The idea that a simple paper receipt could affect the body’s hormone balance, specifically testosterone, has become a common concern. This concern stems from the chemicals used in the heat-sensitive paper from which most modern receipts are printed. Scientific evidence suggests that while exposure does occur, the resulting biological mechanism relates to the body’s endocrine system. This article explores the specific compounds involved, the biological mechanism of interference, and the current scientific understanding of how handling receipts might impact testosterone levels.
The Chemicals in Thermal Paper
The chemicals at the center of this discussion are Bisphenol A (BPA) and its common replacement, Bisphenol S (BPS). These substances are not part of the paper fibers themselves but are applied as a coating within the thermal layer of the receipt paper. The function of BPA and BPS is to act as color developers, reacting with a colorless dye when exposed to the heat of the printer head to create the dark text or image.
Because these chemicals are not chemically bound to the paper matrix, their unbound, powdery nature allows them to easily transfer from the receipt surface to anything that touches them, including human skin or wallets. The concentration of these bisphenols in thermal paper is often high, sometimes making up as much as 2% of the paper’s total weight. Due to health concerns, many manufacturers have replaced BPA with BPS, but BPS is structurally similar and may present comparable issues.
Endocrine Disruption: The Biological Mechanism
The potential for bisphenols to impact testosterone levels is rooted in their classification as endocrine-disrupting chemicals (EDCs). Endocrine disruption describes a process where an external chemical interferes with the body’s natural hormone signaling system. These chemicals, including BPA and BPS, can mimic or block the action of natural hormones like estrogen and testosterone.
Specifically regarding male hormones, bisphenols can interfere with the hypothalamic-pituitary-gonadal (HPG) axis, which regulates testosterone production. The compounds may bind to hormone receptors, such as the androgen receptor, preventing natural testosterone from docking and carrying out its function. Bisphenols can also disrupt the activity of enzymes, such as CYP17A1 and HSD3B, which are necessary for the final stages of testosterone synthesis in the testes. This interference can potentially lead to a reduced overall production of the hormone.
Dermal Absorption and Measured Testosterone Levels
The primary route of exposure from receipts is dermal absorption, meaning the chemicals pass through the skin into the bloodstream. Research has confirmed that merely holding a thermal receipt for a short period causes a measurable transfer of bisphenols to the skin. Once on the skin, the compounds are absorbed and can be detected in the blood serum and urine shortly after handling.
The amount of chemical absorbed increases if the skin is moist, greasy, or has recently been treated with products. For example, using hand sanitizer or lotion before touching a receipt can increase the absorption of bisphenols by up to a hundredfold. This absorption route is significant because, unlike ingested bisphenols that are quickly metabolized by the liver, those absorbed through the skin enter the bloodstream directly, potentially leading to a higher concentration of the active chemical in the body.
Establishing a direct, clinically significant link between intermittent consumer receipt handling and a reduction in testosterone levels in healthy adults remains challenging. Studies show that occupational exposure, such as cashiers handling receipts for hours daily, results in significantly higher exposure levels, sometimes 50 times greater than the general public. While these workers show elevated levels of bisphenols, the long-term impact on systemic hormone levels is still under investigation. For the average person, the current consensus is that the exposure from brief contact, while detectable, is unlikely to cause a significant change in testosterone levels.
Minimizing Daily Exposure
Individuals concerned about exposure can take several steps to reduce contact with these chemicals. The easiest method is to opt for paperless or digital receipts whenever possible, eliminating the source of exposure. If a physical receipt is necessary, minimizing the handling time and avoiding creasing or crumpling the paper will reduce transfer.
Individuals can minimize exposure by following these measures:
- Wash hands thoroughly with soap and water immediately after handling thermal paper, especially before eating.
- Avoid touching receipts after applying hand sanitizer, lotion, or any product that may enhance skin absorption.
- Do not store receipts loosely in a wallet or purse alongside currency.
- Do not store receipts near food items, as the bisphenols can easily rub off onto other surfaces.