Underbrush vs Larineco 2026: the honest difference

Comparison

Underbrush vs Larineco 2026: the honest difference

Two nano-hydroxyapatite gums that people search for as a pair, compared on what each brand publishes: the ingredient list, the dose, the particle size, the price, the guarantee against the refund policy, the documents, the citations, and the third-party record. I run Minvelle, a third gum in the same category, so this is a competitor writing about two competitors. The fairness section says what that means. The rest of the page is about them, not about us.

M
Max, Founder of Minvelle
Published September 2026 · Last reviewed: 4 September 2026 · 24 min read
Quick answer

Underbrush or Larineco: which is better?

On the published facts, Underbrush does better on evidence effort, third-party record and company paperwork. Larineco does better on plain-text ingredient disclosure and on posting a dated, specific refund policy. Neither publishes a dose. Underbrush links about 39 citations, of which 3 of the 8 we spot-checked opened to the study claimed; Larineco cites nothing and says "thousands of peer-reviewed studies." Underbrush's Trustpilot page showed 2.7 out of 5 from 14 reviews when we looked on 27 August 2026; Larineco's BBB profile shows an F rating and 190 complaints in three years. Underbrush's storefront promises a 30-day guarantee that its own refund policy does not extend to gum; Larineco's policy is posted and dated, and limits its guarantee to a first purchase per household.

What is in the gum?

Both list nano-hydroxyapatite, xylitol, erythritol and a tree-resin gum base. Neither states a milligram amount for anything, a particle size in nanometers, or a certificate of analysis you can open. Our brand database records the dose as "not disclosed" and documents downloadable as zero for both, as of 4 September 2026. Neither brand, and not ours either, has published a clinical trial on its own finished gum.

The verdict

The quick verdict, criterion by criterion

Here is who does better on each thing we could check, with the single fact that decided it. All of it comes from our brand database, our Underbrush review, our Larineco review and our citation audit, re-read on 4 September 2026. Where neither brand publishes something, the line says so instead of guessing.

  • Ingredient list: tie. Both publish a full list. Neither publishes a quantity for any ingredient.
  • Dose per piece: neither. Our database records "not disclosed" for both.
  • Particle size: neither. Underbrush says "nano and micro"; Larineco says "nano." No nanometer figure from either.
  • Documents you can download: neither. Zero for both in our database.
  • Evidence cited: Underbrush, with a caveat. It cites about 39 studies and 3 of the 8 we checked resolved cleanly. Larineco cites none.
  • Accuracy of what is cited: neither passes. Five of Underbrush's eight spot-checked citations did not open to the record claimed. Larineco has nothing to check.
  • Guarantee that matches the policy: Larineco. Its refund policy is dated and specific. Underbrush's storefront banner and its refund policy say different things about gum.
  • Third-party review record: Underbrush. A 2.7 out of 5 on Trustpilot from 14 reviews is not good, but Larineco's BBB profile shows an F rating and 190 complaints.
  • Company paperwork: Underbrush. A Wyoming LLC with a registered USPTO trademark and one consistent founding story. Larineco is a named New Jersey corporation with three different addresses across its own documents.
  • Price you can compute: Underbrush, narrowly. USD 29.99 one-time and USD 20.99 on subscription are stated plainly. Larineco shows every tier at exactly half a crossed-out anchor, so we did not compute a per-piece price.

If you only want the one-sentence version: Underbrush is the more documented company with the less careful citations; Larineco is the more disclosed ingredient list with the heavier complaint record; and neither tells you how much hydroxyapatite you are chewing.

Comparison table

Underbrush and Larineco, side by side

"As labelled" means what the brand's own page says, not what we assume is inside. Every cell carries the date we looked or points to the page that does. Where a brand publishes nothing, the cell says "not stated." We do not fill blanks.

Criterion Underbrush (Nathan & Sons) Larineco (Larine C Corporation)
Active as labelled Hydroxyapatite, "nano and micro" Nano-hydroxyapatite
Dose per piece disclosed No (database: "not disclosed") No (database: "not disclosed")
Particle size Not stated in nanometers Not stated
Xylitol Yes, first on the mint list, paired with erythritol Yes, second after the active, paired with erythritol
Gum base Chicle, mastic, spruce, plus myrrh and acacia on the full list Chicle, mastic, spruce, myrrh, acacia; bentonite clay and eggshell powder
Pieces per pack Not stated on its own page Not recorded by us
Price as we publish it USD 29.99 one-time, USD 20.99 subscribe; variants USD 20.99 to 79.99 Not computed per piece; e.g. two boxes USD 35.90 crossed out to USD 17.90 under an "Up To 50% Off" banner
Guarantee vs policy Storefront: "30-Day Satisfaction Guarantee." Refund policy: gum is final sale; exchange only via paid add-on 30-day guarantee in writing, first purchase per household only (policy dated 23 Feb 2026)
Documents downloadable 0 0
Citation audit (27 Aug 2026) ~39 linked; 8 checked: 3 clean, 5 misresolve; ~31 unchecked Zero citations; "thousands of peer-reviewed studies" claimed
Third-party record Trustpilot 2.7/5 from 14 reviews (27 Aug 2026); no BBB profile BBB F, 190 complaints in 3 years, 1.89/5 from 97 reviews; no Trustpilot figure in our sources
Legal entity Nathan & Sons LLC, Wyoming; USPTO reg. 7850981 Larine C Corporation, dba Larine; New Jersey law

Data: minvelle.com brand database and the linked review and audit pages, re-read 4 September 2026. Prices are the brands' own list prices on the date of our review and will drift.

