Guide
Dosage and Titration
How is the dose of weight loss medication increased over time?
Weight loss injections start at a low dose that is increased in stages, a process called titration. Tirzepatide begins at 2.5 mg once weekly for four weeks, moves to 5 mg, then rises in 2.5 mg increments no sooner than every four weeks, to a maximum of 15 mg. The starting dose is an adjustment dose, not a treatment dose. Increases happen only when the current dose is tolerated, and many people settle below the maximum.
Why doses start low
Starting at a therapeutic dose would produce gastrointestinal side effects severe enough that most people would stop treatment. Titration exists to let the body adapt to delayed gastric emptying gradually.
This is why the first weeks often produce little weight change. That is expected: at 2.5 mg the goal is tolerance, not effect. Judging the treatment by the first month is judging it before it has started.
The standard schedule
For tirzepatide the licensed schedule is set out below. Each step requires at least four weeks at the current dose, and a prescriber may extend that where side effects warrant it.
- 2.5 mg, weeks 1 to 4
- Adjustment dose. Not intended to produce weight change.
- 5 mg, from week 5
- The first therapeutic dose. Many people see appetite change here.
- +2.5 mg increments
- Increases no sooner than every four weeks: 7.5 mg, 10 mg, 12.5 mg.
- 15 mg maximum
- The licensed ceiling. Reaching it is not a target in itself.
The maximum dose is not the goal
A common misunderstanding is that treatment should escalate to 15 mg as a matter of course. It should not. The aim is the lowest dose that produces a satisfactory response and is comfortably tolerated.
Someone losing weight steadily at 7.5 mg with no troublesome side effects has no clinical reason to increase further. Escalating regardless adds side-effect burden without adding benefit.
Equally, a dose can be reduced. Where that is appropriate it is usually done gradually, stepping down by 2.5 mg at intervals rather than stopping abruptly.
Missed doses and timing
These treatments are taken once weekly, on the same day each week, with or without food. The day can be changed provided at least three days separate consecutive doses.
If a dose is missed, it can usually be taken within four days. Beyond that, the missed dose is skipped and the next taken on the regular day. Never take two doses to compensate.
One interaction is worth restating because it is easily missed: tirzepatide can reduce the effectiveness of oral contraceptives, most markedly after the first dose. A non-oral method, or an added barrier method, is advised for four weeks after starting and for four weeks after every dose increase.
Common questions
How long does it take to reach the maintenance dose?
Reaching 15 mg takes a minimum of 20 weeks, because each step requires at least four weeks at the previous dose. Many people stop at a lower maintenance dose. In the SURMOUNT-1 trial, participants reached their allocated maintenance dose at week 20.
What happens if I miss a dose?
If fewer than four days have passed, take it as soon as you remember and continue on your usual day. If more than four days have passed, skip it and take the next dose on schedule. Do not take two doses to make up for a missed one.
Can I increase my own dose?
No. Dose changes are prescribing decisions and require clinical review. Weight-management medicines are classed as high-risk, and a prescriber must assess tolerance and response before escalating. Self-directed increases raise the risk of severe gastrointestinal side effects.
Does a higher dose always mean more weight loss?
On average, higher doses produced greater weight reduction in trials, but the relationship is not guaranteed for an individual. Tolerability, adherence and dietary change all affect outcome. The clinical aim is the lowest effective dose, not the highest tolerated one.
What is the Mounjaro dosage schedule?
Treatment starts at 2.5 mg once weekly for four weeks, which is a tolerability step rather than a treatment dose, then increases in 2.5 mg steps no sooner than every four weeks. Maintenance is usually 5, 10 or 15 mg weekly, and the right one is the lowest that is working rather than the highest available. Your prescriber sets the schedule; refer to the patient information leaflet supplied with your pen for the definitive figures.
Sources
- Mounjaro, Summary of Product Characteristics · electronic medicines compendium
- Tirzepatide for managing overweight and obesity (TA1026) · NICE
- Tirzepatide prescribing guide for obesity · NHS Coventry & Warwickshire Formulary
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