Switching GLP-1 medications is common, and rarely as dramatic as it sounds. Most people who move — from Wegovy to Mounjaro, the other way, or onto the newer Wegovy pill — do it for one of a handful of practical reasons, and the mechanics follow the same pattern each time. This guide walks the decision in order: when a switch is worth it, how the dose ladder restarts, what it costs, and who signs it off.
Switching GLP-1 means starting a fresh dose ladder on the new medicine — not carrying your old dose across. A UK prescriber decides whether to switch and where to begin, you pay the lower starter-dose price again for a few weeks, then climb back to a maintenance dose. Plan for both the restart and the cost.
When switching GLP-1 actually makes sense
There are only a few honest reasons to change medicine. Work through them in order — if none apply, staying put is usually the right answer.
- You want more weight loss. This is the most common trigger for moving from Wegovy to Mounjaro. In the trials, tirzepatide (Mounjaro) reached around 20–22% average weight loss at higher doses, ahead of semaglutide (Wegovy) at roughly 15%. A head-to-head study also favoured Mounjaro. If you have plateaued on Wegovy at a full dose, this is a real, evidence-based reason to ask about switching.
- Side effects you cannot settle. Nausea, reflux or fatigue that will not calm down even after weeks at a steady dose can be a reason to try the other molecule, which some people tolerate better.
- Needles are the problem. If the weekly injection itself is the sticking point, the daily Wegovy pill (oral semaglutide) is the needle-free route where a provider stocks it.
- Track record or heart-health evidence. Some people move to Wegovy specifically because it has the longest UK history and is the option shown to reduce cardiovascular events in people with existing heart disease.
- Cost. A legitimate reason on its own — but switch medicine for the right clinical reason first, then find the cheapest regulated provider for whichever medicine you land on.
Not sure a switch is even the right move? Our which GLP-1 is right for me guide and the five-question decision guide both help you sanity-check the choice before you change anything.
How the dose ladder restarts when you switch
This is the part people most often get wrong. Mounjaro and Wegovy are different molecules on different dose scales, so you cannot simply match milligram for milligram. A prescriber will almost always place you at or near the bottom of the new medicine's ladder and step you up again gradually.
Both medicines are designed to be titrated — started low and increased slowly to keep side effects manageable:
- Mounjaro starts at 2.5 mg weekly for 4 weeks (a starter dose, not a treatment dose), then 5 mg, then rises in 2.5 mg steps up to a maximum of 15 mg.
- Wegovy starts at 0.25 mg weekly, then climbs through 0.5, 1, 1.7 and up to 2.4 mg.
- The Wegovy pill follows its own ladder, starting at 1.5 mg.
Because the new medicine clears the old one's ladder entirely, expect to spend a few weeks back at low doses before reaching a maintenance level. That is not a setback — it is how you avoid a rough run of nausea. Both pens are weekly injections that leave the body slowly, so a short, prescriber-set changeover between the last old dose and the first new one is normal. Do not improvise the timing.
The Weight Clinic is our recommended provider for exactly this kind of change: monthly video reviews so a clinician actually sees how the new medicine is landing, and a refund if you are declined. New patients get £35 off the first order with code NEWME.
Visit The Weight Clinic →What switching costs: the starter-dose reset
Switching resets your bill as well as your ladder. Whichever medicine you move to, you pay its lower starting-dose price for the first few weeks, then step up toward the ongoing price. That makes the starter months cheaper — a small silver lining to restarting — but it is worth knowing the numbers before you commit.
The table below shows the starter-dose entry point for each medicine at our recommended provider, The Weight Clinic, alongside the wider UK market range at the same starter dose. Prices last checked 4 July 2026.
| Medicine (starter dose) | The Weight Clinic — first month | The Weight Clinic — ongoing | UK market range, same starter dose |
|---|---|---|---|
| Mounjaro 2.5 mg ★ Recommended providertirzepatide · most weight loss | £125with code NEWME | £160 | £145.99 – £229 |
| Wegovy 0.25 mgsemaglutide · longest track record | £80with code NEWME | £115 | £79.97 – £164 |
| Wegovy pill 1.5 mgoral semaglutide · needle-free | £80with code NEWME | £115 | £99 – £115 (limited stock) |
Two things stand out. The starter months are genuinely cheaper than maintenance — useful if you want a lower-cost trial period while a prescriber watches how you settle. And the same starter dose spans a wide range across UK pharmacies: Mounjaro 2.5 mg alone ran from £145.99 to £229 when we last checked, an £83 gap for the identical licensed medicine. Once you know your target medicine, the full price comparison on our homepage finds the cheapest regulated option at every dose on the ladder.
