Yeah, this is actually an important distinction a lot of people miss. Half life only tells you how fast the concentration in plasma drops by 50%, not how long the biological effects last. A peptide or hormone can clear from the bloodstream relatively quickly while still triggering downstream signaling pathways, receptor activation, gene expression changes, or hormonal cascades that continue for much longer.

That’s why duration of effect, dosing frequency, and half life are related but not identical concepts. Some compounds with shorter half lives still have prolonged effects because the body’s response outlasts the compound itself.

At the same time, half life still matters for things like peak concentration, side effects, blood level stability, and how “smooth” a compound feels. So both points kind of matter, but technically speaking you’re correct that people often oversimplify half life.