Titration

Titration is increasing a dose in steps rather than starting at the target. A schedule sets a starting dose, a step size, and an interval, and the dose climbs until it reaches the target or until something says stop.

It looks like caution for its own sake. It usually is not.

What the ramp is for

For most compounds where titration is standard, the ramp exists because the side effects arrive before the tolerance does. The GLP-1 receptor agonists are the clearest case: nausea, vomiting and other gastrointestinal effects are strongly dose-related and tend to diminish with continued exposure at a given dose. Going straight to a maintenance dose produces the effects at full strength with no adaptation, and the common outcome is stopping.

The ramp is buying tolerance, not waiting for efficacy. That is why the interval is typically four weeks rather than a few days: it is long enough for adaptation to occur at each step.

A second reason applies for some compounds: finding the lowest dose that achieves the goal. If the effect appears at step three there may be no reason to continue to step five, and every step up usually carries more side effect.

What sets the numbers

For approved drugs the schedule comes from the registration trials and is in the labelling. The steps and intervals used in the semaglutide and tirzepatide trials are the steps and intervals in the prescribing information, because that is the regimen the evidence describes. Deviating from it means leaving the conditions the data was generated under.

Two things follow. Compressing the schedule tends to produce the side effects the schedule exists to avoid. And extending it, holding at a step longer than specified, is generally the safer deviation and is often exactly what a clinician does when a step is not tolerated.

The interval also interacts with half-life. Stepping up before the previous dose has reached steady state means stacking a higher dose on a level that is still climbing, so the peak arrives later and higher than intended. For a compound with a week-long half-life, a four-week step is roughly five half-lives, which is not a coincidence.

The titration schedule calculator lays out a ramp week by week from a starting dose, target, step size and interval.

Where titration does not apply

Most research peptides have no titration schedule, because a schedule requires dose-finding data and dose-finding data requires trials. Where a ramp is circulated for a compound with no human trials behind it, the schedule is convention rather than evidence, and it is worth knowing which one you are reading.

This site labels that distinction on every compound page. A published titration schedule and a community protocol are different objects, and the difference is not presentation.

What happens when a step is not tolerated

A schedule assumes each step is tolerated before the next. When one is not, there are three ordinary responses and none of them is pushing through.

• Hold. Stay at the current dose for another interval rather than stepping up. This is the most common adjustment and it is explicitly anticipated in the labelling of several approved products.
• Step back down. Return to the last tolerated dose and hold there. If that dose is achieving the goal, it may simply be the dose.
• Stop. Some effects are reasons to discontinue rather than adjust, and that judgment belongs with the prescriber.

Extending a schedule is generally low risk. Compressing it is where problems come from, because the reason for the interval was adaptation and adaptation does not accelerate on request.

Titration is not a loading phase

The two get conflated and they are opposite in intent. A loading phase front-loads: a higher dose early to reach an effective concentration faster, then a lower maintenance dose. Titration does the reverse, starting below the target and climbing.

A compound can have both, and the distinction is what each is solving. A loading phase addresses time to effect, usually because the half-life is long enough that steady state would otherwise take weeks. Titration addresses tolerability. Reading a ramp as a loading phase, or the reverse, produces exactly the wrong adjustment when something goes wrong.

Related terms: half-life, steady state, loading phase, maintenance phase.