Per-substance profiles
Each profile has a half-life calculator, comparison context, an editorial read, and links back to source material. The pages are built to answer “what does this number mean?” before a reader overuses it.
PK-aware tools
Substance half-life made visual.
Choose a substance and an elapsed time. HalfLifeDB turns source-linked half-life estimates into a readable curve, then surrounds the number with the context a careful reader needs.
Search 18 reviewed profiles
research, Rx, everydayStart with something common like MDMA, cocaine, nicotine, or caffeine, or explore medications and nonmedical substances by category. Each published entry has a normalized curve, source notes, and clear limits.
Browse: all substances · compare curves · Learning Center
Published profiles18Substance pages with calculators, source context, and editorial notes
Categories10Navigation groups for browsing related entries
Reference links62Primary, database, labeling, and literature links
What HalfLifeDB does well
HalfLifeDB focuses on one narrow job: make half-life easier to see, then make the limits of that visual hard to miss.
Simple elimination curves
The calculator applies a one-compartment first-order elimination model. Every half-life interval, the model halves the remaining amount and plots the curve. It is intentionally simple, then clearly labeled where real pharmacokinetics can be more complicated.
How pages are built
The site is intentionally narrow: explain half-life, show the math, disclose uncertainty, and link readers back to source material.
Transparent model
Each calculator uses the same first-order equation, displays the half-life value used, and explains what the curve can and cannot tell you.
Source context
References are shown on each profile. A numerical curve is published only when labeling, a human study, or a focused review supports the selected value; identity databases are treated as background, not proof.
Explicit limits
HalfLifeDB does not provide dosing guidance, treatment advice, impairment estimates, or instructions for laboratory testing. Those boundaries are repeated across the site.
Start with concepts
These explainers make the calculator easier to interpret before looking up a specific substance.
What half-life means
A plain-language explanation of the term, the 50% concept, and why a half-life number is not a safety claim.
Half-life vs duration
Why subjective effects can fade before elimination is complete, and why some downstream effects can last beyond the parent compound.
Why estimates vary
A checklist of study design and person-to-person factors that can shift reported pharmacokinetic values.
How to read studies
A practical guide to scanning pharmacokinetic papers for population, route, analyte, sampling window, and limitations.
Clearance and distribution
Why half-life depends on both removal from the measured compartment and how widely a substance distributes through the body.
Route and formulation
Why oral, inhaled, injected, transdermal, immediate-release, and extended-release sources should not be treated as interchangeable.