Half-life, one half at a time.
A visual introduction to exponential decline, what a half-life means and what a simple curve leaves out.
Published version 1Half-life, visualized.
Each half-life halves the starting quantity.
Illustrative model, not a dosing schedule.
Model details & study source
A 2022 phase 1b Retatrutide study reported an approximate six-day half-life. This is a normalized, single-elimination teaching model, not measured blood levels, a clearance guarantee, an efficacy curve or a dosing schedule. Absorption and individual pharmacokinetics are not modeled. Read the original study
Overview
What the curve means. In a simple first-order elimination model, one half of a starting quantity remains after one half-life, one quarter after two and one eighth after three. The horizontal axis counts half-lives; the vertical axis is a normalized percentage, not a prescribed amount.
Further context 2
A study provides context. A 2022 phase 1b study in adults with type 2 diabetes reported an approximate six-day half-life for retatrutide, then called LY3437943. A population estimate does not describe every person or every formulation.
Further context 3
What it cannot tell you. A simplified elimination curve does not model absorption, repeated administration, individual organ function or therapeutic response. A small remaining modeled fraction is not proof that a substance is fully cleared or that a particular interval is safe.
General education. Discuss personal medical decisions with a qualified clinician.