What's Really in Your Chewing Gum? The Case for Going Plastic-Free

Most commercial chewing gum contains synthetic plastic polymers. A March 2025 UCLA study confirmed they shed into your saliva every time you chew. Here's the full picture — and what to do about it.

Originally published November 2025 · Updated April 2026 with the March 2025 UCLA American Chemical Society study on microplastic release from chewing gum, the May 2025 EWG analysis, and the September 2025 FoodNavigator industry reformulation report

Chewing gum feels like an entirely innocuous habit. It freshens breath, is widely recommended by dentists for saliva stimulation, and is consumed by hundreds of millions of people daily. Most people have never given a moment's thought to what the gum base is actually made from.

The answer — for the vast majority of commercial gum sold today — is plastic.

A pilot study presented at the American Chemical Society's spring 2025 meeting in San Diego by researchers from UCLA found that chewing gum — even gum labelled as natural — can release hundreds to thousands of microplastics into the body. The findings have been widely reported, but the full picture of what is in modern gum, what the research actually says, and what the practical alternatives are deserves a more careful treatment.

TL;DR

• The March 2025 UCLA study found that chewing gum releases approximately 100 microplastic particles per gram of gum. A standard piece weighs 1.5 to 6 grams, meaning one piece releases between 150 and 600 particles. A person chewing 160 to 180 pieces of gum annually could ingest approximately 30,000 microplastic particles from gum alone.
• The most abundant polymers found were polyolefins — a group that includes polyethylene (used in plastic bags) and polypropylene (used in plastic packaging). Both synthetic and natural gums contained the same polymer types.
• 94% of microplastic particles were released during the first eight minutes of chewing — suggesting that chewing one piece longer rather than replacing it frequently reduces overall exposure.
• The lead researcher's position is calibrated: "Our goal is not to alarm anybody. Scientists don't know if microplastics are unsafe to us or not. There are no human trials."
• Genuinely plastic-free gum — made from chicle or mastic resin — exists and is increasingly available. It performs comparably to synthetic gum for oral health purposes.
• The environmental impact of synthetic gum is significant and separate from the health question: gum litter persists in the environment for decades to centuries.

What Modern Chewing Gum Is Actually Made From

The original chewing gum was chicle — a natural latex harvested from the sapodilla tree, used by the Maya and Aztec civilisations for centuries before commercial gum was developed in the 19th century. Chicle biodegrades naturally and has no association with microplastic release.

By the mid-20th century, as global gum demand expanded beyond what natural chicle sources could supply, manufacturers switched to synthetic polymer bases. Today, the gum base in most commercial products — including major brands like Extra, Wrigley's, and Airwaves — is a proprietary blend of synthetic polymers.

The specific polymers identified in the UCLA study include polyolefins — polyethylene, used in plastic bags, and polypropylene, used in plastic packaging. Both synthetic and natural gum brands tested contained these same polymer types, which explains why there was no significant difference between the two categories in microplastic release.

Manufacturers are not required to specify the exact composition of their gum base on packaging — it is permitted to be listed simply as "gum base" on ingredient labels, with no further disclosure. This is why most consumers have no idea what they are actually chewing.

Other gum base components — softeners, resins, fillers, and antioxidants — also vary between products without mandatory disclosure. The lack of labelling transparency is a significant regulatory gap that the 2025 research has brought into sharper focus.

The UCLA Study: What It Found and What It Didn't

The March 2025 UCLA study is the first systematic investigation of microplastic release from chewing gum during normal use. Understanding its methodology and limitations is important for interpreting the findings accurately.

Researchers at UCLA tested five commercially available synthetic gum products and five natural gum alternatives. Both types released comparable levels of microplastics when chewed — approximately 100 particles per gram on average. For a 6-gram piece of gum, that translates to approximately 600 particles per piece, or over 3,000 for a very large piece.

A particularly useful practical finding: 94% of the particles were released during the first eight minutes of chewing. This means that someone chewing a single piece of gum for 20 minutes releases only slightly more microplastics than someone chewing for eight — and chewing one piece longer rather than going through multiple pieces significantly reduces total particle exposure.

The study was a pilot — it tested only 10 brands, was presented at a conference rather than published in a peer-reviewed journal, and did not measure nanoplastics (particles smaller than one micrometre), which the lead researcher noted may be present in additional quantities beyond what the instruments could detect. It also did not establish health effects — it established exposure.

"Our goal is not to alarm anybody," said Sanjay Mohanty, the study's principal investigator and an engineering professor at UCLA. "Scientists don't know if microplastics are unsafe to us or not. There are no human trials. But we know we are exposed to plastics in everyday life, and that's what we wanted to examine here. Animal studies and studies with human cells show that microplastics could cause harm, so while we wait for more definitive answers, individuals can take steps to reduce their exposure."

