, cytotoxic or inflammatory effects, with negligible uptake through the lining of the mouth. Full safety breakdown here.

What the clinical evidence shows

Both gums rest on this literature, so it's worth knowing what it says.

• Cavity prevention. A 2024 systematic review and meta-analysis in the Journal of Dentistry concluded hydroxyapatite is clinically non-inferior to fluoride toothpaste for caries prevention, drawing on randomized trials including an 18-month double-blind study in adults against 1,450 ppm fluoride.
• Remineralization of early lesions. At UT Health San Antonio, 30 adults wore intraoral appliances carrying enamel samples across 28-day phases. Formulas with 5% and 10% nano-hydroxyapatite and an 1,100 ppm fluoride toothpaste all significantly reduced mineral loss and lesion depth, with no significant difference in mineral gain between them.
• Sensitivity. A 2023 meta-analysis of 44 clinical trials found hydroxyapatite beat placebo by nearly 40% and fluoride toothpastes by about 23% for dentin hypersensitivity.
• In gum form. In a double-blind study of 107 people, a sugar-free gum containing hydroxyapatite produced statistically significant improvement in every sensitivity measure after one and two weeks, and significantly outperformed an identical placebo gum.

At a glance

The shared foundation

These two formulas overlap more than almost any other pairing in the category. Here's what they share and why each piece is there.

Nano-hydroxyapatite

Both chose the nano form over conventional hydroxyapatite. That's the correct call, and it's the single decision that separates a real remineralizing gum from a polishing gum.

Xylitol

The most-studied sweetener in preventive dentistry. Cavity-causing Streptococcus mutans takes xylitol up but can't metabolize it, so it drains the bacterium instead of feeding it. A 2025 systematic review in BMC Oral Health found that across the literature, xylitol gum significantly lowered mutans streptococci counts in 12 of 14 studies versus sorbitol gum, reduced plaque accumulation in 6 of 10, and lowered caries occurrence in 3 of 5 trials. Both brands use organic xylitol.

Erythritol

The second polyol in both formulas, notably gentle on digestion, which matters when you're chewing multiple pieces every day.

Mastic gum

The resin of Pistacia lentiscus. A pilot study in the Journal of Periodontology examined the antiplaque effects of mastic chewing gum in the oral cavity, which is unusually direct evidence for a natural gum-base ingredient. Both include it.

Calcium bentonite clay and organic eggshell powder

Both carry both. A 2026 systematic review and meta-analysis in Odontology, covering 17 in vitro studies on extracted human and bovine teeth, found eggshell extract significantly improved enamel microhardness and reduced surface roughness, with the calcium-to-phosphate ratio also improving, and results the authors described as comparable to fluoride varnish and nano-hydroxyapatite. That's laboratory evidence, not clinical, and worth reading as such.

Organic terpene blend

Menthone, carvone and cineol appear in both formulas at under 1%. Cineol (eucalyptol) has documented antimicrobial properties in oral-care research, so the blend does more than flavor.

Seven shared ingredients. The comparison is about what each brand built on top.

Five resins vs two

Underbrush's signature is its base: chicle, mastic, spruce, myrrh and acacia, five natural tree resins blended together. It produces a chew that's genuinely earthy and unlike anything on a drugstore shelf. People who love Underbrush usually mean they love this.

NanoChew uses two: organic chicle for texture and organic mastic for its documented oral-care activity, with coconut oil to keep the chew soft.

The honest assessment of the extra three: spruce, myrrh and acacia all have long traditional histories, and acacia is a common food-grade binder. Their clinical evidence in oral health is thinner than mastic's, and far thinner than propolis's. They shape the chewing experience more than they change what the gum does for your enamel. That's a legitimate formulation choice. It's just a different one from spending that formula space on an active with randomized-trial support.

Propolis: the biggest formula gap

NanoChew contains natural propolis. Underbrush's published ingredient list does not.

