Half-life implications for missed doses — May 2025

This one has a reasonably settled answer, so here it is. The mechanism is more central than most summaries suggest. Receptor agonism in the arcuate nucleus activates POMC neurons and inhibits AgRP/NPY signalling, and the downstream MC4R pathway is the same one disrupted in monogenic obesity — convergent genetic evidence that the target is the right one. Peripherally there is glucose-dependent insulin secretion, glucagon suppression and delayed gastric emptying, but the gastric component largely adapts over months while the central effect persists, which is why the durable effect is appetite rather than fullness.

Dr.AddMedPHL said:

The mechanism is more central than most summaries suggest.

Agreed, and the adaptation point cuts both ways: tachyphylaxis to gastric emptying is why tolerability improves, and it is also why people who were relying on physical fullness feel the effect fade while the appetite effect is still working.

pat_auckland said:

I was three days late with a dose because of travel and then spent a week unsure whether I had reset something or simply shifted it.

Second this. The detail I would add is minor and it is already implied above.

Adding the clinical framing, because it changes how the question reads.

Missed dose question about a missed dose: I'm 2 days late on my injection. Should I take it now or wait until my regular day?

UPDATE: Called my provider — they said take it now and resume my regular schedule next week. Apparently being a few days late isn't a big deal as long as you don't double up.