Your own GLP-1 hormone is broken down in minutes. The drug versions are engineered to last about a week — here's how that works.
The natural hormone lasts 2 minutes
Your gut releases GLP-1 after every meal. The enzyme DPP-4 in your blood breaks it down almost immediately. That short half-life is why your natural signal can feel weak — it doesn't get a chance to build up.
How drug-makers extended it
Semaglutide and tirzepatide are modified at specific positions on the protein chain so DPP-4 can't grab them. Add a fatty acid tail and the molecule binds to albumin in your blood, which lets it travel slowly through the kidneys — extending the half-life to roughly 7 days.
What this means for you
Once-weekly injection gives a steady drug level all week, instead of peaks and troughs from daily dosing. That's part of why side effects are usually milder than older diabetes drugs.
