Underbrush Gum Review: What's Actually Inside the Pack

Most chewing gum ingredient lists read the same way: a gum base, an artificial sweetener like aspartame or sucralose, and a handful of preservatives. Underbrush, made by Nathan & Sons, positions itself against exactly that formula. The real question is what's actually different, and whether it's worth the price difference.

What Underbrush Leaves Out

Nathan & Sons' site lists several ingredients it specifically avoids: polyvinyl acetate (a synthetic gum-base plastic), aspartame, sucralose, butadiene styrene, microplastics, artificial flavors, talcum powder, and preservatives. That's a meaningfully different starting point than most mainstream gum brands, which commonly use synthetic gum bases and artificial sweeteners as standard formulation choices.

Feature: No synthetic gum-base plastics or artificial sweeteners. What it means: The chewing texture and sweetness come from different, non-synthetic sources. Benefit: Relevant for anyone specifically trying to avoid those ingredient categories. Who it's for: Shoppers already avoiding aspartame, sucralose, or plastic-based gum bases for personal or dietary reasons

Why Ingredient Choice Matters More for Gum Than You'd Think

Gum is unusual among everyday products because it's chewed for extended periods, often 15 to 30 minutes or longer per piece, rather than consumed quickly like food. That extended contact time means whatever's in the base and sweetener spends more time interacting with your mouth than a typical snack would.

This is part of why some shoppers pay closer attention to gum ingredients specifically, even if they're not otherwise strict about ingredient lists elsewhere. It's less about any single ingredient being dangerous and more about wanting to know what's providing that flavor and chew for such an extended stretch.

Conventional gum bases have historically used food-grade synthetic polymers, which are commonly used and generally recognized as safe by regulatory standards, but which some shoppers specifically prefer to avoid for personal reasons similar to how some people avoid synthetic dyes or specific preservatives elsewhere in their diet, without there necessarily being a proven safety issue driving the preference.

What "Remineralizing" Actually Refers To

Underbrush is marketed as a "remineralizing" gum. Remineralization is a real dental concept it refers to saliva and certain compounds helping redeposit minerals into very early, non-cavitated enamel weak spots. Chewing sugar-free gum genuinely supports this process by increasing saliva flow, which helps neutralize acid and deliver minerals to tooth surfaces.

It's worth being precise here: this process applies to very early enamel changes, not to existing cavities or structural tooth damage. No gum, including this one, reverses a cavity or replaces brushing, flossing, and dental checkups. Treat "remineralizing" as describing a genuine, supportive mechanism, not a treatment claim.

Beyond the Gum: The Rest of the Lineup

Underbrush is the brand's flagship product, but Nathan & Sons also sells a Pearl Powder Tooth Scrub, a Pearl Serum with Rinse Cup, and an Uprising Energy Gum, along with bundles that combine several of these.

The Pearl Powder Tooth Scrub is positioned as a complementary product for people building out a broader "clean" oral-care routine rather than a gum-only approach. For someone only interested in the gum itself, these additional products aren't necessary; they're relevant mainly if you're specifically looking to replace multiple parts of your oral-care routine with similarly positioned products, rather than just swapping your everyday gum.

Flavors and Pack Options

The current lineup includes Mastic Mint, Berry, Cinna-Mastic, and Tropic Twist, plus a Variety Pack covering all four. Mastic Mint is the brand's most reviewed flavor, built around mastic a resin gum with its own history in traditional oral-care use.

Packs are available in 2-pack, 4-pack, and 8-pack sizes, with a subscription option offering a lower per-pack price than a one-time purchase. For anyone planning to use this daily rather than occasionally, the subscription math is worth comparing directly against one-time pricing before committing.

What Reviews Actually Say

The brand's site reports over 25,000 reviews and more than 1 million satisfied customers across its product line, with individual products showing high average ratings. These are the brand's own reported figures rather than independently audited statistics, so it's reasonable to treat them as a general signal of customer satisfaction rather than a guaranteed outcome for any individual buyer.

Customer feedback on the site commonly mentions a clean feeling after chewing, noticeable freshness, and a longer-lasting chew compared to standard gum, themes that show up across multiple individual reviews rather than being unique to one or two comments. As with any product's testimonials, individual experiences vary, and a single review isn't a guarantee of the same result for everyone.

Who This Actually Suits

Good fit if you:

• Already read gum ingredient labels and want to avoid synthetic sweeteners or plastic gum bases
• Chew gum daily and want an option positioned around saliva-supportive, sugar-free chewing
• Like the idea of trying mastic-based flavors specifically

May want to compare further if you:

• Are mainly looking for the cheapest daily gum option, since this sits at a premium price point compared to mainstream brands
• Want a specific medical or cavity-prevention outcome, which isn't something any gum can promise
• Haven't tried mastic flavor before and are unsure if you'll like the taste profile

Considering the Subscription

The subscription structure includes a lower per-pack price, along with the brand's stated recurring-order perks. If you're gum-chewing daily, this is the more cost-effective route long term. If you're just curious and want to try one flavor first, a one-time single-pack or the try-once option is the lower-commitment way to test it before subscribing.

Final Take

Underbrush's ingredient list is a genuine departure from mainstream gum formulas, and the remineralization angle reflects a real, if limited, mechanism rather than pure marketing invention. Whether it's worth the price comes down to how much you value avoiding synthetic sweeteners and gum-base plastics in a daily habit you already have.