Terms of use

What this site is

Still In My System is a free calculator that applies a standard exponential decay formula to a published half-life value. It gives you a mathematical estimate, not a measurement, a prediction, or a medical opinion.

Not medical advice

Nothing on this site is medical advice, and using it does not create a doctor-patient or any other professional relationship. Do not use this calculator to decide when to take a dose, whether a medication has "worn off," whether it is safe to drive, or any other health or safety decision. If you have questions about a medication you are taking, ask your doctor or pharmacist, who can account for your specific health history, other medications, and how your body actually processes things — none of which this calculator can see.

Accuracy

Half-life values are drawn from sources such as FDA prescribing information and peer-reviewed pharmacology literature, with the specific source noted on each substance's page. Real-world half-life varies by individual (age, weight, organ function, genetics, other medications, and more), so the number this calculator gives you is a population-average estimate, not your personal result. We try to keep the underlying data current and correct, but we make no guarantee of accuracy and aren't liable for decisions made based on this tool.

Advertising

This site is supported by Google AdSense. Ads are served by Google and its partners and are not endorsements by us of any product or service shown. See our privacy policy for details on how advertising cookies work here. Privacy policy

Changes

We may update these terms as the site changes. Continued use of the site after an update means you accept the revised terms.