Choose a common compound or enter your own half-life. The tool plots an exponential decay curve over five half-lives and shows how long it takes to fall to 50%, 25%, 10% and 5% of the starting amount, plus a note on steady-state accumulation for repeat dosing.
Educational tool — not medical advice. Half-life figures are approximate literature/community values for general reference and vary by source, individual physiology and assay. This tool only models exponential decay from the number you select or enter; it does not recommend any dose, compound, schedule or protocol. The peptides referenced are research chemicals not approved for human use by the FDA or any major regulator. Always consult a licensed healthcare professional. See our full disclaimer.
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A half-life is the time for the amount of a substance in circulation to fall by half. Because each half-life removes the same fraction (not the same amount), the decline follows an exponential curve — fast at first, then ever slower.
That is why the milestones land where they do: 50% after 1 half-life, 25% after 2, about 10% after 3.32, about 5% after 4.32, and under 1% after roughly 6.6 half-lives — the point most pharmacology references treat as functionally cleared.
Repeated dosing. If a compound is re-dosed before it fully clears, levels build up until the amount cleared each interval equals the amount added. The shorter the interval relative to the half-life, the higher this plateau. The accumulation factor above estimates the trough multiple versus a single dose, and it generally takes about five half-lives to approach that steady state.
Approximate values for general reference only; sources and individuals vary. Many peptides have a short circulating half-life yet far longer tissue or biological effects — see each compound's full guide for nuance.
| Compound | Approx. half-life (this tool) | Note |
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Turn vial size, water and dose into concentration and syringe units.
ToolConvert between mg, mcg, mL and U-100 syringe units for any concentration.
GuideThe science of pharmacokinetics, tissue persistence and dosing frequency.
ReferenceA side-by-side chart of published half-lives across common peptides.