Propolis is the resin honeybees make from plant sources to seal and sterilize the hive. It carries hundreds of bioactive compounds, including flavonoids and phenolic acids, with documented antimicrobial, anti-inflammatory and anti-biofilm activity. Over the last decade it has become one of the better-researched natural actives in oral care.

What the research shows:

• A 2025 systematic review and meta-analysis in the Journal of Functional Biomaterials, registered with PROSPERO and covering seven randomized controlled trials, found propolis formulations significantly reduced plaque index scores.
• A 2025 systematic review in BDJ Open assessed propolis for gingivitis and periodontitis across six databases including PubMed, Cochrane CENTRAL and Europe PMC.
• A 2024 randomized controlled trial in BMC Complementary Medicine and Therapies compared propolis with chlorhexidine, the clinical benchmark antiseptic in periodontics, in gingivitis patients.
• A 2025 clinical trial in BMC Oral Health tested propolis in chewing gum form, with participants chewing 20 minutes three times a day after meals while plaque, gingival and papillary bleeding indices were measured.

Why the format matters. A rinse touches your tissue for 30 to 60 seconds. A piece of gum chewed for 20 to 30 minutes keeps its actives working through the entire post-meal window, exactly when acid is attacking enamel and plaque is reorganizing. That's the argument for putting an antibacterial ingredient in gum rather than a bottle, and it's the argument Underbrush's formula can't make.

Underbrush covers antibacterial activity through xylitol and mastic. NanoChew has both of those and propolis on top. See the complete NanoChew ingredient list.

NanoChew's other additions

Coconut oil

Roughly half lauric acid, the fatty acid behind coconut oil's long traditional use in oral care. It also keeps the chew supple, which is why NanoChew stays soft through a full 20–30 minute session instead of stiffening the way mineral-heavy gums often do.

Activated charcoal

Highly porous carbon with a very large surface area, included for the clean mouthfeel it gives during the chew. Underbrush's formula has no equivalent.

Natural calcium

An additional calcium source alongside the nano-hydroxyapatite and eggshell powder. Remineralization runs on calcium and phosphate, and the chewing window is when you want them available.

Formula depth, side by side

Four actives in NanoChew have no counterpart in Underbrush's panel, and one of them, propolis, has randomized-trial evidence behind it, including a trial in gum format.

Try NanoChew — 60 pieces, $29.99 →

Pack size and value

This is where the two diverge most for your wallet, and it's worth working through before you subscribe to anything.

NanoChew: one pouch, 60 pieces, $29.99. That's $0.50 a piece, and at 2–3 pieces a day it covers 20–30 days. One purchase, one month, no tier math.

Underbrush: sold in small boxes, with a 2-pack listed at $29.99 in September 2026. The brand's own FAQ states that one pack lasts about a week, and that a 4-pack is roughly a 30-day supply at two pieces a day. So the $29.99 2-pack is about a two-week supply at a lower daily amount, and a full month means stepping up to the 4-pack.

Two practical consequences:

• Reorder frequency. More frequent reorders mean more chances for a gap, and this product only works if you're consistent. A month in one pouch removes that failure point.
• Annual cost. At three pieces a day, NanoChew runs about $547 a year. Every $0.10 of difference per piece moves that by more than $100, so run the per-piece math on whatever size you're actually buying.

Dosing: 1–2 pieces or 2–3?

The two brands recommend slightly different routines, and the difference is worth understanding.

Underbrush's instructions are to chew one to two pieces after meals, for at least 30 minutes, with longer chewing encouraged. NanoChew's guidance is 2–3 pieces a day, 20–30 minutes each, one after each main meal.

Both sit inside the evidence. The ADA's guidance is 20 minutes of sugar-free gum after meals, and when the ADA evaluated sugar-free gum, the research pattern was 20 minutes of chewing three times a day after meals. The hydroxyapatite gum sensitivity trial and the propolis gum trial used comparable windows.

The practical point: three acid events a day is normal, so a piece after each meal covers all three. That's why NanoChew is built around 2–3 pieces daily, and why a 60-piece pouch is sized to a month at that rate. Full timing guide here.