Method

How we checked, and what we did not do

This is not a taste test. I have chewed both gums, and my opinion of how they feel in the mouth is worth exactly as much as one Reddit comment, which is why the texture section below quotes Reddit rather than me. It is also not a lab test. We did not send either gum to a laboratory to measure hydroxyapatite, and any page that tells you it did should show you the certificate.

What we did is read. Each brand has a full review on this blog, written on its own and dated: the Underbrush review and the Larineco review. Underbrush also has a company page, on Nathan & Sons, and a page on what Reddit says about it. For each review we captured the product page, the ingredient list, the FAQ, the refund policy and the terms of service on the same date, so that when a storefront and a policy disagree, we can say they disagreed on that day rather than guess that one was updated later.

The evidence check is the citation audit, run on 27 August 2026. It asks two questions of every reference a brand publishes: does the PubMed ID or DOI open at all, and does the record it opens match the authors, journal, year and finding the brand attached to it. A citation that opens to the wrong paper gets recorded as "wrong record" or "wrong authors." A brand that publishes no citations gets recorded as "cites no studies," which is a different finding and we keep the two apart. For this page I re-ran the seven PubMed IDs that appear below through NCBI's own lookup on 4 September 2026 and confirmed each title and first author.

The third-party record comes from where each brand has one. Underbrush has a Trustpilot page and no BBB profile. Larineco has a BBB profile and a ScamPulse listing, and our sources hold no Trustpilot figure for it. We report what each platform lists, with the date, and we do not add the two records together as if they were the same measure.

What we refused to do: estimate a dose from the order of an ingredient list, estimate a piece count a brand does not state, or compute a per-piece price from a crossed-out anchor. Where our comparison chart already carries a computed figure for Underbrush, we show it and say what it rests on. Brands change pages. If either brand publishes a dose, a size or a corrected citation after 4 September 2026, this page is out of date on that point, and I want to hear about it.

Ingredients

The ingredient labels, line by line

This is the section where the two gums look most alike, and the resemblance is real. Both are built on a natural tree-resin base rather than the synthetic polymer base of a supermarket gum. Both sweeten with xylitol and erythritol. Both add calcium bentonite clay and a terpene blend. Both name hydroxyapatite as the mineral active. The differences are in the details, and in one case in what one brand chose to add that the other did not.

Underbrush, as listed

The mint-flavor list quoted on our Nathan & Sons page runs: xylitol, chicle base (chicle, candelilla wax, citric acid), erythritol, mastic gum, spruce gum, acacia gum, mint flavor, myrrh gum, hydroxyapatite (nano and micro), calcium carbonate, calcium bentonite clay, magnesium carbonate, zinc gluconate, terpene blend. Fifteen entries, no quantity for any of them.

Three things stand out. First, xylitol leads the list, ahead of the gum base, which in a descending-order label means it is the largest single ingredient by weight. Second, hydroxyapatite sits ninth, after the mint flavor. On a descending-order label that places it below the flavor by weight, and the page gives no number to say by how much. Third, the phrase "nano and micro" tells you the mineral comes in two size ranges without saying what either range is. Our Underbrush review records the particle size as not stated, and our database records the dose as not disclosed. The list also carries three extra minerals, calcium carbonate, magnesium carbonate and zinc gluconate, that Larineco's list does not.

One detail that our Nathan & Sons review found worth noting: the company's own blog comparison article names a competitor, Enamio, as the "best fit" for "concentration transparency." That is a brand grading itself second on a criterion it does not itself publish a number for. I read it as candor rather than as a problem, but it does confirm from the company's own keyboard that the concentration is not on its page.

Larineco, as listed

Larineco's list, published in plain text on its product page and quoted in our review: nano-hydroxyapatite, xylitol, erythritol, natural gum bases (chicle, mastic, spruce, myrrh, acacia), calcium bentonite clay, eggshell powder, terpene blend (menthone, carvone, cineole). Our review called it an "unusually characterful list," and it is. Five resins in the base is more than most gums bother with, and naming the three terpenes is a level of detail many brands skip.

Here nano-hydroxyapatite leads the list. On a descending-order label that would mean it outweighs the xylitol, which would be unusual for a gum, and the page gives no figure to confirm or deny it. Our review's summary of the numbers is blunt: "every load-bearing number is missing." No particle size, no per-piece dose, no concentration. The database records the same "not disclosed" as for Underbrush.

