Half-life is the time it takes for 50% of a compound to be eliminated from the body. After one half-life, 50% remains. After two half-lives, 25%. After 5 half-lives, less than 3.125% remains — generally considered "cleared." Peptides vary widely: BPC-157 has a very short half-life (~30 min), while Semaglutide has a very long one (~7 days).

Steady-state is reached when the amount of compound entering your system equals the amount being eliminated. This typically occurs after 4–5 half-lives of consistent dosing. At steady-state, peak and trough levels stabilize — meaning more predictable effects. GLP-1 protocols often take 4–5 weeks to reach true steady-state.

This tool uses standard first-order elimination kinetics, which models how most peptides behave. It assumes consistent absorption and no drug interactions. Individual variation (body composition, metabolism, kidney/liver function) can shift actual clearance times. Use these numbers as a general guide, not a clinical guarantee. Always verify independently.

Use the preset buttons above for common peptides — they're pre-loaded with published half-life values. General ranges: BPC-157 ≈ 30 min (subQ), TB-500 ≈ 3 days, Semaglutide ≈ 7 days, Tirzepatide ≈ 5 days, CJC-1295 (no DAC) ≈ 30 min, CJC-1295 (with DAC) ≈ 6–8 days, Ipamorelin ≈ 2 hours, NAD+ ≈ short (minutes IV, longer subQ).

This is the estimated time from your last dose until less than 3.125% of the compound remains (5 half-lives). For most research purposes, this is considered functionally cleared. For compounds with accumulation from multiple doses, the calculator accounts for the total residual body burden, not just the last dose.