Marker fragments peak within 2 hours and last up to a day
Collagen is digested into free amino acids and short peptides. The marker fragments peak in blood 1 to 2 hours after a dose and stay detectable for up to 24.
What the study found
Collagen peptides peak in blood at 1 to 2 hours, then linger a day
Collagen has no single half-life the way a drug does. It is digested into free amino acids and short peptides, and the marker fragments peak in the blood 1 to 2 hours after a dose, then stay detectable for up to 24. One tough three-part fragment holds its peak for four hours.
The caveat · Tracks a few fragments, not all
These are absorption curves for a few marker fragments, not a clearance time for the ingredient as a whole. Collagen from different animal sources may behave differently. And finding the tough fragment in blood shows it lasts, not that it does anything while it is there.