The ingredient that separates the two lists is eggshell powder. Eggshell is calcium carbonate. Enamel is calcium phosphate, of which hydroxyapatite is the crystalline form. Our Dentagum review drew that distinction for a different brand and it applies here the same way: the eggshell contributes calcium, not hydroxyapatite, and the two should not be read as the same thing. Larineco does not claim they are. It simply lists both, and the reader has to know the difference.

What the two lists share, and what neither says

Xylitol plus erythritol is the sweetener pairing our own gum uses, and I think both brands chose well there. The five-resin base is shared almost entry for entry: chicle, mastic, spruce, myrrh, acacia appear on both lists. Both add calcium bentonite clay. Both add a terpene blend, which Larineco names and Underbrush does not.

And both leave the same blank. There is no milligram of hydroxyapatite per piece on either page. There is no particle size in nanometers on either page. There is no certificate of analysis to download from either. On the question a buyer most wants answered, how much of the active am I getting, the two brands are identical: they do not say. Our label-by-label test of remineralizing gum explains why that single number matters more than the length of the list.

Evidence

The studies each brand cites, and what resolved

This is the section where the two brands differ most, and not in a way that flatters either. One cites a great deal and gets a good share of it wrong. The other cites nothing and says it has thousands.

Underbrush: about 39 citations, 8 checked, 5 misresolve

The Underbrush product page links roughly 39 citations. Our citation audit spot-checked eight of them against PubMed and CrossRef on 27 August 2026. Three opened to the record claimed. Two of those three are worth naming because they are solid hydroxyapatite papers: Najibfard and colleagues' 2011 study in the Journal of Clinical Dentistry on remineralization of early caries by a nano-hydroxyapatite dentifrice, PMID 22403978, and Schlagenhauf and colleagues' 2019 six-month randomized trial of a microcrystalline hydroxyapatite dentifrice, PMID 30701704. Both are toothpaste studies, not gum studies, but they resolve cleanly to what the page says they are.

Five did not resolve. Our audit's categories, with what I re-verified on 4 September 2026:

  • Wrong record. The xylitol citation, attributed to Makinen, carries PMID 25867215. That ID opens to Shi and colleagues, a 2015 paper in the Journal of Clinical Periodontology on non-equilibrium plasma in ligature-induced peri-implantitis. It has nothing to do with xylitol. I confirmed the title and first author through NCBI's lookup.
  • Wrong authors. The mastic-gum citation names "Vukovic AM." The 2006 Archives of Oral Biology paper it appears to point at is by Aksoy, Duran and Koksal. Our audit page carries no PubMed ID for this one, so I could not re-run it and report it as the audit found it.
  • Wrong authors. The calcium-carbonate citation names "Zero DT." The 2003 Caries Research paper it points at is by Cury and colleagues.
  • Real study, wrong attribution. The mint-oil citation points at a real 2024 pilot study in Microorganisms on the effects of mint oils on the human oral microbiome, PMID 39203382, first author Abdelrahman. The Underbrush page attributes it to different, unnamed authors. I confirmed the record on 4 September 2026.
  • Malformed link. The gum-arabic citation places a PMC identifier in a PubMed URL slot, and the link redirects to an unrelated record. No checkable ID survives, so I report it as the audit found it.

About 31 citations on the page were not checked. That is not a finding about them either way. It is a statement of how far the audit got. Five of eight is the sample; what the full 39 would show, nobody on our side knows, and I would rather say that than extrapolate.

What this does and does not mean. A citation that opens to the wrong paper does not prove the claim it was attached to is false. Xylitol's dental literature is large and the page may simply have pasted the wrong ID. But a reader who clicks the link to check the claim is sent somewhere that cannot check it, and on five of eight tries that happened. For a page that leans on its footnotes as hard as Underbrush's does, that is the finding.

Larineco: zero citations, "thousands of peer-reviewed studies"

Larineco's storefront states that the product is "Backed by thousands of peer-reviewed studies." Our review found no citation, footnote or link anywhere on the site. A PubMed search for "larineco" returned zero results on 22 August 2026, which is expected for a brand under two years old and is not itself a mark against it; the mark is the gap between the sentence on the storefront and the absence of a single reference beneath it.

The company's own Terms of Service, captured on the same date, say: "Any research references relate to individual ingredients and may not apply to our specific product formulations." Our review reads that as the company's own statement that the research it alludes to is ingredient-level, not product-level. I think that reading is fair, and I also think the sentence is honest. Ingredient-level research is all any of us in this category have. The difference is that Larineco's storefront does not say so, and its terms do.

Our audit classifies Larineco as a cites-no-studies finding, not a misresolving-citation finding. Those are different failures. Underbrush gave a reader something to check and it often did not check out. Larineco gave a reader nothing to check. Which is worse depends on what you value. I would rather be handed a wrong footnote I can catch than a promise I cannot test, but I can see the other view.

