Half-life & dosing calculator
How long a peptide stays bioactive is governed by its half-life — and how repeated doses build up depends on how the dosing interval compares to that half-life. Enter a half-life and an interval to see how long a single dose persists, how much repeated dosing accumulates, and how the concentration rises and falls over a schedule.
A one-compartment, first-order model. “Dose” is relative — results scale with whatever amount you enter. Find a compound’s half-life via the research agent or the literature.
How long one dose stays active
Bioactivity over the schedule
Tighter intervals relative to half-life accumulate higher and fluctuate less; wide intervals barely accumulate and swing more. Concentration math only — not medical or dosing advice.
The pharmacokinetics
Half-life (t½) is the time for the amount in the body to fall by half. After one half-life 50% remains, after two 25%, and after about five half-lives roughly 97% is gone — the common rule of thumb for when a single dose is effectively cleared.
Accumulation happens when the next dose arrives before the last is gone. The ratio of the dosing interval to the half-life sets everything: dose often relative to the half-life and levels climb to a high, stable plateau with little swing; dose rarely, so each dose largely clears before the next, and levels barely accumulate but fluctuate widely.
Steady state — where input balances elimination — is reached after roughly four to five half-lives regardless of how often you dose. Dosing more frequently raises the plateau; it does not arrive sooner.
Not sure of a compound’s half-life? Ask the research agent, which can surface values and trials from the literature.
A simplified one-compartment model for understanding pharmacokinetic behavior. Real compounds have absorption phases, multi-compartment distribution, and nonlinear clearance this does not capture. Educational only — not medical advice, dosing guidance, or a recommendation to use any substance.