Loading Dose

A loading dose is a higher-than-maintenance initial dose used to bring plasma concentration to its target level faster than would be possible by waiting for steady-state accumulation at the maintenance dose. Loading doses are most relevant for compounds with long half-lives, where unaided steady-state would take many weeks.

In peptide research, TB-500 protocols sometimes specify a higher dose during the first 4–6 weeks (loading phase), followed by a lower maintenance dose. Some longevity protocols use a similar pattern: higher dose during the active induction window, lower dose for maintenance.

Loading is not appropriate for every compound. For GLP-1 agonists like semaglutide and tirzepatide, the standard practice is the opposite: titrate up slowly to reduce GI side effects, even though steady state takes longer.