What the hydroxyapatite evidence actually supports

Since neither brand's citations can carry the reader to the literature, here is the shape of it, with PubMed IDs you can open. The strongest single trial for hydroxyapatite in oral care is a toothpaste trial: Paszynska and colleagues, an 18-month randomized controlled trial of 189 adults published in Frontiers in Public Health in 2023, PMID 37533523, which found a hydroxyapatite toothpaste non-inferior to fluoride for caries prevention. The best overview is Wierichs and colleagues, a 2022 systematic review and meta-analysis in Clinical Oral Investigations, PMID 35103837, which found nano-hydroxyapatite comparable to fluoride and called the evidence "not yet conclusive."

For gum specifically, the only peer-reviewed hydroxyapatite gum trial our reviews found is Porciani and colleagues, 2014, in the Journal of Clinical Dentistry, PMID 25122980. It measured dentin hypersensitivity, not cavities, and it did not use either brand's product. Neither Underbrush nor Larineco has a published clinical trial on its own finished gum. Neither do we. Every gum in this category is borrowing toothpaste evidence, and the honest thing to do is say so, which is what this paragraph is for.

Buying

The buying experience: price, guarantee, billing, address

This is the section most people searching "underbrush vs larineco" are really asking about. Not the mineral. The money, and whether they will get it back.

Price

Underbrush is priced plainly. Our review recorded USD 29.99 for a one-time purchase and USD 20.99 on subscribe-and-save on nathanandsons.com, with variant prices from USD 20.99 to USD 79.99 across tiers. What the page does not state is how many pieces are in a box. Reddit commenters count 16 to 18, but that is Reddit, not the brand. Our comparison chart shows about USD 1.14 per piece for Underbrush; Underbrush's own page does not state the piece count that figure rests on, so treat it as our chart's estimate and not as a published number.

Larineco is priced differently, and we deliberately did not compute a per-piece figure. Our review found every tier displayed at exactly half a crossed-out anchor: two boxes shown at USD 35.90 struck through to USD 17.90, for example, under a site-wide "Up To 50% Off" banner. When the "sale" price is the only price anyone is ever asked to pay, dividing it by a piece count tells you nothing stable, so our database records Larineco's per-piece price as "not computed (anchor-priced)." I would rather leave a cell blank than print a number I do not believe.

Guarantee against policy

Underbrush's storefront carries the line "30-Day Satisfaction Guarantee | Fast Shipping + Easy Returns." Its refund policy, on the same domain and captured on the same date, lists "Chewing gum (all flavors)" as final sale. A paid "Package Protection" add-on covers a "Taste Guarantee," and that is an exchange, not a refund. New subscriptions "cannot be canceled within the first 10 days." EU orders get the 14-day cooling-off window that EU law requires, with the usual exclusions for consumables. Our database records Underbrush's guarantee in writing as "No | gum is final sale; guarantee only via a paid add-on." So the banner says one thing and the policy says another, and if you ask for your money back it is the policy that answers.

Larineco's refund policy is dated 23 February 2026 and says what it covers: a 30-day guarantee, first purchase per household only; damaged items replaced rather than refunded; cancellations after processing not refundable. Our database records it as "Yes | 30-day, first purchase per household only." Our review's line on it was: "The policies, however restrictive, are posted, dated and specific; a refund policy that tells you its limits before you buy is better than a vague one that improvises after." That is why Larineco takes this criterion. Its guarantee is narrow, but the storefront and the policy do not contradict each other on refunds the way Underbrush's do.

Where Larineco's pages do contradict each other is on claims rather than refunds. The storefront says "Strengthens & protects enamel with nano-hydroxyapatite," carries a "LOVED BY DENTISTS" badge that names no dentist, and states the product is backed by thousands of studies. The Terms of Service, same capture date, say the products "are cosmetic oral care items... not intended to diagnose, treat, cure, or prevent any disease, medical condition, or dental disorder." That is the standard disclaimer, and Underbrush carries one too. The difference is that our review found Underbrush's official pages "do not overreach," with no whitening claim, while Larineco's storefront makes claims its own terms then walk back.

Subscription and billing, as attributed

Both brands sell on subscription. Both have public complaints about it. The scale differs.

For Underbrush, the record we hold is Trustpilot: 2.7 out of 5 from 14 reviews when we checked on 27 August 2026, with 57 percent one-star and 29 percent five-star. One one-star review from May 2026 describes subscription cancellation as "tricky" and mentions "hidden costs behind what seems like a deal." That is one review, and I am quoting it as one review. Underbrush's refund policy's line that new subscriptions cannot be canceled in the first 10 days is the policy fact that sits behind it.

