About this calculator
Who the numbers came from, how strong each of them is, and what this model refuses to do. A reference you cannot audit is not much of a reference.
What this site is
CyclePlotter is a free, independent calculator that models the serum concentration of anabolic compounds over time. It is not a shop, it does not sell anything, it has no affiliate links and it takes no sponsorship. There is no account, and cycles you build are written to your own browser rather than to a server.
It exists because the arithmetic it does — accumulation across overlapping doses of compounds with different half-lives — is genuinely hard to do in your head and easy to get wrong on paper, and because the alternative most people use is a forum post quoting a number with no source attached.
Where the numbers come from
Every compound carries a terminal half-life and, where one has been published, a peak concentration and a time to peak. 15 of the 33 compounds modelled are anchored to a published Cmax and Tmax; the rest have a half-life only, and their curve height is calibrated against related compounds rather than measured. 20 carry a citation you can open and read for yourself, linked on the compound's own page.
Where a figure is weak, the page says so in the place you would read it, not in a footnote. Compounds with no published peak are marked estimated; the handful with no published reference at all are marked as such and described as the least reliable in the set.
How the model works
Each dose rises to a peak and then decays exponentially at the compound half-life, and the plotter sums every active dose for each day of the cycle. Doses are made comparable across a hormone family by normalising area under the curve per milligram of hormone delivered, because clearance is a property of the hormone rather than of the ester carrying it.
The full method, the equations and the papers behind them are set out in detail rather than summarised.
What it deliberately does not do
It does not recommend a compound, a dose, a length or a protocol, and it has no default cycle. It makes no claim about what any compound does — the copy on this site stays inside what the pharmacokinetics support, which means release rate, accumulation and clearance and nothing else.
It also does not model metabolites, so nothing here estimates a detection window, and it is not a substitute for bloodwork or for a doctor.
Corrections
The compound tables are the part most likely to be wrong, and the kind of wrong that is hard to see from the outside. If a half-life here disagrees with a paper you have, that is worth knowing about — a citation is enough to act on.
Figures are checked against their sources periodically, and the review date below is the last time that happened.