A simple decision path for switching
If you are weighing a switch, run it through these steps in order rather than acting on a single frustration.
- Name the real reason. More weight loss, unmanageable side effects, avoiding needles, wanting the heart-health evidence, or cost. If you cannot name one clearly, a switch is probably premature — give your current dose more time first.
- Check you are at a fair test. Switching for “not enough weight loss” only makes sense once you have reached a full maintenance dose and given it time. Bailing at a starter dose tells you little.
- Pick the target medicine. Chasing results points to Mounjaro; tolerance or track record can point to Wegovy; needle avoidance points to the pill. Our Mounjaro or Wegovy for beginners guide breaks down the trade-offs.
- Complete a fresh consultation. A switch is a new clinical decision. Expect the usual questions about weight history, health conditions and current medicines. The prescriber decides whether to switch and where on the new ladder to start you.
- Then pick the cheapest regulated provider. Medicine first, provider second. Compare ongoing prices for your new medicine — you will pay the ongoing figure for most of the year, not the promo.
Never change medicine, dose or timing yourself, and never buy from unregulated sellers or “compounded” copies to bridge a switch — that is genuinely dangerous. A UK prescriber must review and approve every switch. Report any suspected side effect through the MHRA Yellow Card scheme.
Who decides — and what that protects
Every switch runs through a UK prescriber. They review your consultation, judge whether the change is appropriate, set the starting dose, and decide the changeover timing. Approval is never guaranteed — a clinician can decline, and an honest provider will not pretend otherwise. That gatekeeping is the point: it stops a switch turning into a rough month of side effects or an unsuitable medicine. It is also why the provider you switch with matters as much as the medicine — regular follow-up means someone is watching how the new medicine lands in those first weeks back on the ladder, the window when tolerance problems show up. That is a big part of why The Weight Clinic is our recommended pick.
The Weight Clinic runs a free online consultation, gives you monthly video reviews with a clinician throughout the new dose ladder, and refunds you if a prescriber declines. New patients save £35 on the first order with code NEWME. Prices last checked 4 July 2026 — confirm the current figure on their site.
Visit The Weight Clinic →Frequently asked questions
Do I have to restart at the lowest dose when I switch GLP-1?
Usually yes. Because Mounjaro and Wegovy are different molecules with different dose ladders, a UK prescriber will almost always start you at or near the bottom of the new medicine's ladder and step you up again, rather than matching your old dose milligram for milligram. That protects you from a rough run of side effects. The exact starting point is the prescriber's call, based on your history.
Can I switch from Mounjaro to Wegovy or the other way round?
Yes, both directions happen. People move from Wegovy to Mounjaro chasing more weight loss, and from Mounjaro to Wegovy for tolerance, cost or its heart-disease evidence. A prescriber reviews your consultation each time and decides whether the switch is appropriate and where on the new ladder to begin.
Is there a gap between stopping one medicine and starting the next?
Both medicines are weekly injections that clear slowly, so a short changeover is normal. A common approach is to start the new weekly dose about a week after the last dose of the old one, but the timing is a clinical decision your prescriber sets for you, not something to improvise.
Will I have to pay the starter-dose price again after switching?
Yes. Switching means a fresh ladder, so you pay the new medicine's lower starting-dose prices for the first few weeks before climbing back to a maintenance dose. At The Weight Clinic, for example, a Wegovy starter month is £80 with code NEWME and a Mounjaro starter month is £125 with the same code, versus higher ongoing prices later.
Can I switch to the Wegovy pill instead of an injection?
Where a provider stocks it, oral semaglutide is a needle-free route and some people move to it to avoid injections. It follows its own dose ladder starting at 1.5 mg. Availability is more limited than the pens, and as with any switch a UK prescriber decides whether it suits you. If BMI is your question rather than switching, our BMI 27–30 options guide covers eligibility.
Once you know which medicine you are switching to, compare every regulated UK provider at your dose on the GLP Finder price table, or start a fresh consultation with our recommended provider, The Weight Clinic.