For Larineco, the record is BBB and ScamPulse. BBB lists an F rating, 1.89 out of 5 across 97 reviews, and 190 complaints in three years, broken down as product 79, delivery 40, service 37, advertising 15 and billing 10. BBB also opened an advertising-substantiation review in March 2025 on two claims, "Improve your oral health in seconds" and "98% Noticed brighter & whiter teeth," and recorded no company response as of late March 2025. ScamPulse lists more than 28 reports, and our review found the recurring theme to be undisclosed subscription enrollment plus charges after cancellation. Two quotes, attributed and dated. Jessica M., 31 May 2026: "...automatically get signed up for a subscription..." A ScamPulse report of 10 August 2026: "I cancelled the subscription... They billed my ATM card for the $54.31 and sent the three packs of gum any way."

Two things I want to be careful about here. First, these are complaints, and complaints are filed by people who had a bad experience; nobody files a BBB report to say a subscription renewed as expected. Second, our review noted the pattern is about billing, not delivery: "the reports generally describe gum that arrives." Larineco ships. The dispute is over what people are charged and when.

One more Larineco item belongs here because it bears on how much weight to give any on-site number. Its product page shows "4.8 (2,847 Reviews)," while each bundle listing shows an identical "(214,887 Reviews)." Our review did the arithmetic: a company whose first domain was registered on 20 September 2024 would need more than 300 new reviews every single day to reach that figure, and BBB's own count is 97. The testimonial carousel attributes four different videos to the same name and photo, "Sarah K." I am not going to tell you what to conclude. I am telling you the numbers do not agree with each other, and that our database marks third-party-verifiable review counts as "No | on-site widget only" for both brands.

Who you are buying from

Underbrush is made by Nathan & Sons LLC, a Wyoming company. The USPTO shows the UNDERBRUSH mark registered on 1 July 2025 under number 7850981, with first use claimed from 1 April 2023, and a pending combined-mark filing that names Nathan Malonson. The Cheyenne, Wyoming suite on the paperwork is a registered-agent address, which is normal for a Wyoming LLC. A press release on EIN Presswire dated 12 May 2025 is datelined Placerville, California and describes the founder, "Nathan Mal," as a former executive chef. Modern Retail reported the company was founded in 2022, went viral on TikTok around Thanksgiving 2023, hard-launched in January 2024, "surpassed $30 million in sales" in 2024, has fought more than 800 knockoffs and has spent more than a million dollars against counterfeiters. The domain nathanandsons.com was created on 21 June 2023 and is WHOIS-shielded. There is no BBB profile, which our review treats as neutral.

Larineco is sold by Larine C Corporation, doing business as Larine, under New Jersey governing law with arbitration in Ocean County, New Jersey. RDAP shows buylarine.com registered on 20 September 2024 and larineco.com on 21 November 2024, so the brand is under two years old. Our review found three different addresses across the company's own paperwork: Point Pleasant Beach, New Jersey, in the terms of service; a Conroe, Texas apartment in SMS boilerplate, which may belong to a vendor; and Rancho Cucamonga, California, at BBB. Our review reports that as a documented inconsistency and not as an accusation, and so do I. Meta's Ad Library showed on the order of a thousand active results for the brand keyword in August 2026, alongside a six-figure social following. Advertising spend measures advertising spend.

Reddit

What Reddit says, from the threads we read

We have a Reddit page for Underbrush and not for Larineco, so this section is one-sided by construction. Everything below is from our Underbrush Reddit page, which read 11 threads. I have nothing comparable on Larineco to set beside it, and I am not going to pretend a search I did not run.

Genuine product. The threads treat Underbrush as a real gum that arrives. The threads asking whether the brand is legitimate turn out, on reading, to be about counterfeits sold through TikTok Shop and copycat storefronts with names like "Softeland" and "Forrest Folk," not about the real brand. One buyer who reordered from the real store after a copycat experience called it a "Totally different experience." This matters for the comparison because the Modern Retail figures on knockoffs and anti-counterfeiting spend are the same story from the company's side.

Texture. The pieces are small and firm. Most commenters chew two or three at once. The chew is "loved by some, called a brick by others." Two users report losing fillings. I include that because it is in the threads, not because I can verify it, and because a dense tree-resin chew is a materials choice with a known trade-off for people with older dental work.

Flavor. Gone in 10 to 60 seconds, according to the threads, with a resin aftertaste. That is consistent with a mint flavor sitting seventh on the ingredient list and with no synthetic flavor carrier.

Dose. No commenter in 11 threads asked how much hydroxyapatite is in a piece. I find that the most interesting finding on the page. The question that decides whether the gum can do anything is the question nobody asks.

Safety. One unresolved thread carries a fear about nano-hydroxyapatite and blood vessels. Our Reddit page traced it to a cell-culture paper outside the scope of oral exposure, and noted that the EU scientific committee's opinion on nano-hydroxyapatite, SCCS/1648/22, covers toothpaste and mouthwash and does not cover gum. That is a gap in the regulatory literature for the whole category, ours included, and not a finding against Underbrush.

