Does ZYN Contain Formaldehyde or Fiberglass? Myths vs Lab Tests

By PouchGuide Editorial Team · Published October 3, 2026

Two claims about ZYN circulate online: that it contains fiberglass, and that it contains formaldehyde. The short answer: there’s no evidence of fiberglass, but a lab study did find formaldehyde at low levels. Here’s what testing shows.

Does ZYN contain fiberglass?

There’s no evidence it does. ZYN’s UK site lists the pouch filling as cellulose, a plant-based fiber, along with nicotine, pH adjusters, sweetener, flavorings and, in regular pouches, water. We found no lab test or study reporting fiberglass in ZYN or other major pouch brands.

The myth probably comes from the tingling or burning feeling, which people sometimes describe as “tiny cuts” in the gums. That sensation is explained by nicotine and pH, not glass fibers (see why ZYN burns). The gum irritation and lesions some users get at the pouch site are well documented, and they’re linked to where and how often pouches are used (see white spots and gum recession).

Does ZYN contain formaldehyde?

Yes, at low levels. A 2023 study in BMC Chemistry tested ZYN (dry and moist) for harmful and potentially harmful constituents, and compared it with snus, moist snuff and nicotine replacement products.

Like ZYN, the nicotine gum and lozenges tested had no nitrosamines or PAHs.

Note that the study was funded by Swedish Match, ZYN’s maker, and all four authors worked for or were funded by the company. Most of the lab analyses were done at external laboratories. Independent research points in a similar direction, though. A 2026 national US study found that people who only used pouches had no rise in the tobacco alkaloids or metals tested, compared with non-users.

Is the formaldehyde dangerous?

Formaldehyde is a known carcinogen at high exposures. It’s also found at low levels in many everyday foods and products. The levels found in ZYN were low, and the FDA said in its January 2025 authorization that ZYN has substantially lower levels of harmful constituents than cigarettes and most smokeless tobacco. That doesn’t mean zero risk, and the FDA stressed its authorization “does not mean these tobacco products are safe.”

What about microplastics?

That’s a separate question, covered in ZYN and microplastics.

Bottom line

No fiberglass: ZYN’s pouch is plant-based cellulose, and no test has found glass fibers. Formaldehyde: yes, at low levels in a lab study, alongside no nitrosamines or PAHs. Pouches expose you to far fewer harmful chemicals than tobacco, but they still deliver an addictive dose of nicotine. See also nicotine pouch ingredients and do nicotine pouches cause cancer?.