Washout calculator

How long after the last injection until a compound has effectively cleared. The curve starts from the level you were actually at, which depends on your dose and how long you had been on it, not from a single dose in isolation.

Effectively clear after 57 days
Level at last dose 11.48 mg
Half life 6 days
Threshold used 0.02 mg
Amount remaining after the final injection, milligrams.
0.0 5.0 10 15 20 w0w2w4w6w8w10w12

x weeks since the last injection y milligrams in body

Milestones

Each row is the point at which the level has fallen to that fraction of where it started.

RemainingAmountDays after last dose

What "clear" means here

The threshold is 0.02 mg, which is a display convention rather than a clinical one. Elimination is exponential, so the amount never reaches exactly zero; it halves at a fixed interval forever. Any washout figure is therefore an answer to "below what number", and we state ours rather than hiding it.

Starting level matters more than people expect. Someone stopping after four months at a maintenance dose has accumulated far more than someone stopping after two injections, so their curve starts higher and takes longer to fall, even though the half life is identical.

This models the compound only. How long an effect lasts is a different question, and not one arithmetic can answer.