Half-life and levels calculator
Pick a compound, enter your dose and how often you take it. The chart shows how your estimated level builds up, where it settles, and how far it dips before each dose. It runs in your browser: nothing is sent anywhere.
Each dose counts in full when you take it, then halves every half-life. Add up every dose and you get the curve. Levels settle once you're losing as much between doses as each dose adds: about 5 half-lives in.
This shows the shape, not your blood test. Absorption, your body and the product itself all change the real numbers.
For planning only. Your prescriber sets your dose.
Half-life by compound
Questions
How is the estimated level worked out?
Each dose is counted in full on the day it's taken and then halves every half-life. Adding up every dose gives the curve. It's the same model the app uses for its estimated levels chart.
Is this my blood level?
No. It shows the shape: how levels build up, settle, rise and fall between doses, and wash out. Real blood levels also depend on absorption, your body and the product itself. Use a blood test for your actual level.
Why split a weekly dose into smaller injections?
The weekly average stays the same, but smaller, more frequent doses make the peaks lower and the dips shallower. The table under the chart shows how much for your half-life.
How long until levels settle?
About 90% after 3.3 half-lives and close to fully after 5, whatever the dose. For testosterone cypionate (about 8 days) that's roughly 4 weeks to mostly settle and 6 weeks to fully settle.