Who should pick which

Who should pick Underbrush, who should pick Larineco, and who should pick neither

Pick Underbrush if you want a firm, long-holding resin chew and you are buying from the company on a plain price. USD 20.99 on subscription is priced well for the category, the company has a registered trademark and a trade-press paper trail, and its official pages make no whitening claim. Go in knowing three things: the gum is final sale under the refund policy no matter what the banner says, a new subscription cannot be cancelled in its first 10 days, and about five of every eight citations we checked will not take you to the paper claimed. Buy from nathanandsons.com directly; the Reddit threads about bad experiences are about copycats.

Pick Larineco if the ingredient list is what you are buying, and it is a good one: the five-resin base, the named terpenes, xylitol with erythritol. Its refund policy is narrow but it is dated and it says what it covers. Go in knowing that there is not a single study cited on the site, that the guarantee applies to one purchase per household, that cancellations after processing are not refundable by the policy's own terms, and that BBB and ScamPulse hold a documented pattern of billing complaints. If you subscribe, read the cancellation terms before the first charge, not after.

Pick neither if what you want is a number. Neither brand tells you how many milligrams of hydroxyapatite are in a piece, what size the particles are, or what a batch tested at. If your reason for buying a hydroxyapatite gum over a plain xylitol gum is the hydroxyapatite, then you are paying for an ingredient whose quantity both brands decline to state, and the price difference between these gums and a plain xylitol gum is the price of that unstated ingredient. Our ranking of 14 remineralizing gums sorts the whole category on that criterion, and I will say now that our own gum is at the top of it, so read that page with the same suspicion you are reading this one.

Pick neither, and see a dentist, if you have active decay, a cracked tooth or sensitivity that does not settle. No gum treats those. Both brands' terms say the same, and so do ours.

Fairness

What each brand does well, and our conflict of interest

I sell a competing gum. Minvelle is my company, it makes one product, and that product sits in the same category as the two on this page. There is no version of a competitor comparison where that is not a conflict of interest, and I would rather write it here than have you find it in the footer. Here is what I have done about it, and then here is what each brand deserves credit for.

Every negative fact on this page is attributed to a page, an audit, a registry or a platform, with the date we looked. We used the same categories for both brands: "not disclosed," "wrong record," "cites no studies," "not computed." We did not use verdict words about either company, and if you find one, tell me and it comes out. Brands update pages. When either of these two publishes a dose, corrects a citation, or changes a policy, the relevant line above is wrong until we re-check it. The "Last reviewed" date at the top is the date this page was last true to our knowledge, and this page is accurate as of 4 September 2026 and not necessarily after.

What Underbrush does well

Our Underbrush review put it this way, and I stand behind each line. "Underbrush's chicle, mastic and spruce base gives a firm, substantial chew that a lot of people genuinely prefer." "Underbrush's official pages do not overreach. They make no whitening claim and they carry the standard FDA disclaimer." "At USD 20.99 on subscribe-and-save, Underbrush is priced well... full stop." And on the company: "A Wyoming LLC holding a registered USPTO trademark, a documented founding story, trade-press-reported sales past $30 million in 2024, and a serious, expensive fight against counterfeiters." Our Nathan & Sons page added: "a chicle, mastic, spruce and myrrh chew base is a genuinely characterful materials choice... Whoever wrote this recipe knows the category." It also cited studies at all, which most brands in this category do not, and three of the eight we checked were good ones.

What Larineco does well

From our Larineco review, again verbatim. "Larineco is a real product from a named company... with a disclosed and genuinely interesting ingredient list and marketing running at very large scale. That much checks out." "The ingredient list is disclosed in plain text, which is more than some competitors manage... a materials choice with taste." "Xylitol plus erythritol is exactly the sweetener pairing our own gum uses, chosen for good reasons." "The policies, however restrictive, are posted, dated and specific." "A named legal entity stands behind the store... more accountability scaffolding than anonymous drop-ship storefronts offer." And the complaint record, whatever else it shows, "generally describe[s] gum that arrives."

How to check us the same way

Run the same table on Minvelle and see whether it holds up. Dose: 5.7 mg of nano-hydroxyapatite per piece, 0.30 percent of a 1.9 g piece, on our transparency page. Particle size: rods of 200 nm by 20 to 50 nm, as stated by our supplier. Documents: a safety data sheet and a batch certificate of analysis, downloadable, with the manufacturer's name redacted, and the page says so. Ingredient list: 14 items with per-piece weights. Price: EUR 24.99 for one box of 18 bought once; the subscription is EUR 29.99 for two boxes every four weeks, which works out to EUR 15.00 a box. Guarantee: 30-day refund on unopened boxes, and our policy page says the same. Clinical trial on the finished gum: none, same as both brands above. Trustpilot: claimed profile, two reviews at the time of writing (4 September 2026). If any of those does not match what you find, one of the pages is wrong and I want to know.

If the dose is what you were looking for: Minvelle is a sugar-free gum with 5.7 mg of nano-hydroxyapatite per piece, 18 pieces per box, one piece a day, with the full ingredient list and batch certificate published. Try it with 10% off, or read the full formula first. Unopened boxes carry a 30-day refund.

