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CyclePlotter
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How the model works

Every dose rises to a peak anchored to a published study, then decays. The plotter sums all of them, day by day. Here is exactly what it does and where it stops.

Rise to a measured peak, then decay

An injection does not reach its peak the moment it is given. It rises over hours or days as the ester is cleaved and the hormone enters circulation, and only then starts to fall. Where a study reports how high a dose peaks and how long it takes to get there, the plotter uses those two numbers directly.

Serum concentration curve for a single 250 mg dose of testosterone cypionate, rising to a peak at 4.5 days then decaying
250 mg testosterone cypionate, peak at 4.5 days, 30 days shown

cmaxPerMg is the peak serum concentration per milligram injected, read from the study. Because it was measured in blood, the ester weight and everything else the body does on the way in are already inside it. The result is an estimate in ng/dL rather than a count of milligrams.

That peak is then rescaled so that esters of one hormone agree about total exposure per milligram, for the reason set out below. So the height of the curve is anchored to the measured peak rather than equal to it: enanthate is plotted below the figure its study reports, and the number the chart is faithful to is the area under the curve, not the top of it.

Not every compound has been through that kind of study. Where no peak has been published the curve shape is inferred from the half-life alone and the level is calibrated instead, which the plotter marks as an estimate wherever it shows one.

peak = dose * cmaxPerMg * multiplier

rising, t <= tmax
  peak * (1 - e^(-ka * t)) / (1 - e^(-ka * tmax))

falling, t > tmax
  peak * e^(-ke * (t - tmax))

ke = ln(2) / halfLife
ka = 3 * ln(2) / tmax
concentration from one dose at day t, in ng/dL

Why levels keep climbing after the first injection

Past its peak a dose falls by half each half-life: three quarters gone after two, about 97% gone after five. If the next dose lands before that, what is left stacks underneath it. Levels keep rising until what you clear each day matches what you add.

That crossover point sits at roughly five half-lives. For a 24 hour compound it arrives inside a week. For a 10 day ester like nandrolone decanoate it takes about seven weeks, and for testosterone undecanoate in castor oil closer to six months — longer than many cycles run, so the curve never actually flattens.

Why the ester changes the shape, not the height

Testosterone is testosterone whether it arrives on a propionate or an enanthate. The ester changes how fast it is released, not how fast the body clears it once it is there. So at the same weekly dose, a short ester and a long one settle at close to the same average level. What differs is the swing: propionate saws up and down between injections, enanthate holds a flatter line.

That is a constraint, and the plotter enforces it. Every ester of a compound is calibrated so the total exposure per milligram of hormone delivered comes out the same across the family. Without it, a long ester picks up accumulation with nothing pulling its peak down and ends up looking several times stronger than the short ester at an identical weekly dose, which is not what happens.

What this model does not do

It is an estimate, not your bloodwork

Where a figure has a source it is usually a study of a small group of people, and thirteen of the compounds here have no published source at all. Metabolism, body composition, injection site, oil carrier, age and genetics all move the real number, and the spread between individuals is wide. Every compound page names its reference, or says plainly that there is not one. Nothing here replaces a blood test.

Some compounds have no measured peak

Where no study reports a peak concentration, the curve shape is inferred from the half-life alone and the level is calibrated rather than measured. Those compounds are marked as estimates in the plotter, and their level is the least reliable part of the chart.

Concentration is not potency

Two compounds sitting at the same level on the chart do not do the same thing. Receptor affinity, androgenic to anabolic ratio, aromatisation and tissue selectivity are all outside this model. Comparing heights across different compounds tells you very little.

Clearance is assumed not to change

Adding every dose together assumes the body clears the compound at the same rate in week twelve as in week one. It does not. Anabolic steroids suppress SHBG, the protein that binds most of the testosterone in circulation, and only unbound hormone is cleared, so the clearance rate drifts upward over a long run. Levels late in a long cycle read higher on the chart than they would in blood.

It says nothing about safety or results

The plotter has no opinion on what you enter. A curve that looks smooth is not a curve that is safe, and the model cannot flag anything as a good or bad idea.

References

Each compound is plotted from its own reference, named on its page. The papers below are the ones behind the model itself — the clearance figure the whole chart is scaled against, and the reason a depot ester's half-life is not the half-life of the hormone.

The same equation runs across all 33 compounds in the reference.

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