Non-monotonic dose response
Some endocrine-active substances do not follow a simple “higher dose = higher effect” pattern.
Researchers have observed U-shaped or inverted-U responses in some models.
This means that very low doses can sometimes trigger biological responses that are not seen at higher levels.
The endocrine system’s sensitivity
The endocrine system is designed to respond to extremely low levels of natural hormones.
Because of this inherent sensitivity, even trace amounts of certain additives can potentially interfere with hormonal signaling.
When multiple such substances are present in a mixture, their combined low-dose effects may become more significant.
Why it matters for mixtures
If low doses can be active, combined low-dose exposures may be more relevant than expected.
This is one reason mixture research remains an active area of study.
Traditional safety testing often misses these effects by focusing only on high-dose toxicity to determine safe levels.
Frequently Asked Questions
Endocrine disruptors are chemicals that can interfere with the body’s endocrine (hormone) system and produce adverse developmental, reproductive, neurological, and immune effects.
Related pages
Sources
- Hormones and Endocrine-Disrupting Chemicals: Low-Dose Effects and Nonmonotonic Dose Responses — Vandenberg LN, et al. Endocrine Reviews (2012).
Summaries are educational and may be updated as regulations change.