Body and drug basics
Peak and trough
Last updated
After any exposure, the amount of a substance in the blood climbs to a highest point and then falls away to a lowest point before the next one. The high is the peak and the low is the trough. A single average figure hides both, which matters because the body can respond quite differently to a sharp spike than to the same total amount arriving gradually.
Why it matters here
The gap between peak and trough is what makes steady exposure and pulsed exposure biologically different, and it connects directly to whether receptors stay responsive. Many of the body's own hormones are released in pulses precisely because the trough is doing work of its own.
What it is not
The peak is not when an effect is strongest. Blood level and response often lag one another, sometimes by hours, so the highest concentration and the largest change are not the same moment. Peak also describes a concentration reached, not the amount that was introduced.
Also called
- peak and trough
- peak
- trough
- peak-trough
- trough level
- cmax
- tmax
- cmin
- peak concentration
Cmax is the peak concentration and Tmax the time at which it occurs; Cmin is the trough. The C stands for concentration and the T for time.
Compounds carrying this term
None on file yet. This term is in the controlled vocabulary but no compound record currently uses it — which is a statement about our coverage, not about the term.