Di-(2-ethylhexyl) phthalate is in the medical tubing connected to hospital patients. It is in the flexible plastic that makes IV bags squeezable and safe. It is in children's toys, shower curtains, raincoats, vinyl flooring, food packaging, and thousands of other everyday plastic products. It is, by volume, one of the most widely used plasticizer chemicals in the world — and new research presented at the Endocrine Society's ENDO 2026 annual meeting suggests that exposure during the earliest stages of human development may produce behavioral changes that last an entire lifetime.
According to ScienceDaily's June 17, 2026 coverage, MedicalXpress, and the Endocrine Society's ENDO 2026 press release, male rats exposed to DEHP during the prenatal and immediate postnatal developmental period exhibited elevated anxiety behavior as adults — even after all DEHP exposure had completely ended. The behavioral effects persisted into adulthood without continued chemical exposure.
"This research demonstrates that one of the most widely used plasticizers worldwide is capable of causing behavioral changes when the subject is exposed during the prenatal and immediate postnatal developmental stages, with this effect lasting over time," said lead researcher Osvaldo Juan Ponzo, M.D., Ph.D., professor of physiology at the University of Buenos Aires School of Medicine.
What the Research Found — and What the Reversal Finding Reveals
The study used the Elevated Plus Maze (EPM) test — a validated behavioral measure for anxiety in rodents — to track behavioral differences between DEHP-exposed and control male rats at multiple points through sexual maturation and into adulthood. DEHP-exposed male rats showed significantly higher anxiety-like behavior: they spent less time in the open arms of the maze (less time in exposed, potentially vulnerable positions) and more time in the closed, sheltered arms, a behavioral pattern consistent with heightened stress reactivity and anxiety.
Crucially, the behavioral changes were present in adult animals despite all DEHP exposure having ended well before testing. The chemical was not present. The anxiety was.
The finding implicates a specific biological mechanism. DEHP is a well-characterized anti-androgenic compound — it disrupts testosterone signaling, reducing the androgenic influence on brain development during critical windows. This matters for anxiety because testosterone and androgenic activity play a known role in regulating emotional reactivity and stress response. When DEHP reduces androgenic signaling during the prenatal brain development period, the developing neural architecture is shaped by reduced testosterone influence, and the resulting changes in how the brain processes threat and anxiety appear to persist into adulthood.
Ponzo also reported that the behavioral changes could be reversed: "These neuroendocrine changes can be reversed by treating with GABA agonists or testosterone." This is a significant finding. It suggests the neurobiological disruption is not permanent at the cellular level — the circuits can be recalibrated — but that the recalibration requires pharmacological intervention. Left untreated, the behavioral signature of early DEHP exposure persists.
| DEHP and Anxiety ENDO 2026 Study Key Data | Detail |
| Presented at | ENDO 2026, Endocrine Society Annual Meeting, Chicago, June 14, 2026 |
| Coverage dates | ScienceDaily, MedicalXpress, Newswise — June 16–17, 2026 |
| Lead researcher | Osvaldo Juan Ponzo, M.D., Ph.D., Professor of Physiology, University of Buenos Aires School of Medicine |
| Chemical studied | DEHP (di-(2-ethylhexyl) phthalate) — a phthalate plasticizer |
| Animal model | Male Wistar rats |
| Exposure window | Prenatal and immediate postnatal developmental stages |
| Behavioral test used | Elevated Plus Maze (EPM) |
| Outcome | Elevated adult anxiety behavior; persists after all DEHP exposure has ended |
| Mechanism implicated | Anti-androgenic disruption of testosterone signaling during neural development |
| Reversal | GABA agonists or testosterone treatment reversed behavioral changes |
| Products commonly containing DEHP | Medical tubing, IV bags, ventilators, children's toys, shower curtains, vinyl flooring, food packaging |
| Sex-specific finding | Significant in males; sex differences previously documented by Ponzo's prior PubMed studies |
Why Males Are Specifically at Risk — and What Prior Research Shows
The sex-specific nature of this finding is not accidental. DEHP's primary mechanism of endocrine disruption — anti-androgenic activity, suppressing testosterone signaling — has its most pronounced effects on organisms whose developmental programming is most testosterone-dependent during critical windows. Male mammalian brain development is more sensitive to androgenic disruption than female because the masculinization of specific brain circuits depends on testosterone exposure during precise gestational and neonatal windows.
