Switching from Liraglutide to Semaglutide: What the Dose Conversion Actually Means

Why can't you simply convert the milligram figures from liraglutide to semaglutide?

Liraglutide's maximum licensed dose for weight loss is 3.0 mg daily, while semaglutide's standard weekly maintenance dose (Wegovy) is 2.4 mg, and a higher 7.2 mg dose received MHRA approval in April 2026. Looking at those numbers and assuming a proportional relationship would be misleading. Potency is not measured in milligrams across different molecules; it depends on how strongly a medicine binds to its receptor, how long it remains active in the body, and how the body processes it over time.

Semaglutide has a much longer half-life than liraglutide, roughly one week compared with roughly thirteen hours. That is exactly why one weekly injection of semaglutide can sustain a clinical effect that daily liraglutide achieves through repeated doses. The pharmacokinetics are fundamentally different, so a conversion table of the kind that exists for some pain medicines or anticoagulants simply does not apply here. A question our prescribers hear most weeks is whether the patient can work out their semaglutide starting dose based on where they finished with liraglutide. The honest answer is that the starting dose is the same for everyone: the titration schedule begins at the lowest rung regardless of prior treatment history.

The semaglutide dosing schedule for Wegovy runs from 0.25 mg up through 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg, with each step separated by roughly four weeks. The prescriber follows that pathway and adjusts based on tolerability, not on the liraglutide dose you were taking previously. This protects you from GI side effects that are well-documented when semaglutide is escalated too quickly.

Does stopping liraglutide require a washout period before starting semaglutide?

There is no fixed regulatory washout period specified in the UK Wegovy SmPC for patients switching from liraglutide, but prescribers do not generally recommend overlapping two GLP-1 medicines. The standard practice is to stop liraglutide and begin the semaglutide titration promptly, rather than waiting weeks, because the therapeutic effect on appetite is not cumulative across different agents and the additive GI burden of two GLP-1 medicines simultaneously would be significant.

What matters more than timing is the reason for the switch. If liraglutide was stopped because of side effects, a prescriber will want to understand which ones before initiating semaglutide, since the two medicines share a broadly similar GI side-effect profile, nausea, vomiting, diarrhoea, constipation, and reflux are common to both, particularly during dose escalation. If the switch is driven by insufficient weight loss on liraglutide, the prescriber will note that clinical trials support greater average reduction with semaglutide, and the evidence on semaglutide's weight-loss outcomes is part of that clinical conversation.

NHS guidance, including the NHS patient information on semaglutide, and the relevant prescribing information both emphasise that treatment decisions belong with the clinician. Self-managing a switch carries real risk, and this is one situation where that caution is well-founded.

What is actually licensed for weight loss in the UK now, and where does liraglutide fit?

Liraglutide (Saxenda, 3.0 mg daily injection) is licensed in the UK for weight management in adults with a BMI of 30 or above, or 27 or above alongside a weight-related condition. It remains a legitimate licensed option. Saxenda is not, however, a medicine that nume dispenses. Our pharmacy focuses on the two GLP-1 weight-loss medicines for which we have clinical pathways and supply: Wegovy (semaglutide injection, including the newer 7.2 mg pen) and Mounjaro (tirzepatide), the dual GIP and GLP-1 receptor agonist.

If you are currently taking liraglutide through another provider and are thinking about switching, the Wegovy dose pathway is the most directly comparable injectable GLP-1 route. Mounjaro works on two receptors rather than one and produced greater average weight reduction in the SURMOUNT-5 head-to-head trial against semaglutide 2.4 mg, published in the New England Journal of Medicine in 2025, though which medicine suits a particular person is always a clinical decision. For a broader look at what licensed weight-loss treatments are available privately, our treatment overview sets out the options clearly.

It is worth noting that Ozempic, another semaglutide product, is licensed in the UK for type 2 diabetes rather than weight loss; the distinction between Wegovy and Ozempic dose contexts matters if you encounter those two names together. Similarly, Rybelsus tablets are oral semaglutide for diabetes, not weight management. The weight-loss tablet form of semaglutide is Wegovy tablets, approved by the MHRA in June 2026, with a separate dosing schedule, though that is a different product from the injectable and the liraglutide comparison is with the injection.

What should you actually do if you want to switch from liraglutide to semaglutide?

Talk to a prescriber before stopping or starting anything. That sounds obvious, but the practical steps matter. Your prescriber needs to know your current liraglutide dose, how long you have been on it, your weight trajectory, any side effects you experienced, and your medical history including any conditions that affect which GLP-1 medicine is appropriate. They will confirm whether semaglutide is clinically suitable for you and, if so, initiate the titration schedule at the correct starting point.

If you came to liraglutide through a private provider and are now considering semaglutide, you can approach a new provider with your treatment history, including evidence of your current dose and any clinical notes. Transfer patients at nume go through the same clinical review as new patients; prescribers check your records before approving any treatment. You can explore the commonly asked questions about switching treatments or review what the private cost of Wegovy looks like before deciding whether to proceed. When you are ready, the right step is a consultation with a prescriber who can assess whether semaglutide is the right next move for you specifically. Speak to our prescribers through our free consultation.