You may be familiar with the bro-science meme telling you not to handle receipts because they contain toxic chemicals that can wreak havoc with your hormones. Well, guess what? The meme is true.

Let’s take a look at precisely why avoiding handling receipts and other forms of thermal paper isn’t such a crazy idea after all. So you care deeply about your health. You work out. You filter your tap water. You buy local organic produce. Looks like you’re gonna make it, right? But then, at the checkout, the cashier hands you the receipt.

Dive in slow-motion bullet time to get out of the path of the incoming receipt? Drop your shopping and run screaming from the store? Don a special glove to receive the receipt and then carefully deposit it in a lead-lined box you carry specifically for the purpose? Accept the receipt meekly and slowly dissolve into a puddle on the floor like something out of an ’80s body-horror movie?

So far, so silly. But the truth is, measurable levels of the powerful endocrine disruptor BPA are found in the thermal paper used in receipts (including from ATMs and card machines), airline boarding passes, movie tickets, prescriptions labels and food labels.

BPA is added to many kinds of thermal paper to allow them to produce visible text or colour when heat is applied. Endocrine disruptors are a ubiquitous threat to health in the modern world. So much so, in fact, that we’ve devoted an entire series of articles to them. We suggest you start with this one-stop primer on the subject.

As well as causing serious disruption to hormone levels by mimicking the effects of the female hormone estrogen, BPA has been linked to obesity. A recent study of zebrafish showed that background levels of BPA in the environment are enough to make the fish overeat and, as a result, become seriously overweight.

After genetic analysis, the researchers concluded that the chemicals were having these effects through activating the CB1 cannabinoid gene. Interestingly enough, the cannabinoid receptors are also stimulated by consumption of omega-6-rich vegetable oils, as we discussed in a recent article on why you should be eating butter. The cannabinoid receptors play an extremely important role in governing appetite, and their stimulation by compounds derived from omega-6 fats (endocannabanoids) is thought to be one of many reasons why our current modern diet, which has a surfeit of omega-6, is doing us such harm.

BPA has already been found harmful and banned from use in baby bottles and sippy cups. Although most research has focused on exposure via food and drink, there is clear evidence that BPA can pass into the body through the skin.

Studies from 2011, 2014 and 2017 have substantiated this.

According to Dr. John Warner of the Warner Babcock Institute for Green Chemistry, “There’s more BPA in a single thermal paper receipt than the total amount that would leach out from a polycarbonate water bottle used for many years.”

Warner has carried out a number of experiments to determine whether there are measurable amounts of BPA in thermal paper since the early 2000s.

“I’d send my students out to local stores to get their cash register receipts.” When they returned to the lab, they’d dissolve the paper and run it through a mass spectrometer, a machine to measure the chemical composition of materials.

His students found the telltale spike that indicated BPA in many of the receipts and, what’s more, receipt papers that used BPA looked identical to those that didn’t.

Although deniers will claim that BPA is safe at low levels, the point they’re missing is that exposure is cumulative. As we’ve already been at pains to show in our articles on the subject, the whole environment is loaded with toxic chemicals that can ruin your health — atrazinechlorpyrifosglyphosate — and their effects only get worse with repeated exposure.

So even if you don’t do your best Neo impression the next time the cashier hands you a receipt, you really would be better off avoiding touching thermal paper. Our recommendation would be either to refuse the receipt politely or to ask for it to be put in the bag for you if you need it. If you do have to handle a receipt or other form of thermal paper, wash your hands properly afterwards.

Also, mailing labels are also made from toxic thermal paper.