The Impact of Receipts on Male Reproductive Health

For many of us, the small receipt handed to us after a coffee or fast-food purchase is an ordinary part of daily life. However, this simple contact may be part of a far more complex biological story than we realize. Thermal printer receipts contain chemicals that allow the print to appear when heated. One of these substances is Bisphenol A (BPA) . It is a compound frequently used in plastics, bottles, and metal coatings, but is also known for its endocrine-disrupting effects. In this article, we will examine two important studies from recent years to clarify whether BPA passes from receipts into the human body and what effect this exposure might have on the male hormonal system.

BPA Passage from Plug to Bloodstream

The PLOS ONE study, published in 2014, was one of the first comprehensive experiments to directly measure BPA transfer from thermal plugs to humans. Researchers designed a three-stage experiment to understand how much BPA passes into the body through the skin in different scenarios: dry hand contact , hand contact with disinfectant , and a combination of disinfectant, plug, and food .

Dry Hand Contact

In the first scenario, participants held a BPA-containing receipt with dry hands for 4 minutes without using any disinfectant or lotion . In this case, the amount of BPA transferred from the receipt surface to the hand was quite low — an average of only 6-7 micrograms .

The skin barrier provided effective protection; bioactive BPA (uBPA) levels measured in the blood remained undetectable in most participants . Although a very slight increase in conjugated BPA was observed in men after 30 minutes, this was not statistically significant . No significant increase was detected in urine levels after 60 minutes.

In short, healthy, dry skin was quite resistant to BPA penetration; in this scenario, the biological effect of contact with the plug was negligible. This amount was largely retained by the skin barrier; the amount of BPA that passed from the skin into the bloodstream was almost immeasurable.

In short, healthy, dry skin was quite protective against the penetration of BPA.

Contact after using hand sanitizer

In the second scenario, participants first applied an alcohol-based hand sanitizer (Purell), then held a plug of the same size. The aim at this stage was to measure the total amount of BPA that transferred from the plug's surface to the skin; that is, only the transfer was examined , not blood or urine .

The results were striking. Because the disinfectant dissolved the skin's protective oil layer and increased permeability, the BPA was much easier to remove from the plug's surface. In just 45 seconds , an average of 581 micrograms of BPA accumulated on hands — about 185 times more than on dry hands .

Interestingly, after 4 minutes this amount dropped to ~425 micrograms ; indicating that some of the BPA that reached the surface began to be absorbed through the skin during that time .

So, the BPA on the plug surface quickly transfers to wet skin, and some of it begins to be absorbed into the body at that moment . In this scenario, no measurements were taken in blood or urine, but the amount transferred was so high that systemic absorption is considered inevitable.

Hand Sanitizer + Receipt + Food (Realistic Scenario)

The third scenario was the combination that researchers described as the “most common in real life.” Participants applied hand sanitizer, as they would at any fast-food restaurant, held the receipt for 4 minutes , and then immediately ate 10 portions of french fries with the same hands . This chain of behavior (wet hands, receipt contact, then eating with hands) allowed BPA to enter the bloodstream through both the skin and oral mucosa .

In this case, bioactive BPA rapidly increased in blood samples . The average peak value ( Cmax ) reached 10.2 ng/mL in women and 5.6 ng/mL in men. This increase peaked at 15 minutes in women and at 60 minutes in men . A significant accumulation was also observed in urine at 90 minutes: approximately ~18 µg/g creatinine in men and around ~40 µg/g in women .

These data clearly show that contact with the plug is not “insignificant.” Just a few minutes of contact, especially if hand sanitizer was used, can lead to a rise in bioactive BPA in the blood within minutes . Moreover, this increase indicates that BPA enters the bloodstream directly through the skin and mouth , not via the gastrointestinal tract . This is because the measured BPA-glucuronide/free BPA ratio was low — meaning that “first-pass metabolism” was skipped.

