Encyclopedia entry · Editorial commentary

GLP-1 starting dose

Every licensed UK GLP-1 starts at a low introductory dose and titrates upward at monthly intervals to the maintenance dose set in the SmPC. The ladder is published in the SmPC on emc.medicines.org.uk and applied by your prescriber to your individual clinical picture. PeptideClear does not reproduce dose schedules.

Why a starting-dose phase exists at all

The gastrointestinal effects characteristic of this class (delayed gastric emptying, reduced appetite signalling) are dose-dependent. Beginning at a low introductory step gives the gastrointestinal system time to adapt and reduces the incidence of nausea and vomiting that would typically follow a jump straight to a maintenance dose. This is why every UK-licensed GLP-1 weight-management product carries a built-in titration phase rather than a single starting strength.

The specific introductory step, the intervals between increases and the maintenance dose for each medication are set in the SmPC, the document the MHRA approves for each marketing authorisation. The SmPC is the authoritative source. PeptideClear does not reproduce the milligram values from the SmPC because that crosses from editorial commentary into the territory of advertising or summarising a prescription-only medicine to the public, which UK rules reserve for the manufacturer and the prescriber.

Where the published schedule lives

The SmPC for each UK-licensed GLP-1 is published on the MHRA Products database and on emc.medicines.org.uk. The dosing section sets out the introductory step, the interval before the next increase, the conditions under which a step can be held or extended, and the maintenance dose. The accompanying Patient Information Leaflet, supplied in the medication box, restates the same schedule in plain language for the patient. Both documents are kept current by the marketing-authorisation holder under MHRA oversight.

Your prescriber applies that published schedule to your individual circumstances. Where the SmPC permits extended titration, the prescriber may hold a step for an additional period if tolerability is poor. Where the SmPC permits, the prescriber may also decide that a sub-maximal step is the right maintenance dose for you, rather than the highest licensed strength.

Why titration is non-negotiable

Starting at a maintenance dose typically causes severe nausea, vomiting and intolerance, and is the most common reason for treatment dropout reported in the literature. Every UK SmPC instructs the prescriber and the dispensing pharmacist not to issue a step above the patient's current titration position. The titration phase is therefore both a clinical safety mechanism and a regulatory one: the medication is licensed on the basis that it will be introduced in this stepped way.

Editorial reporting routinely conflates the maximum licensed dose with the dose any individual will reach. In practice the published evidence and UK clinical observation both describe a wide spread: some patients settle at an early step, others progress to a higher one, and the right maintenance dose is whichever step delivers tolerable side effects and adequate clinical effect for that person.

What happens if the patient does not tolerate the next step

The prescriber pauses titration. Options described in the SmPC include holding at the current step for an extended period before re-trying the next increase, holding at the current step as the long-term maintenance, or stepping back if symptoms emerged immediately after a dose increase. The SmPC for each medication explicitly allows extended titration where needed and does not require reaching the maximum dose for a course to be considered complete or effective.

These are clinical judgments made by your prescriber, not adjustments a patient should make independently. The dose stamped on the pen the pharmacy dispenses is the dose your prescriber has authorised for the current period; using a different dose without a new prescription falls outside the licensed use.

How NHS phasing interacts with titration

On the NHS pathway under NICE TA1026, eligibility is reviewed at the specialist weight-management service and tirzepatide is then introduced by the prescribing team according to the SmPC. The NHS pathway includes a continuation rule that looks for a defined weight-loss outcome by a defined review point; failure to meet it triggers reassessment rather than open-ended supply. The clinical detail of how titration is run in each ICB cohort is set by the local service rather than by a national template.

On the private route, a GPhC-registered online pharmacy or a CQC-regulated clinic applies the same SmPC schedule. The difference is administrative rather than pharmacological: the medication, the SmPC and the titration steps are the same.

Where to ask

• · The SmPC and Patient Information Leaflet for your specific medication on emc.medicines.org.uk and the MHRA Products database.
• · Your prescriber: NHS specialist weight-management service, private clinic prescriber, or pharmacist prescriber. Your prescriber decides the dose schedule that fits your file.
• · Your dispensing pharmacist for questions about administration and storage.
• · NHS 111 if you cannot reach your prescriber and are unsure what to do.
• · Suspected side effects can be reported through the MHRA Yellow Card scheme.

Related: PIL · pen vs vial · NICE TA1026 explained.