Likewise, in men, improved libido or sexual performance may be the result of activation of the ER receptors that mediate these functions centrally or activation of local receptors in the pelvic area directly as male hormones decline in a somewhat similar fashion. It is human nature to try to push the dose forever upward in attempts to find the maximum purported effect. Like all hormones there is a window of optimal effect. All hormones are pulsatile in nature. There are none that are steadily produced indefinitely.
Cellular effects vary with the changing bio-rhythms of cell cycles and cell functions.
Hormonal receptors also are variable in activity, turned on either through a gene switch or by activation of chemical messengers to turn on or off hormonal functions. Without these switches and variable hormonal controls there would be chaos inside cells once a powerful hormone enters to trigger a function. Overstimulation by hormones or hormonal compounds from herbs may result in down-regulation of the receptor through central genetic or secondary mechanisms. In other words, more is not always better. Many of the hormonally activating herbs that contain phyto-estrogens or androgenic compounds work by activating estrogen or androgen receptors in human cells.