Pharmacokinetics, made visible

See how long it actually stays in your system

A visual half-life and clearance tool for every performance and enhancement compound. Read your own levels over time instead of guessing at them. Free to start.

Start modeling free
Free to join. 18+. Education only, never dosing or sourcing.
Half-life, made visible Live demo
Testosterone Enanthate · serum level over time
Dose every 7 days

Why half-life matters

One number tells you how a compound behaves over time.

Build-up and steady state

Levels climb dose after dose until what goes in equals what clears. A long half-life builds slowly to a smooth, steady level; a short one is fast on, fast off.

Swing and side-effects

Many side-effects track the peaks and troughs, not the average. Seeing the swing between doses is how you reason about timing instead of guessing.

Washout

Half-life also sets how long something lingers after the last dose, which is what matters for stacking, breaks and clearing out.

Compare on equal footing

Two compounds at the same dose behave completely differently if their half-lives differ. The visualizer makes that visible at a glance.

Inside the visualizer

Model any compound the way you would actually run it. Here is a weekly testosterone enanthate protocol, pulled straight from the tool.

Every dose on one timeline
Testosterone enanthate concentration curve rising to steady state over eight weeks
Watch levels climb dose after dose until they settle into steady state, the same shape published pharmacokinetics predict.
The numbers that matter
Readout cards: peak to trough, anabolic and androgenic load, modeled estradiol
Peak-to-trough swing, anabolic and androgenic load, and a modeled estradiol figure, all updating live as you change the dose or the spacing.
See the side that bites
Estradiol side-marker curve plotted alongside the compound
Estradiol, prolactin and glucose plotted next to the compound, so you can see what rises with it, not just the drug on its own.

The course comes with it

Reading your levels is half of it. The other half is knowing what the numbers mean and what to do when something is off.

Lessons you actually touch
Interactive estradiol window lesson with a draggable level slider
Interactive lessons like the estradiol window, where you drag the level and see for yourself why lower is not better.
28 modules, safety core free
Course module grid with free and full-access modules
Harm reduction, emergencies, bloodwork and recovery are free for everyone. Full access opens all 28 modules and every badge.

Start free. Open the full instrument when you want it.

The free tier is a complete tool on its own. Pro opens the full visualizer and the entire course.

Free
  • Harm reduction and emergency response, open to everyone
  • Model how any compound rises, peaks and clears
  • Peptides, GLP-1s, supplements and hydration
  • Single-compound modeling, steady and ramping
  • Per-compound active-window sliders
  • The Foundations modules in the app
Start modeling free
Pro · $39.99/mo or $399.99/yr

Everything in Free, plus:

  • Full multi-compound stacking on one timeline
  • Estradiol, prolactin and glucose plotted next to the compound
  • Peak-to-trough swing with anabolic and androgenic load readouts
  • All 28 course modules
  • Every badge
Open Pro
Half-Life Lab is an educational tool for pharmacokinetics and risk literacy. It models half-life and clearance curves only. It does not provide dosing instructions, protocols, sourcing, or where-to-buy information. You must be 18 or older. Nothing here is medical advice. Membership and payments are handled on Whop.