Peptide Half-Life Calculator

Does this tell me how long effects last, or when I’ll pass a drug test?

No. This calculator estimates plasma clearance only — how much of the compound is mathematically modeled to remain in blood plasma over time, based on its published half-life. Biological effects can outlast plasma levels, and lab/urine drug-test detection windows depend on assay sensitivity and metabolite behavior, not plasma concentration. This is not a drug-test or detection-window tool.

What does "half-life not established" mean?

It means PeptideBase does not have a reliable, quantified pharmacokinetic half-life on file for that compound — the recorded value is qualitative (e.g. "varies by component") or missing. We never fabricate a number to fill the gap; the calculator shows the compound’s actual recorded text instead of a curve.

Why does the chart show a range instead of one line for some compounds?

Many published half-lives are themselves a range (e.g. "5–7 days"), reflecting real variability in the underlying studies. The calculator shows both bounds as a shaded band — a solid line for the slower (longer) half-life and a dashed line for the faster (shorter) one — rather than collapsing a real range into one misleadingly precise number.

Is this model accurate for every route of administration?

No. This assumes a single-dose, single-compartment first-order decay from one published half-life value. Real pharmacokinetics are multi-compartment, vary by individual, and can differ substantially by route (e.g. IV vs. subcutaneous) — when a compound’s source text specifies a route, that is noted, but this remains an educational approximation, not individualized dosing guidance.