FAQ

Questions people ask about the pair

Underbrush or Larineco: which is the better gum?

On the facts each brand publishes, checked 4 September 2026, Underbrush does better on evidence effort, third-party record and company paperwork: it links about 39 citations, of which 3 of the 8 we spot-checked resolved cleanly, it holds a registered US trademark, and its Trustpilot page shows 2.7 out of 5 from 14 reviews. Larineco does better on plain-text ingredient disclosure and on posting a dated, specific refund policy, but it cites no studies at all and carries a BBB F rating with 190 complaints in three years. Neither brand publishes a dose per piece, a particle size or a certificate of analysis, so neither can be called better on what is actually in the gum.

Does Underbrush or Larineco publish how much hydroxyapatite is in a piece?

No. As of 4 September 2026 our brand database records the dose as not disclosed for both. Underbrush describes its hydroxyapatite as nano and micro particle sizes with no nanometer figure and no milligram amount. Larineco names nano-hydroxyapatite with no particle size, no per-piece dose and no concentration anywhere on its site. Neither brand publishes a downloadable certificate of analysis or safety data sheet.

Does Underbrush have a money-back guarantee?

The storefront banner reads 30-Day Satisfaction Guarantee, Fast Shipping and Easy Returns. The refund policy on the same domain, captured on the same date, lists chewing gum in all flavors as final sale, with a Taste Guarantee exchange available only through a paid Package Protection add-on. New subscriptions cannot be canceled within the first 10 days. EU orders get a 14-day cooling-off window with consumable exclusions. So the answer depends on which page you read, and the policy page is the one that governs a refund request.

Why do Larineco customers report charges after cancelling?

We do not know why, and we have not tested it ourselves. What we can report is the pattern in the public record: BBB lists 190 complaints in three years, of which 10 are filed under billing and 37 under service, and ScamPulse lists more than 28 reports with a recurring theme of undisclosed subscription enrollment and post-cancellation charges. One ScamPulse report dated 10 August 2026 states that a cancelled subscription was billed 54.31 dollars and three packs of gum were shipped anyway. Larineco's own refund policy, dated 23 February 2026, states that cancellations after processing are not refundable.

Which brand has the more transparent ingredient list?

Both publish a full ingredient list, and neither publishes a quantity for any ingredient. Larineco's list is in plain text on its product page: nano-hydroxyapatite, xylitol, erythritol, a five-resin gum base of chicle, mastic, spruce, myrrh and acacia, calcium bentonite clay, eggshell powder and a terpene blend. Underbrush's mint list runs xylitol, a chicle base, erythritol, mastic, spruce, acacia, mint flavor, myrrh, hydroxyapatite in nano and micro form, calcium carbonate, calcium bentonite clay, magnesium carbonate, zinc gluconate and a terpene blend. On the list itself it is close to a tie. On the numbers behind the list, both are blank.

Do the studies Underbrush cites check out?

Partly. Our citation audit on 27 August 2026 spot-checked 8 of about 39 linked citations on the Underbrush product page against PubMed and CrossRef. Three opened to the record claimed. Five did not: one xylitol citation opens to an unrelated paper on peri-implantitis, two citations name authors who did not write the paper linked, one mint-oil citation points to a real 2024 study but attributes it to different authors, and one gum-arabic link is malformed and redirects to an unrelated record. About 31 citations were not checked. Larineco, by contrast, cites no studies, so there was nothing to check.

Can either gum replace fluoride toothpaste?

No. Neither brand has published a clinical trial on its own finished gum, and the same is true of our gum. The hydroxyapatite evidence that exists is mostly toothpaste: an 18-month randomized trial of 189 adults found a hydroxyapatite toothpaste non-inferior to fluoride, and a 2022 systematic review called the nano-hydroxyapatite evidence comparable to fluoride but not yet conclusive. The one peer-reviewed hydroxyapatite gum trial we found measured dentin sensitivity, not cavities. Treat any of these gums as an addition to brushing.

Why is Minvelle, a competitor, writing this comparison?

Because people search for the pair and land on pages that sell one of the two. We sell a third gum, which is a conflict of interest, and we say so in the lede and in the fairness section. Every negative fact on this page is attributed to a specific page, audit or registry with the date we looked, we used no verdict words about either company, and both brands get a section on what they do well. If you want to check us the same way, the dose, ingredient list and batch certificate for Minvelle are on our transparency page.

Glossary

Hydroxyapatite: The calcium phosphate mineral that makes up most of tooth enamel. In oral-care products it is added as a synthetic powder with the aim of depositing mineral on enamel. Both brands on this page name it; neither says how much.

Nano-hydroxyapatite: Hydroxyapatite in particles small enough to meet the EU's nanomaterial definition of 1 to 100 nanometers in at least one dimension. A brand that says "nano" without a size in nanometers has made a label, not a measurement.

Dose per piece: The milligram amount of the mineral active in one piece of gum. It is the number that turns an ingredient into a quantity, and neither Underbrush nor Larineco publishes one.

