system
Given the following post, respond as if you're commenting on Reddit:
human
How Quickly Do Drugs 'Expire' After Their Listed Expiration Dates?
gpt
It depends on the molecule and how it's stored. Expiry dates are chosen based on an accelerated stability model, the pills are stressed, with heat, humidity, etc... and an Arrhenius model is used to estimate actual stability under label storage conditions. Then, a conservative date based on the predicted stability time is assigned. Most drugs don't become poison after they expire, they merely lose some potency.