Methodology

What the chart shows

The chart shows the estimated amount of a drug still in the body, in milligrams (IU for compounds dosed in IU). For an ester, that is the amount of the parent hormone, after the ester weight is taken out.

It is not a blood level, and it will not match a lab result in ng/dL. Turning an amount into a blood concentration needs each person's volume of distribution, binding proteins such as SHBG, and clearance. All three vary a lot from person to person, and the model has none of them.

The model

Each dose rises in a straight line to its time to peak (Tmax), then halves once every half-life (t½):

activeDose = doseMg × activeFraction

remaining(t) =
  0                          if t < t0
  activeDose × (t − t0)/Tmax if t0 ≤ t < t0 + Tmax
  activeDose × 0.5^((t − t0 − Tmax) / t½)  otherwise

Every later dose is the same curve shifted in time, and the chart adds them together. That sum is why long esters climb for weeks before they level off.

Worked example

One 200 mg dose of Test E on day 0. The ester share is 72%, so the active dose is 144 mg. Time to peak is 2 days and the half-life is 4.5 days. These are the values the plotter draws:

Stats under the chart

• Peak is the high point in the last dosing interval, including the rise after the last dose.
• Trough is the amount left at the last dose, just before it rises.
• Swing is (peak − trough) ÷ peak.
• Steady state is read off the curve: the first dose whose trough is within 3% of where the schedule settles.
• Washout is the time after the last dose until the amount falls to 3% of its final peak.
• The line that adds all compounds together has its stats read from the last week of dosing. Compounds are not equally strong per mg, so it shows timing and swing, not total strength.

Where the numbers come from

Every compound lists its sources, and each source is one of 4 kinds. The last column counts how many of the 37 listed compounds take their half-life from that kind.

1 plotted half-life is not stated by any single source, because the sources disagree: Test C. The compound page explains why.

Each compound also gets a data-quality grade:

• High: a label for this product and route gives the number (9 compounds).
• Medium: a paper or a partial label gives the number (7 compounds).
• Low: the number is a community estimate, or the sources conflict (21 compounds).

Each compound page lists its sources in full, with the exact figure and where it appears. The catalog table below links to them.

How ester weight works

An ester is the hormone with a fatty acid chain attached, which slows its release from the injection. The chain has weight but no hormone, so part of every milligram is the ester. PubChem lists testosterone at 288.4 g/mol and testosterone enanthate at 400.6 g/mol. So 100 mg of testosterone enanthate is about 72 mg of testosterone (288.4 ÷ 400.6).

The plot multiplies each dose by that share, which the catalog table calls the share that is parent. Orals, GLP-1s, and peptides are not esters, so the table shows a dash for them.

Known limits

• One compartment only: no volume of distribution, so no ng/dL.
• No SHBG, aromatization, non-linear peaks, or individual metabolism.
• Absorption differs with the injection site, the carrier oil, and the volume injected. The model uses one average curve.
• Orals lose part of each dose in the liver before it reaches the blood (first-pass metabolism). The plot shows the amount taken, not the amount absorbed.
• GLP-1 dose steps come from the product label. They are shown to explain timing, not as a schedule to follow.
• Half-lives are population averages. Yours can be shorter or longer.

Corrections and changes

We check the cited label or paper, update the number and the date on the page, and note the change on the methodology page. Send a correction with its source to austin@buildleansaas.com.

Data changes