Enzyme effects

Two people on the same dose of the same drug get different plasma curves. Enzymes are the biggest reason why.

Why enzymes vary

• Genetics — CYP2D6, CYP2C19, CYP3A4 polymorphisms (poor / intermediate / extensive / ultra-rapid metabolizer)
• Sex — CYP3A4 baseline is higher in females
• Age — most enzymes slow after 65
• Liver disease — Child-Pugh score reduces overall activity
• Inducers + inhibitors — other drugs on your timeline; effects compound

How Lab models this

• Each compound has a documented enzyme breakdown — the share of clearance handled by each enzyme.
• Lab applies your profile-specific multipliers to each enzyme's baseline activity.
• Other timeline items can induce or inhibit those enzymes; Lab compounds the effect over time.

The enzyme detail panel

Anywhere an enzyme is named — Clearance section, Effects on other drugs, the sidebar — its name is a clickable chip. Clicking opens the enzyme detail panel, which replaces the inspector view with:

• Live activity — the multiplier at the current playhead (1.00 = your personal baseline)
• Sparkline — how the activity has evolved across the full simulation
• How it's composed — every modifier pushing the activity above or below 1.00 (genetics, sex, age, liver function, plus every active inducer / inhibitor)
• Active modulators — every timeline item currently shifting this enzyme, click-through to that item

Use the back arrow to return to the inspector view of the original compound.

Why the multiplier matters more than the raw value

The engine doesn't ask you to learn what "normal CYP3A4 activity" looks like in absolute units. Instead, it expresses every enzyme as a multiplier on your personal baseline:

• 1.00 = your normal activity for this enzyme
• 1.50 = 50% faster than your normal
• 0.50 = half your normal speed

This makes the chart immediately readable: anything above 1.00 means a co-administered drug is inducing the enzyme; anything below means something is inhibiting it; the further from 1.00, the bigger the effect on every drug that enzyme clears.