FAQ · GLP-1 · Editorial commentary

GLP-1 FAQ

UK editorial commentary on the questions readers most often ask about Mounjaro, Wegovy and GLP-1 medications generally. Each answer signposts the authoritative source. The SmPC sets the titration; the PIL lists side effects; your UK-licensed prescriber decides individual dosing; NHS 111 and 999 are the safety net; report concerns through the MHRA Yellow Card scheme.

What is the difference between Mounjaro and Wegovy?

Mounjaro is the UK brand under which tirzepatide is licensed by Eli Lilly. Wegovy is the UK brand under which semaglutide is licensed by Novo Nordisk for weight management. They are different molecules with different mechanisms described in the literature (tirzepatide is a dual GIP and GLP-1 receptor agonist; semaglutide is a GLP-1 receptor agonist). PeptideClear does not publish comparative efficacy figures for prescription-only medicines and does not recommend one over the other. The decision between them is a clinical judgment made by a UK-licensed prescriber on the basis of the SmPC, your clinical picture and the relevant NICE technology appraisal.

How do I get Mounjaro on the NHS?

NHS England Cohort 1 (BMI 40 or above, with four or more weight-related comorbidities) has been live since June 2025. Cohort 2 launches 23 June 2026 (BMI 35 to 39.9, four or more comorbidities). Beyond June 2026, NHS England extends eligibility progressively in later phases, prioritised by clinical need, over a period of up to 12 years; criteria for the post-June 2026 cohorts have not yet been finalised. Scotland, Wales and Northern Ireland each operate their own timetable under their own appraisals. Eligibility decisions are made by the specialist weight-management service, not on this page.

How much does Mounjaro cost privately in the UK?

GLP-1 medication is dispensed through NHS specialist weight-management services, UK private clinics, and UK-licensed online pharmacies. Published pricing is the responsibility of each route and changes; PeptideClear does not reproduce per-route POM prices. For an editorial overview of how costs are structured across routes, see our cost and supply guide, which explains what drives the figures rather than quoting them.

I missed a dose of Mounjaro, what should I do?

The instruction for what to do if a dose is missed is set out in the MHRA-approved Patient Information Leaflet supplied in the medication box and on emc.medicines.org.uk. PeptideClear does not reproduce the specific time window or actions, because the right answer depends on factors a general website cannot know: which dose you are on, where you are in titration, how long ago your last dose was, and what your prescriber has told you to do. Read the PIL supplied with your medication and contact your prescriber, your pharmacist, or NHS 111 if you are unsure.

What are the side effects of Mounjaro?

The full list of side effects, with frequency categories, is in the MHRA-approved Patient Information Leaflet supplied with the medication and in the SmPC on emc.medicines.org.uk. PeptideClear does not reproduce the triage detail because the right action for any specific symptom depends on the individual case. The published references describe gastrointestinal effects as most commonly reported during titration. For severe or persistent symptoms contact your prescriber or NHS 111; in an emergency call 999. Suspected side effects can be reported through the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk.

Will I regain the weight after stopping Mounjaro?

The published literature describes substantial weight regain on average in the months after stopping GLP-1 weight-management medication, with wide individual variation. Aftercare planning, resistance training and protein intake are commonly discussed in the literature as behavioural levers that influence the regain trajectory. The decision about how and when to stop is a clinical one made between you and your prescriber, who will refer to the SmPC and the current NICE appraisal.

Can I take Mounjaro during pregnancy?

Both Mounjaro and Wegovy are contraindicated in pregnancy on their UK SmPCs. UK prescribing guidance advises stopping GLP-1 medication well in advance of trying to conceive; the specific interval is set out in the SmPC for each medication. If you become pregnant unexpectedly while taking a GLP-1, contact your prescriber the same day.

Can I switch from Wegovy to Mounjaro?

Switching between prescription-only weight-management medications is a clinical decision made by your UK-licensed prescriber, not a self-directed change. The relevant SmPCs and the prescriber's view of your titration history, tolerability and clinical picture determine the appropriate approach. PeptideClear does not publish switching protocols.

Is Mounjaro better than Wegovy for me?

PeptideClear does not publish POM efficacy comparisons or recommend one prescription-only medicine over another for any individual. The two medicines have different mechanisms described in their SmPCs, different NICE technology appraisals (TA1026 for tirzepatide, TA875 for semaglutide), and different labelled indications. Which is appropriate for you, and at what dose, is a decision between you and a UK-licensed prescriber, who will refer to the SmPCs, your clinical history and the relevant NICE appraisal.

Does Mounjaro affect contraception?

The Patient Information Leaflet for Mounjaro covers interactions with oral hormonal contraceptives, including the recommendation around barrier methods or non-oral routes during titration. The PIL is the authoritative source for the specific timing and the conditions. If you are using oral contraception, discuss the PIL guidance with your prescriber or your usual contraception provider.

Does rapid weight loss affect facial appearance?

Rapid or substantial weight loss from any cause reduces facial fat alongside body fat; the published literature on bariatric surgery and very-low-calorie diets describes the same effect. Pace of loss, resistance training and adequate protein are commonly raised by clinicians in this context. This is general editorial commentary and not a recommendation for any specific intervention.

Is Mounjaro on the WADA list?

Tirzepatide and semaglutide are both included on the WADA prohibited list as peptide hormones. Tested athletes who are prescribed a GLP-1 for a licensed indication need to follow the WADA Therapeutic Use Exemption process; the current list and the TUE procedure are on the WADA website.

In-depth GLP-1 articles

Each short answer above links to a full editorial article where we cover the topic in detail, including the relevant regulatory references and clinical guidance context.