What is gum made of? From tree sap to the pack in your bag

Gum is made of four things: a base you chew, a sweetener, flavor, and a few helpers that keep pieces from sticking to each other. The sweetener and flavor dissolve while you chew. The base is the part that's still in your mouth twenty minutes later, and it has the most interesting story.

Pull a pack out of your bag and look. On a lot of labels the base gets two words: "gum base." Let's unpack those two words.

What "gum base" is allowed to mean

In the US, the FDA keeps a list of what can go into chewing gum base. It's a federal regulation called 21 CFR 172.615,¹ and it reads like two different shopping lists stapled together.

The first list is natural "masticatory substances," which is the regulation's word for stuff you chew. It includes chicle, a tree sap from Central America, plus a handful of other tree latexes with names like jelutong, sorva and massaranduba balata.

The second list is synthetic. It includes:

• butyl rubber (isobutylene-isoprene copolymer)
• butadiene-styrene rubber
• polyethylene
• polyisobutylene
• polyvinyl acetate
• paraffin and petroleum wax

If a few of those sound familiar, it's because you've met their cousins elsewhere. Polyethylene is the most widely used plastic in the world, the stuff of grocery bags and squeeze bottles.² Polyvinyl acetate is the polymer in white school glue.³ The versions in gum are food-grade and FDA-permitted. Several of them are also, chemically speaking, plastics and synthetic rubbers.

So when someone asks "is gum made of plastic," the honest answer is: it depends on the gum, and the label often won't tell you. "Gum base" can legally mean either list.

Why the label doesn't say

Labels commonly group everything in the base under that one name. It means you can read a whole ingredient list front to back and still have no idea whether your base came from a tree or a polymer plant.

That's why "plastic free gum" has become such a popular search. People want to know what they're chewing, which is a great instinct.

What's in ours

Our gum base is a proprietary blend of chicle, mastic, spruce, myrrh, and arabic. Chicle comes from the sapodilla tree and is the original chewing gum of the Americas. Spruce gum is resin from spruce trees, and it was sold as chewing gum in New England before chicle arrived. (We wrote a whole piece on how chicle became gum if you want the story.)

Here is the complete YAWANA SMILE ingredient list, in the order printed on the pouch:

Xylitol, Chicle Base, Gum Arabic, Hydroxyapatite, Rice Flour, Flavor, Spruce Gum, Coconut Oil, Calcium Bentonite Clay, Myrrh Gum, Spirulina, Carnauba Wax.

Twelve ingredients as printed on the pouch. Our gum-base blend is described above; the list preserves the printed ingredient names. The pouch carries a PLASTIC FREE mark, and what that mark describes is the gum base: no synthetic polymers from the second list. (The pouch itself is a different conversation, and we don't make claims about it.)

What the science says about microplastics in gum

In March 2025, researchers at UCLA presented a small pilot study on gum and microplastics. One person chewed pieces from ten gum brands, five with synthetic bases and five with natural ones, and the team counted the microplastic particles that ended up in saliva. Both kinds released particles, and in similar amounts: on average about 100 particles per gram of gum, and up to about 600 per gram for some pieces.⁴ It was a small conference study, not yet a peer-reviewed paper, and it only counted particles larger than 20 micrometers. Still, it means "plastic-free gum base" and "zero microplastics" are two different statements.

So here's what our PLASTIC FREE mark means: none of the synthetic polymers on the FDA's list are ingredients in our gum base. It describes what goes into the gum rather than a particle test. We haven't tested ours for microplastics yet, and if we do, we'll share the results.

How to check any gum in about ten seconds

1. Flip the pack. Front labels are marketing; the back is the ingredient statement.
2. Find the base. If it says only "gum base," you don't know which list it came from. If it names chicle or another tree sap, you do.
3. Look for a plastic-free mark, then check that the ingredient list backs it up.
4. Read the sweetener line while you're there. That's the next most common question we get, and we cover it in our xylitol guide.

Questions people ask

Is gum made of rubber? Some gum bases include synthetic rubbers like butyl rubber or butadiene-styrene rubber, which are on the FDA's permitted list. Natural chicle is a latex, so in the loosest sense it's rubbery too. The difference is where it comes from: a polymer process or a tree.

Is plastic-free gum less chewy? Tree-sap bases chew differently from synthetic ones. We'd rather you try ours than take our word for it.

Does plastic-free gum break down faster? We haven't tested how our gum breaks down in the environment, so we don't make any claim about it. Please throw it in the trash either way.

See it on a real label

We think the ingredient you chew for twenty minutes deserves more than two words on the back of a pack. That's why SMILE uses a proprietary blend of chicle, mastic, spruce, myrrh, and arabic and prints its ingredient list on the pouch. One flavor, extra fresh peppermint, 60 pieces to a resealable pouch.

If you've been hunting for a gum where you know what the base is, have a look. Questions about anything on our label? Email hello@yawana.shop.

Keep reading: Every ingredient in our gum, explained · Chicle: the tree sap that started chewing gum

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