Glossary term
Half-life
The time it takes for half of a substance to be cleared from the body.
Why it matters
Half-life explains how often something is dosed in research. A long half-life can mean weekly dosing, while a short one can mean daily or more.
If a peptide has a half-life of one week, roughly half of it remains in the body seven days after a dose. Peptides are sometimes modified specifically to extend their half-life so they last longer between doses.