This is the appropriate framing. The concern is real. The evidence for specific harm at these exposure levels is not yet established. The precautionary case for reducing exposure where practical is reasonable.

The Natural Gum Surprise

The most counterintuitive finding of the UCLA study is that natural gums — those marketed with natural or plant-based positioning — released comparable microplastics to synthetic gums.

The UCLA researchers found no major difference between standard and eco-positioned gums. Chewing one gram of synthetic gum released an average of 104 microplastic particles, while one gram of natural gum released 96. The researchers noted they were not certain whether this was because of the ingredients used or some other factor, and acknowledged that other types of food can be contaminated with microplastics due to how they are processed or packaged.

The explanation most likely relates to manufacturing contamination rather than the gum base itself — natural gum bases processed in facilities that also handle synthetic materials may be contaminated with plastic particles during production. This is a different mechanism from synthetic gum bases, where the microplastics are shed from the gum base material itself during chewing.

The practical implication: "natural" labelling on gum is not a reliable indicator of lower microplastic content. Genuinely plastic-free gum — using chicle or mastic as the base, with verified clean manufacturing — is a different proposition from gum that is merely marketed as natural.

The Oral Health Question

Before addressing what to switch to, it is worth acknowledging what chewing gum actually does for oral health — because the benefits are real and worth preserving.

Chewing stimulates saliva production. Saliva is the mouth's primary defence system — it neutralises acids produced by bacteria after eating, remineralises tooth enamel, clears food particles and bacteria, and reduces the dry oral conditions that allow pathogenic bacteria to proliferate. Chewing sugar-free gum for 20 minutes after meals has well-established evidence for caries prevention.

The specific sweetener in sugar-free gum matters significantly:

Xylitol is the most evidence-backed sweetener for oral health. It is not fermented by the oral bacteria that produce acid and contributes to plaque, and active xylitol consumption has been shown to reduce Streptococcus mutans — a primary cause of tooth decay — in multiple controlled trials. The protective dose is approximately 5 to 10 grams per day from all sources combined.

Sorbitol is widely used and has some protective effect compared to sugar, though less than xylitol. It produces mild gastrointestinal effects at high doses.

Aspartame and acesulfame-K — common in many sugar-free gums — have no direct oral health benefit. They do not feed bacteria, which is the minimum requirement for caries-protective gum, but they do not provide the active benefit of xylitol. As discussed in our separate article on sweeteners and cognitive decline, aspartame and acesulfame-K have been associated with faster cognitive decline in a 2025 Neurology study.

Stevia — used in some natural gums — is inert in the mouth and does not appear to carry the same concerns as synthetic sweeteners.

The Environmental Impact

The health question is separate from the environmental question — and both are significant.

Chewing gum residues are highly persistent in the environment and can persist for 5 to 500 years, with some estimates suggesting up to 1,000 years depending on environmental conditions. A single piece of plastic gum can release in excess of 250,000 microplastic particles into the environment after disposal. Chewing gum is described as a significant but overlooked source of both microplastic ingestion and environmental pollution.

More than 100,000 tonnes of gum waste are dropped globally each year. In UK cities, gum litter is one of the most costly and persistent forms of street waste to remove — estimates suggest it costs local councils millions annually in cleaning costs. Synthetic gum adheres to paving and does not biodegrade.

Natural gum bases including chicle and mastic break down naturally over months. This is a meaningful environmental difference regardless of the health consideration.

What Genuinely Plastic-Free Gum Looks Like

Genuinely plastic-free gum uses one of three natural bases:

Chicle — the original natural gum base from the sapodilla tree, native to Central America. It has a slightly softer, more natural chew than synthetic gum and biodegrades naturally. Chicle is the basis for most verified plastic-free gum brands.

Mastic resin — the hardened sap of the mastic tree (Pistacia lentiscus), grown primarily on the Greek island of Chios. Mastic gum has an additional benefit beyond the plastic-free base: it has clinical evidence for reducing H. pylori — the bacterial species associated with stomach ulcers and gastric cancer — in small trials. It has been chewed medicinally in the Mediterranean for centuries.

Natural rubber and plant-based resins — various other plant-derived bases used by smaller manufacturers.

The key distinction is not simply "natural" on the label but specific gum base disclosure — chicle, mastic, or named plant resin — combined with evidence of clean manufacturing.

The global plastic-free chewing gum market is valued at approximately $132 million and growing, driven by the combined pressure of consumer awareness, regulatory scrutiny, and the evidence accumulating around microplastic exposure.

