BACKGROUND Hormesis is a binary response phenomenon with low-dose stimulation (or inhibition) of effects by substances producing opposite high-dose responses. Hormesis, after decades of obscurity, has undergone a renaissance in recent years, with rapid growth benefiting greatly from the systematized efforts of such proponents as the hormesis group at the University of Massachusetts-Amherst led ...

The hormesis concept has broad implications for biology and the biomedical sciences. This perspective on hormesis concentrates on toxicology and toxicological risk assessment and secondarily explores observations from other fields. It considers the varied manifestations of hormesis in the context of a broad family of biological stress responses. Evidence for hormesis is reviewed, and the hormes...

Policy implementation of hormesis has to date focused on regulatory applications. Toxic-tort litigation may provide an alternative policy venue for real-world applications of hormesis. Businesses and government entities, who are sued by individuals claiming to have been injured by exposure to very low levels of toxic substances may defend those cases by deploying hormesis to argue that such exp...

OBJECTIVE This analysis is a critical assessment of current hormesis literature. I discuss definitions, characterization, generalizability, mechanisms, absence of empirical data specific for hormesis hypothesis testing, and arguments that hormesis be the "default assumption" in risk assessment. DATA SOURCES Hormesis, a biological phenomenon typically described as low-dose stimulation from sub...

Hormesis, a dose-response phenomenon characterized by a low-dose stimulation and a high-dose inhibition, has been the object of controversy due to its challenging of basic understandings of the dose-response relationship and implications for risk assessment. The author addresses issues relating to the definition of hormesis, the relationship of hormesis to risk assessment and risk management, a...

The manipulation of oxygen to trigger the stimulatory response known as hormesis is an area interest in insects that was born almost fifty years ago. Varying low-oxygen treatments have been investigated many times since with differing responses found; some hormetic/some harmful. In this review, we summarize recent advancements a focus on severe hypoxia and anoxia. These two fall below critical ...

Documented biphasic dose-responses date some 150 years back; however, massive evaluations of the occurrence pollutant-induced hormesis, its quantitative characteristics, and underlying mechanisms have been performed only in recent years. One reasons why hormesis is not included ecological risk assessment may be poorly explored relevance to levels biological organization beyond individual. Here,...

Organisms survive best, or show high fitness, in the habitats in which they most commonly occur, a phenomenon referred to as hormesis in the literature of toxicology. Examples of hormesis accumulate rapidly in the literature. However, a lack of underlying models has led many to doubt its existence, especially for ionizing radiation. The evolutionary model developed here indicates that all poten...

Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET) value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio) as the in vivo vertebrate model. The toxicity of these ionizin...

Much confusion surrounds the concept of hormesis and what its biological meaning represents. This paper provides a definition of hormesis that addresses its historical foundations, quantitative features, and underlying evolutionary and toxicologically based mechanistic strategies. Hormesis should be considered an adaptive response characterized by biphasic dose responses of generally similar qu...