Certificate of analysis (CoA): A batch-level lab document listing what was measured in a specific production run. It is the only public way to tie a stated dose to a product that shipped. Our database records zero downloadable documents for both brands.

Final sale: A refund-policy term meaning the item cannot be returned for a refund. Underbrush's refund policy applies it to chewing gum in all flavors.

Anchor pricing: Displaying a higher crossed-out price next to the price actually charged. When the crossed-out price is never charged, a per-piece figure computed from the "sale" price is not stable, which is why we did not compute one for Larineco.

Citation that resolves: A reference whose PubMed ID or DOI opens to a real record, and whose authors, journal, year and finding match what the brand said about it. One that opens to a different paper is recorded as "wrong record"; one that names the wrong authors is "wrong authors."

BBB rating: A letter grade from the Better Business Bureau, a US non-profit, based on complaint volume, response and other factors it defines. It is a record of complaints handled through BBB, not a product test, and a brand with no BBB profile has no grade either way.

Medical disclaimer: this article is educational and is no medical advice. It does not diagnose, treat or replace professional care. Talk to your dentist before changing your oral-care routine. If you have active tooth decay, a cracked tooth, or persistent sensitivity, see a dentist, because no gum can treat those.

Sources
  1. Paszynska E et al. Front Public Health 2023 (PMID 37533523): caries-preventing effect of a hydroxyapatite toothpaste in adults, 18-month randomized controlled trial, 189 participants; non-inferior to fluoride. Toothpaste, not gum.
  2. Wierichs RJ et al. Clin Oral Investig 2022 (PMID 35103837): systematic review and meta-analysis of nano-hydroxyapatite for caries prevention; comparable to fluoride, evidence "not yet conclusive."
  3. Porciani PF et al. J Clin Dent 2014 (PMID 25122980): the one peer-reviewed hydroxyapatite chewing gum trial our reviews found; outcome dentin hypersensitivity, not caries; neither brand's product.
  4. Najibfard K et al. J Clin Dent 2011 (PMID 22403978): remineralization of early caries by a nano-hydroxyapatite dentifrice. An Underbrush citation that resolved cleanly in our audit.
  5. Schlagenhauf U et al. J Investig Clin Dent 2019 (PMID 30701704): six-month randomized trial of a microcrystalline hydroxyapatite dentifrice on enamel caries. An Underbrush citation that resolved cleanly in our audit.
  6. Shi Q et al. J Clin Periodontol 2015 (PMID 25867215): effects of non-equilibrium plasma in ligature-induced peri-implantitis. The record that Underbrush's xylitol citation (attributed to Makinen) opens to; recorded as "wrong record" in our audit.
  7. Abdelrahman SM et al. Microorganisms 2024 (PMID 39203382): effects of mint oils on the human oral microbiome, pilot study. The real study behind Underbrush's mint-oil citation, which its page attributes to different authors.
  8. Minvelle, Underbrush gum review: what's verified, what's marketing (2026): ingredient list, price, storefront-versus-policy capture, Trustpilot figures as of 27 August 2026.
  9. Minvelle, Larineco gum review 2026: what checks out, and what doesn't: ingredient list, anchor pricing, refund policy dated 23 February 2026, BBB and ScamPulse figures, registry and address findings.
  10. Minvelle, The hydroxyapatite gum citation audit (2026): the resolve-and-match check applied to every brand's published references, run 27 August 2026; Underbrush 3 of 8 clean, Larineco cites no studies.
  11. Minvelle, Underbrush gum on Reddit: what the threads actually say (2026): 11 threads on texture, flavor, counterfeits and the absent dose question.
  12. Minvelle transparency page: 5.7 mg nano-hydroxyapatite per piece, 1.9 g piece, 18 pieces per box, particle form and size, safety data sheet and batch certificate as downloadable PDFs.
M

About the author

Max, Founder of Minvelle, builds an Austrian oral-care brand around one rule: publish the numbers, cite the sources, and say plainly what a product cannot do. He is not a dentist and does not play one online, which is why every article on this blog ends by pointing you to yours. The full formula behind Minvelle, every ingredient and dose, is public on the transparency page.

Two gums, one blank. Underbrush is the more documented company with the less careful footnotes. Larineco is the more disclosed list with the heavier complaint file. Both list hydroxyapatite and neither says how much. Whichever you choose, buy from the brand's own store, read the refund policy rather than the banner, chew after eating for the saliva, keep brushing with fluoride, and hold every brand in this category, ours first, to the standard of showing its work. Last reviewed: 4 September 2026.

A simple daily habit

One piece, once a day, with the dose on the page

Minvelle is a sugar-free gum with 5.7 mg of nano-hydroxyapatite per piece, made to be chewed one piece a day after meals or when brushing is not an option. A box holds 18 pieces, which is 18 days, and it sits alongside your fluoride routine rather than replacing it. The full formula and the batch certificate are published.

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