You can think of it this way: BPA-glucuronide is the processed form of BPA that travels from the stomach and intestines to the liver . If the BPA-glucuronide ratio is low compared to BPA, it means that not all of the BPA went to the stomach, intestines, and liver , and some of it must have passed into the bloodstream through the mouth and skin without being converted into BPA-glucuronide .

What does BPA do in the body? Findings on Testosterone and the Reproductive System.

It's now clear that BPA enters the body, but what does it do? A 2023 animal study provided a direct answer to this question. Long-term exposure to BPA in male mice showed decreased testosterone production , impaired mitochondrial function , and weakened spermatogenesis. The hormone profile changed as follows: FSH increased , while LH and testosterone decreased . At a microscopic level, testicular cell death (apoptosis) increased, sperm quality decreased, and fertilization rates declined.

The mechanism is quite clear: BPA, thanks to its estrogen-like structure, activates ERα, ERβ , and G-protein coupled receptors. Through these receptors, signaling pathways such as PKA, MAPK, and PI3K are triggered. As a result, the activity of enzymes involved in testosterone synthesis decreases, energy production in mitochondria is disrupted, and intracellular oxidative stress increases. This picture confirms that chronic and high-dose BPA exposure leads to steroidogenesis disorders in Leydig cells .

HOW BIG IS THE REAL RISK?

When we read the two studies together, the picture that emerges should be evaluated in a balanced way: Yes, BPA from thermal plugs does indeed leach into the human body. Yes, animal studies show that BPA can lower testosterone and impair sperm function. But the dose in human exposure is much lower .

The average BPA level of 5–10 ng/mL reached in the receipt scenario , while several times higher than the general population average, is much lower than the levels that produce an effect in animal studies. Therefore, handling or occasional contact with a single receipt does not disrupt the endocrine system. However, if this behavior is repeated dozens of times a day , for example in individuals such as cashiers, waiters, or baristas, repeated “micro-exposures” may become significant over time. The hormonal effects of cumulative low-dose exposure in these individuals are not yet fully understood, but it is not biologically impossible .

Result: A Small Plug, A Silent Exposure

The most logical conclusion to draw from this data is that BPA absorption from thermal plugs is a real phenomenon, but it depends on the circumstances.

• Dry hand + plug → Low transfer, negligible systemic effect.

• Disinfectant + plug (wet hand) → Very high transfer (581 µg), high absorption potential.

• Disinfectant + receipt + eating with hands → Blood levels of 5–10 ng/mL bioactive BPA within minutes , systemic absorption proven.

  
  

So it's not just the receipt alone that determines the risk, but the chain of behavior .

The effects of BPA on the male reproductive system are clear at high doses, but more human studies are needed to understand the long-term consequences of low doses from plugs. Nevertheless, it is possible to reduce exposure with simple measures:

• Not getting a receipt immediately after using hand sanitizer,

• Washing hands after handling the receipt and before eating,

• Choosing digital receipts,

• Use BPA-free paper if there is occupational exposure.

  
  

These small precautions can significantly reduce the amount of chemical exposure one is unknowingly subjected to. Ultimately, thermal plugs are not a "danger alarm," but rather a matter of awareness requiring conscious thought.

References:

• Hormann AM, Vom Saal FS, Nagel SC, Stahlhut RW, Moyer CL, Ellersieck MR, Welshons WV, Toutain PL, Taylor JA. Holding thermal receipt paper and eating food after using hand sanitizer results in high serum bioactive and urine total levels of bisphenol A (BPA). PLoS One. 2014 Oct 22;9(10):e110509. doi: 10.1371/journal.pone.0110509. PMID: 25337790; PMCID: PMC4206219.

  
  

• Ryu DY, Pang WK, Adegoke EO, Rahman MS, Park YJ, Pang MG. Bisphenol-A disturbs hormonal levels and testicular mitochondrial activity, reducing male fertility. Hum Reprod Open. 2023 Nov 15;2023(4):hoad044. doi: 10.1093/hropen/hoad044. PMID: 38021376; PMCID: PMC10681812.