That Receipt in Your Wallet May Disrupt Hormones — A Safer Alternative Could Be Emerging
If you have a receipt in your wallet right now, you’re carrying more than proof of purchase. Thermal paper — the heat-sensitive material used in receipts, tickets, and shipping labels — is coated with chemicals known to interfere with hormones. These papers are handled daily, stored in pockets and bags, and touched repeatedly, making them one of the most common sources of routine chemical exposure most people never think about.
Most thermal paper depends on bisphenol chemicals to produce text when heated — compounds that have been linked to hormone disruption. Now, researchers report a way around that tradeoff. In a study published in Science Advances, a team describes thermal paper coatings made from plant-based molecules derived from wood and sugars that perform like conventional paper, without relying on bisphenols.
“We have developed thermal paper formulations — which are commonly found in daily products like cash receipts, package labels, airline tickets, etc. — made from plant-based molecules that have very low or no toxic signatures,” said Jeremy Luterbacher, one of the study’s authors, in a press release.
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A New Way to Make Receipts Without BPA
Instead of starting from scratch, the researchers looked to a material plants already make in abundance. Lignin — the polymer that gives wood its stiffness — contains chemical features capable of driving the color-changing reaction at the heart of thermal printing. It’s also renewable, plentiful, and largely treated as waste, making it an appealing foundation for rethinking thermal paper chemistry.
The catch is that lignin isn’t naturally printer-friendly. Standard extraction methods leave it dark, chemically inconsistent, and difficult to control — all problems for a material meant to produce crisp, readable text. To overcome that, the team used a refined extraction approach that yields lighter, more uniform lignin molecules. By stripping away many of the light-absorbing components, they created a version of lignin that could mix evenly into thermal coatings without dulling the printed image.
Heat adds another layer of complexity. Thermal paper only works if its components react at the right temperature. To make lignin respond under commercial printing conditions, the researchers added a heat-activated “sensitizer” — a compound that melts during printing and facilitates interaction between the dye and developer. Rather than relying on petroleum-based additives, they tested a sensitizer derived from plant sugars, using a molecule related to xylan, a common component of plant cell walls. The resulting coating could then be applied to paper and tested using real printers.
Making Lignin Work for Printing
When heated, the plant-based coatings produced clear, readable text, reaching contrast levels needed for everyday thermal paper. The material also proved stable over time. Samples exposed to light resisted background darkening, and printed markings remained legible long after they were made.
Although the contrast does not yet exceed that of optimized commercial paper, the material met a practical standard: it printed as well as BPA-based products. That matters because even modest losses in image quality can make new materials unworkable at an industrial scale.
Safer Thermal Paper, Lower Hormone Effects
The biggest difference emerged in biological testing. The lignin-based developers triggered estrogen-like responses at levels hundreds to thousands of times lower than BPA, while the sugar-derived sensitizer showed no measurable estrogenic activity under the same conditions.
The results suggest that thermal paper does not have to rely on bisphenols to work. By combining plant-derived molecules with relatively simple processing steps, the researchers outline a path toward receipts and labels that perform as expected — without inadvertently increasing everyday chemical exposure. While further refinement and large-scale testing remain ahead, the study points to a safer alternative for one of the most common materials people handle without thinking twice.
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