In one line: the curve is a simplified educational illustration of how a compound might rise and fall based on published half-life estimates and the doses you have logged. It is not a measurement of the level in your body and must never be used to make dosing or medical decisions.

What the curve shows

Each time you log a dose, the app treats it as an amount that enters your system at that moment and then decays over time. It adds together the contribution still remaining from every dose you have logged in the window, and plots the running total.

The vertical axis is relative — the whole curve is scaled so its highest point over the window reads 100%. It shows the shape of the rise and fall and the relative difference between peaks and troughs. It is deliberately not expressed in ng/mL or any real concentration unit, because the app has no way to know your true blood level.

The model

We use a one-compartment exponential-decay model with superposition — the standard textbook first approximation for how a substance clears from the body. Each dose decays according to its half-life, and overlapping doses add together:

level(t) = Σ doseᵢ × 0.5 ^ ((t − tᵢ) / t½) summed over every logged dose i with time tᵢ ≤ t, where t½ is the compound’s half-life. The final series is then normalised so the peak over the window = 100%.

Assumptions baked in

Where the half-lives come from

The half-life for each compound is an approximate literature estimate drawn from published pharmacology and manufacturer data. Reported values often vary widely between sources, studies and individuals, so we use a single representative figure per compound for illustration. A few examples of the values in the model:

CompoundApprox. half-life usedClass
Semaglutide~7 daysGLP-1 / metabolic
Tirzepatide~5 daysGLP-1 / metabolic
Retatrutide~6 daysGLP-1 / metabolic
BPC-157~4 hoursHealing / repair
TB-500~2–3 daysHealing / repair
Ipamorelin~2 hoursGH secretagogue
CJC-1295 with DAC~7 daysGH secretagogue
Illustrative subset of the values in the model. Figures are rounded literature estimates for educational display only and should not be read as precise or authoritative pharmacokinetic data.

Where we don’t hold a reliable half-life for a compound (including many custom compounds you add yourself), the app simply does not draw a curve rather than guess.

Limitations — please read

Important. My Body Optimise is an informational tracking and logging tool for personal use. The estimated-levels feature is an educational illustration produced by a simplified mathematical model; it does not provide medical advice, diagnosis or treatment, and does not measure any substance in your body. In the UK, many peptides are unlicensed research compounds and are not MHRA-approved medicines. Always consult a qualified healthcare professional before making any decision about your health.