Where to buy each one

NanoChew is available on nanochewgum.com and Amazon.

Underbrush sells through its own site and Amazon, and the brand maintains a page about counterfeit listings and knock-offs of its product. That's a useful reminder for buyers of any popular oral-care brand: buying from the brand's own store or an official storefront is the safest way to know what you're actually chewing.

The verdict

NanoChew is the stronger daily oral care product for most people. Same seven-ingredient foundation, plus four additional actives led by propolis and its randomized-trial evidence, 60 pieces in a single $29.99 pouch at $0.50 a piece, a full month per purchase, dentist-formulated, and 500+ five-star reviews from people chewing it daily.

If the earthy five-resin chew is what you love about Underbrush, that's a real preference and nothing here replaces it. On formula depth, pack economics and cost per piece, NanoChew wins.

Neither gum is vegan; both contain eggshell powder. And neither replaces brushing, flossing or your dentist.

Start with one pouch — 60 pieces, $29.99 →

FAQ

Is NanoChew better than Underbrush?

For most buyers, yes. Both share nano-hydroxyapatite, xylitol, erythritol, chicle, mastic, bentonite clay and eggshell powder. NanoChew adds propolis, coconut oil, activated charcoal and natural calcium, is dentist-formulated with 500+ five-star reviews, and gives you 60 pieces in one $29.99 pouch. Underbrush's advantage is its five-resin chew and flavor range.

What does propolis add that Underbrush doesn't have?

Antibacterial and antiplaque activity. A 2025 PROSPERO-registered meta-analysis of seven randomized controlled trials found propolis significantly reduced plaque index scores, and a 2025 clinical trial tested it in chewing gum form, chewed 20 minutes three times daily after meals.

Which is cheaper?

NanoChew at $0.50 a piece in a 60-piece pouch. Underbrush's 2-pack was also $29.99 in September 2026, with fewer pieces, and the brand's own guidance puts a 30-day supply at a 4-pack. Do the per-piece math on the size you're buying.

How long does one purchase last?

A NanoChew pouch is 20–30 days at 2–3 pieces daily. Underbrush says one pack lasts about a week and a 4-pack is roughly a month at two pieces a day.

Do they use the same ingredients?

Seven are shared. Underbrush adds spruce, myrrh and acacia to the base. NanoChew adds propolis, coconut oil, activated charcoal and natural calcium.

Which one chews better?

Different, not better. Underbrush is earthy and resin-forward, with mastic mint, berry, cinna-mastic and tropic twist. NanoChew is a single softer spearmint, built with coconut oil to stay pleasant through a full 20–30 minute chew.

How long should I chew each piece?

At least 20 minutes, ideally 20–30. That's the ADA's guidance after meals and the window used in the hydroxyapatite and propolis gum trials.

Is either one vegan?

No. Both contain organic eggshell powder.

Is nano-hydroxyapatite safe?

Yes. The EU's Scientific Committee on Consumer Safety reviewed it in 2025 and found no mutagenic, cytotoxic or inflammatory effects, with negligible uptake through the lining of the mouth. Japan has recognized hydroxyapatite as an anti-cavity agent since 1993.

Can I chew these with braces or TMJ?

Check with your dentist or orthodontist first. The ADA advises people with TMJ disorders to avoid chewing gum.

Does remineralizing gum replace toothpaste?

No. Hydroxyapatite has matched fluoride toothpaste for cavity prevention in trials, but gum covers the hours between brushing rather than replacing it. Full research summary.

How is this different from regular sugar-free gum?

Regular gum gives you the saliva boost and nothing else. Remineralizing gum adds the enamel mineral itself. Full comparison here.

Bottom line

Underbrush deserves its following. It committed to natural resins and real minerals before most of this category existed, and the chew is genuinely its own thing.

