Know your
actual window.
Not a guess.
A free, pharmacokinetics-based calculator that tells you when you're genuinely clear — and exactly what to do when you're not. Built for people navigating a system that wasn't designed fairly.
How it works
Clearance Calculator
excretion Start daily psyllium fiber (5–7g) to interrupt enterohepatic recirculation.
avoid No intense exercise — keeps lipolysis low and metabolite release stable.
excretion Light walking only — no cardio, no weights.
diet Eat normally. Caloric restriction triggers lipolysis and spikes metabolite release.
excretion Continue evening fiber.
confirm Test with a home strip. Negative = you may not need the full flush. Positive = run full protocol.
Shopping list
Every ingredient explained by mechanism — not marketing. All available at Amazon, Walmart, or your local pharmacy. Generic versions work equally well.
The science
Fat-soluble metabolites
THC itself converts quickly in the liver to THC-COOH — the glucuronide conjugate that drug tests detect. Because THC-COOH is fat-soluble, it deposits in adipose tissue, the liver, and brain lipids. It releases back into the bloodstream slowly during lipolysis, then gets excreted renally. This is why body fat percentage is the single most important variable in your clearance window.
The confirmation gap
Workplace immunoassay screens (EMIT) use a 50 ng/mL cutoff. If you test positive, the sample goes to GC-MS confirmation — which has a 15 ng/mL cutoff and is nearly impossible to manipulate. Most commercial detox products and calculators only target the immunoassay screen. Threshold shows you both because knowing you'd pass the screen but fail confirmation is critical information.
Lipolysis and the pre-test spike
Aerobic exercise mobilizes fat stores (lipolysis), which temporarily spikes THC-COOH release back into blood and urine. This is counterproductive before a test even though exercise accelerates long-term clearance. Avoiding exercise 24–48 hours before testing and eating fatty foods suppresses lipolysis and reduces the transient concentration spike.
Assay interference
Zinc sulfate taken orally reaches urine and directly interferes with EMIT immunoassay enzyme reagents — the same assay used in most workplace screens. This is mechanistically distinct from dilution and is supported by published literature. It's the most scientifically interesting element of the protocol and the most underutilized. Note: it does not affect GC-MS confirmation.
The policy problem
A positive THC test tells you someone consumed cannabis in the last 2–30 days. It tells you nothing about whether they're impaired right now. Alcohol is tested for current impairment — nobody tests whether you drank last weekend. Blanket THC testing applies a fundamentally different and scientifically indefensible standard.
For safety-sensitive positions — surgeons, pilots, air traffic controllers, heavy equipment operators — impairment testing is justified. For accountants, coders, retail workers, and teachers, the safety rationale evaporates. What remains is insurance pressure and institutional inertia from policies written in the 1980s.
Threshold exists because people navigating this system deserve accurate information. The data generated by this tool will contribute to research and policy arguments for impairment-based standards across all industries.
It will always be free.
The calculator, the protocol, the shopping list — no login, no paywall, no catch. If it helped you, a $5 donation keeps it running and supports drug policy reform. Entirely optional.
Support Threshold — $5 suggested