Ponzo's laboratory has a decade of published work on this topic. A 2013 study by Carbone, Ponzo, and colleagues (PubMed) found that perinatal DEHP exposure specifically increased anxiety-like behavior in male rats at 45 and 60 days of age, while female rats did not show the same behavioral changes. That study established the sex-specific vulnerability; the ENDO 2026 data extends the finding to adult animals, confirming the behavioral changes are not a transient developmental artifact but a lasting modification of the anxiety response system.
The mechanism appears to involve disruption of how the hippocampus processes stress-related glutamatergic signaling. A 2025 IBRO Neuroscience Reports study from researchers in Tbilisi (PMC) confirmed that prenatal DEHP exposure altered the association of glutamatergic proteins with PTEN in the hippocampus of male rat offspring — a finding consistent with disrupted synaptic processing of stress signals as the molecular basis for the anxiety behavior.
What DEHP's Regulatory Status Is — and What That Means for People
DEHP is not an unregulated chemical. In the United States, the Consumer Product Safety Improvement Act (2008) restricts DEHP to 0.1% of the weight of children's toys and child care articles. The EPA classifies DEHP as a probable human carcinogen. The EU has classified it as a substance of very high concern (SVHC) and, in 2023, set deadlines restricting DEHP in medical devices — a category where the U.S. has not followed with equivalent restrictions.
The primary routes of exposure are ingestion (leaching from food packaging and containers), inhalation of dust in environments with DEHP-containing materials, and — most critically for the developmental window identified in this study — transplacental transfer during pregnancy and breastmilk transfer in the early postnatal period.
A major 2025 study published in eBioMedicine estimated that DEHP exposure may have contributed to over 356,000 cardiovascular deaths globally in 2018 — most heavily in Asia and the Middle East — through inflammatory mechanisms. The ENDO 2026 anxiety finding adds a neurobehavioral dimension to the compound's established health impact.
For pregnant individuals concerned about minimizing DEHP exposure, practical steps include avoiding PVC-containing soft plastic food packaging, using glass or stainless steel containers instead of flexible plastic, reducing consumption of processed foods in PVC packaging, and discussing DEHP exposure risk with their healthcare provider, particularly when considering plastic-heavy NICU care if a preterm birth is anticipated.
Frequently Asked Questions
What is DEHP and where is it found?
DEHP (di-(2-ethylhexyl) phthalate) is one of the world's most widely used plasticizers — chemicals added to polyvinyl chloride (PVC) plastic to make it flexible. It is found in medical tubing, IV bags, ventilators, children's toys, shower curtains, vinyl flooring, and food packaging.
What did the ENDO 2026 DEHP study find?
Presented at ENDO 2026 in Chicago and covered June 16–17, 2026: male rats exposed to DEHP during prenatal and immediate postnatal development showed elevated adult anxiety behavior, even after all DEHP exposure had ended. The behavioral changes could be reversed by treatment with GABA agonists or testosterone.
Why are males more affected than females?
DEHP disrupts testosterone signaling (it is anti-androgenic). Male brain development is more sensitive to this disruption because masculinization of specific neural circuits depends on testosterone exposure during critical developmental windows. Female rats in prior studies did not show the same behavioral changes.
Does this finding apply to humans?
The study was conducted in rats. Human translation is not guaranteed. However, the developmental window studied — prenatal and immediate postnatal — corresponds to human gestational development, a period when DEHP is known to cross the placenta. Epidemiological studies have linked maternal phthalate levels during pregnancy to behavioral changes in children.
What can pregnant people do to reduce DEHP exposure?
Avoid flexible PVC plastic food packaging and containers. Use glass, stainless steel, or rigid plastic (PP or HDPE) alternatives. Reduce processed food intake in plastic packaging. Discuss NICU equipment DEHP exposure concerns with your obstetrician or neonatologist if preterm birth is anticipated.