But for a habit you're building over months, NanoChew delivers the same foundation plus a propolis-led antibacterial layer, in a pouch that covers a full month for $29.99, at $0.50 a piece, dentist-formulated and backed by 500+ five-star reviews.

Shop NanoChew →

These statements have not been evaluated by the FDA. NanoChew is not intended to diagnose, treat, cure, or prevent any disease and is not a substitute for regular dental care. Competitor details come from that brand's own published listings as of September 2026 and may change.

Sources

1. Underbrush Remineralizing Gum product page and FAQ, nathanandsons.com (price, ingredient list, flavors, usage and supply guidance), checked September 2026.
2. Pawinska M, Paszynska E, Amaechi BT, et al. "Clinical evidence of caries prevention by hydroxyapatite: an updated systematic review and meta-analysis." J Dent. 2024;151. ScienceDirect
3. Paszynska E, Pawinska M, Enax J, et al. "Caries-preventing effect of a hydroxyapatite-toothpaste in adults: an 18-month double-blinded randomized clinical trial." Front Public Health. 2023;11:1199728. doi:10.3389/fpubh.2023.1199728
4. Najibfard K, Ramalingam K, Chedjieu I, Amaechi BT. "Remineralization of early caries by a nano-hydroxyapatite dentifrice." J Clin Dent. 2011;22(5):139–143. PubMed
5. Limeback H, Enax J, Meyer F. "Clinical evidence of biomimetic hydroxyapatite in oral care products for reducing dentin hypersensitivity: an updated systematic review and meta-analysis." Biomimetics. 2023;8(1):23. doi:10.3390/biomimetics8010023
6. Porciani PF, Chazine M, Grandini S. "A clinical study of the efficacy of a new chewing gum containing calcium hydroxyapatite in reducing dentin hypersensitivity." J Clin Dent. 2014;25(2):32–36. PubMed
7. Söderling E, Pienihäkkinen K. "Specific effects of xylitol chewing gum on mutans streptococci levels, plaque accumulation and caries occurrence: a systematic review." BMC Oral Health. 2025;25:1275. doi:10.1186/s12903-025-06602-1
8. Sycińska-Dziarnowska M, Szyszka-Sommerfeld L, Bugajska M, et al. "Propolis as a natural remedy in reducing dental plaque and gingival inflammation: a systematic review and meta-analysis." J Funct Biomater. 2025;16(9):336. doi:10.3390/jfb16090336
9. Khabazian A, Mirhashemi FS, Sadeghi F. "Investigating the effect of propolis-containing chewing gum in comparison with propolis-containing mouthwash on reducing gingival inflammation in patients with gingivitis." BMC Oral Health. 2025;25:231. doi:10.1186/s12903-025-05564-8
10. Ballouk MAH, Altinawi M, Al-Kafri A, et al. "Propolis mouthwashes efficacy in managing gingivitis and periodontitis: a systematic review of the latest findings." BDJ Open. 2025;11:5. doi:10.1038/s41405-025-00294-z
11. Gunjal S, Pateel DGS. "Comparative effectiveness of propolis with chlorhexidine mouthwash on gingivitis: a randomized controlled clinical study." BMC Complement Med Ther. 2024;24:154. doi:10.1186/s12906-024-04456-8
12. "In vitro remineralization effectiveness of eggshell extract on human teeth: a systematic review and meta-analysis." Odontology. 2026;114(3):1057–1068. PubMed
13. Takahashi K, Fukazawa M, Motohira H, et al. "A pilot study on antiplaque effects of mastic chewing gum in the oral cavity." J Periodontol. 2003;74:501–505. PubMed
14. Reddy A, Norris DF, Momeni SS, Waldo B, Ruby JD. "The pH of beverages in the United States." J Am Dent Assoc. 2016;147(4):255–263. PMC
15. American Dental Association. "Chewing Gum." Oral Health Topics. ada.org
16. European Commission, Scientific Committee on Consumer Safety. "Scientific Opinion on Hydroxyapatite (nano), Submission IV." SCCS/1677/25, 2025. European Commission