Peptide half-life calculator
Pick a peptide (or enter any half-life) to see how much remains over time, when it effectively clears, and how it accumulates to steady state on a repeating schedule.
Inputs
Results
Clearance
- 1 half-life (30 min)50.0% left
- 2 half-lives (1.0 h)25.0% left
- 3 half-lives (1.5 h)12.5% left
- 4 half-lives (2.0 h)6.3% left
- 5 half-lives (2.5 h)3.1% left
Effectively cleared (~97%) after 2.5 h.
Remaining over days
- 6.0 h<0.1%
- 12.0 h<0.1%
- 24.0 h<0.1%
- 2.0 days<0.1%
- 3.0 days<0.1%
- 5.0 days<0.1%
- 7.0 days<0.1%
- 10.0 days<0.1%
Steady state
Peak levels build to about 1.0× a single dose, reaching ~90% of steady state after 1.7 h.
How the math works
- remaining = 100% × 0.5^(t / half_life) — first-order (exponential) elimination.
- time to X% = half_life × log₂(100 / X)
- A drug is usually considered effectively cleared after ~5 half-lives (≈3% remaining).
- steady-state ratio = 1 / (1 − 0.5^(interval / half_life)) — how much peak levels build up with repeated dosing.
Half-lives are population estimates from the research literature and vary by individual, route, and formulation. This is a first-order model — real pharmacokinetics can be multi-compartment.
Not medical advice.
An educational math tool for research logging only. Consult a licensed physician before making any decisions about your health.