Reading Gum Labels

The challenge with choosing lower-microplastic gum is that gum base composition is not required to be disclosed on UK packaging. "Gum base" as a listed ingredient tells you nothing about whether it is synthetic or natural.

What to look for:

• Specific base ingredients — "chicle," "mastic resin," or "natural tree resin" named explicitly in the ingredient list. If only "gum base" is listed with no further detail, assume it is synthetic unless the brand explicitly states otherwise with evidence.
• Sweetener transparency — xylitol named as a sweetener indicates oral health benefit. Aspartame or acesulfame-K present indicates synthetic sweetener use.
• Certifications — B Corp, certified compostable, or specific plastic-free certifications provide third-party verification beyond marketing language.
• Packaging — plastic-free gum brands typically use paper or cardboard packaging rather than plastic blister packs or foil-lined wrappers. The packaging commitment is often a reliable indicator of base material commitment.

Practical Switches

• True Gum (truegum.com) — Danish-made, chicle-based, sugar-free with xylitol, comes in paper packaging. Widely available in UK health food shops and online.
• Chewsy (chewsy.co) — UK-based brand using chicle base with xylitol. Available in supermarkets including Waitrose and independent health shops.
• Peppersmith (peppersmith.co.uk) — UK brand using a natural gum base with xylitol, in recyclable packaging. Available in major supermarkets.
• Mastic gum — available from Greek or Mediterranean food shops and online retailers. Less sweet, more resinous flavour than conventional gum. Most useful for people interested in the specific H. pylori and digestive benefits.

Frequently Asked Questions

Does all chewing gum contain plastic? Most commercial chewing gum contains synthetic polymer gum bases including polyethylene and polypropylene — materials derived from petrochemicals. The March 2025 UCLA study confirmed these polymers shed as microplastics during chewing. Genuinely plastic-free alternatives use natural bases including chicle or mastic resin. These are increasingly available but represent a small fraction of total gum sales.

Are natural gums plastic-free? Not necessarily. The UCLA study found that gums marketed as natural released comparable microplastics to synthetic gums. This is likely due to manufacturing contamination rather than the gum base itself in some cases, but it means "natural" labelling is not a reliable indicator. Genuinely plastic-free gum requires specific disclosure of the gum base material — chicle, mastic, or named plant resin.

Is chewing gum bad for you? Sugar-free gum has well-established oral health benefits — stimulating saliva production, neutralising acids, and reducing caries risk, particularly when containing xylitol. The microplastic finding adds a new risk dimension but does not negate these benefits. The precautionary approach is to switch to verified plastic-free alternatives rather than stop chewing gum entirely, preserving the oral health benefits without the microplastic exposure.

What is the healthiest gum to chew? Based on current evidence, a verified chicle-based or mastic-based gum sweetened with xylitol represents the best available option — providing the oral health benefits of sugar-free gum without synthetic polymer microplastic shedding and without sweeteners associated with cognitive decline concerns. UK brands including True Gum, Chewsy, and Peppersmith fit this profile.

How many microplastics does chewing gum release? The March 2025 UCLA study found approximately 100 microplastic particles per gram of gum. A standard piece weighs 1.5 to 6 grams, translating to 150 to 600 particles per piece. 94% of particles are released in the first eight minutes of chewing. Someone chewing 160 to 180 pieces annually could ingest approximately 30,000 microplastic particles from gum alone — though whether this quantity causes health harm has not been established in human trials.

Does chewing gum longer reduce microplastic exposure? Yes — since 94% of microplastics are released in the first eight minutes, chewing one piece for longer rather than replacing it frequently reduces total particle release. Choosing a 3-gram piece and chewing it for 20 minutes exposes you to fewer total particles than chewing two 1.5-gram pieces for 10 minutes each.

The Bottom Line

Modern chewing gum is, in the technical sense, a plastic product — and the March 2025 UCLA research has confirmed that the synthetic polymers in its base shed as microplastics into saliva during normal use. The health significance of this specific exposure is not yet established in human trials, but the precautionary case for reducing it is the same as for other microplastic exposures.

The good news is that switching to verified plastic-free alternatives does not require giving up the oral health benefits of gum — it requires reading labels carefully and choosing brands that disclose their gum base explicitly. Chicle-based gum with xylitol provides the same saliva stimulation, acid neutralisation, and breath-freshening function without synthetic polymer exposure.

This is one of the simplest swaps in a broader approach to reducing microplastic exposure. For a structured guide to reducing microplastics across food, water, and home environments, the Microplastics Reset from the Reset Series™ covers the highest-impact changes available.

Related reading: Microplastics in the Human Body: What the Research Actually Shows · The Oral Microbiome: Why Fresh Breath Is More Important Than You Think · Sweeteners, Diet Soda and Cognitive Decline: Evidence or Hype?

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