why the time that drugs like caffeine affect you are measured with “half life” regardless of the amount ingested rather than a constant rate

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Does the body not clear drugs like caffeine at a constant rate? If you drink less caffeine does the body clear it less quickly? Or am I not understanding it? Caffeine half life is about 5 hours (via Google), so regardless of if I drink 100mg or 900mg of caffeine, half (50mg or 450mg) will be left in my body 5 hours later? That seems like a pretty drastic difference in the rate of clearance.

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Anonymous 0 Comments

It’s not just drugs. Most concentrations of substances reach homeostasis at a logarithmic-ish rate across semi-permeable membranes.

There are certain constant rates that you can use to approximate your metabolism. For example, it takes roughly one hour to metabolize a single serving of alcohol. This isn’t exactly true, but it’s close enough to effectively pace your consumption.

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