Peptide Half-Life & Decay Calculator
Calculate active remaining compound levels over time, half-lives elapsed, clearance percentages, and elimination timelines.
Pharmacokinetics & First-Order Elimination Math
Written out so you can check it by hand. The app runs this exact function — not a second implementation that drifts.
Peptide clearance typically follows first-order elimination kinetics, where a constant fraction of compound is cleared per unit of time.
1. Exponential Decay Formula: N(t) = N₀ × (0.5)^(t ÷ t½), where N₀ is the initial dose, t is elapsed time, and t½ is the elimination half-life.
2. Half-Lives Elapsed: Half-Lives = Elapsed Time ÷ Half-Life Duration. After 2 half-lives, 25% remains (75% eliminated). After 3 half-lives, 12.5% remains.
3. Clearance Thresholds: 50% elimination occurs at 1 half-life; 90% elimination occurs at ~3.32 half-lives; 99% elimination occurs at ~6.64 half-lives.
The number is right. Now keep the record.
Save doses, set reminders, and keep the math in one place. The calculators stay free either way.