Dose Timing
Peptide dose timing & steady-state visualiser
Visualise documented dosing protocols only, accumulation curves, peak/trough levels, and time-to-steady-state read directly from each peptide's published cadence. No schedule is generated from half-life math except as a labelled last-resort fallback.
The formulas
- Accumulation ratio = 1 / (1 − 0.5(τ/T½)), peak / single-dose-peak at steady-state
- Trough ÷ peak = 0.5(τ/T½), fraction of steady peak retained at end of interval
- Time to 95% steady-state ≈ 4.32 × T½ (= log2(20) × T½)
τ = dose interval; T½ = half-life. For τ = T½, accumulation ratio = 2. For τ = 0.5·T½ (twice per half-life), ratio ≈ 3.4. Sparser dosing (τ ≫ T½) collapses ratio toward 1.
Worked example, Tirzepatide, 2.5 mg SC weekly, T½ ≈ 5 days
- τ / T½ = 168 hr / 120 hr = 1.4
- Accumulation ratio = 1 / (1 − 0.51.4) ≈ 1.61×, steady peak ≈ 1.6 × first-dose peak
- Trough / peak = 0.51.4 ≈ 0.379, 38% retained at end of week
- Time to 95% SS ≈ 4.32 × 5 d = 21.6 days ≈ 3 weekly doses
What this tool does not do
- Does not generate a cadence from half-life. The calculator reads cadence from each peptide's documented dosage string and refuses (or surfaces an explicit "educated guess" disclaimer) when ambiguous.
- Does not model absorption (Bateman / two-compartment PK). Single-compartment first-order decay between doses; t = 0 of each dose is peak.
- Does not adjust for body weight, BSA, or individual variability. Where the dosage uses mg/kg or mg/m², a small-adult / large-adult range is shown and labelled as inferred.
- Does not recommend, suggest, or validate any schedule. Use only for visualisation.
Arithmetic only. This view does not suggest, recommend, or validate any dose, schedule, or washout window. Consult a qualified clinician before any human use.
Open the interactive PeptideHelper.org dose-timing visualiser to overlay up to four peptides on a shared 7/14/28/56-day timeline.
Frequently asked questions
How long does it take a peptide to reach steady-state?
About 4 to 5 half-lives of consistent dosing. The time-to-95%-steady-state benchmark is 4.32 × T½ (= log₂(20) × T½). For a peptide with a 5-day half-life dosed weekly, that is roughly 21.6 days or about 3 weekly doses.
What is the accumulation ratio formula?
Accumulation ratio R = 1 / (1 − 0.5^(τ/T½)), where τ is the dose interval and T½ is the half-life. R is the multiplier from single-dose peak to steady-state peak. For τ equal to one half-life, R = 2. For τ much greater than T½ (sparse dosing), R approaches 1.
What is the difference between peak and trough?
Peak (Cmax) is the highest concentration in a dosing interval; trough (Cmin) is the lowest, immediately before the next dose. At steady-state, trough = peak × 0.5^(τ/T½). Long half-life vs short interval gives a high, shallow plateau; short half-life vs long interval gives spiky peaks separated by near-zero troughs.
Does this calculator generate a cadence from half-life?
No. The cadence is read from each peptide\u2019s documented dosage string in the data. Where the string is ambiguous (frequency range, IU units without conversion, capsule strength not stated, etc.) the calculator either makes an explicit educated-guess inference and surfaces a disclaimer, or refuses to draw a curve. Half-life-only fallback only fires as the last resort and is labelled "EDUCATED GUESS, NOT A DOSING RECOMMENDATION".
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