the.com/side effect
the fine print your body reads whether you agreed to it or not.
means an unintended consequence of a treatment or action, riding along with the effect you actually wanted.
from from pharmacology, where drugs rarely hit one target and leave the rest of the body alone; the phrase migrated into everyday use for any unplanned consequence of doing something on purpose.
aspirindiscovered blood-thinning effect first, painkiller marketing came later
viagrabegan as a failed heart medication trial
minoxidilblood pressure drug that grew hair as a side effect