These parameters may also be readily estimated from long-term animal bioassay data. This may also be a disadvantage, though, because it may be difficult to incorporate pharmacokinetic knowledge into the estimation process. A schematic diagram of the model appears in Figure 7.3. Hormetic effects are obtained from this model whenever the net change in cell growth is negative. In contrast with detrimental effects, there is a limited range of doses over which beneficial effects are likely to be found.
Some scientists actually believe that hormetic effects are contrary to reason.
All these factors contribute to lessen the chances of detecting hormetic effects through synthesis of the scientific literature. The extra statistical power obtained from mathematical modeling is not available for hormetic studies when appropriate models are not available. The range of doses exhibiting hormetic effects will generally be too small and too ill-defined to accommodate a test for negative linear trend, since virtually every substance becomes toxic as the dose increases. Yet data such as the above strongly suggest a hormetic effect may exist.