Saxenda or Wegovy: which is better for weight loss?

What the trials show: semaglutide outperforms liraglutide by a meaningful margin

The STEP 1 trial, published in the New England Journal of Medicine, followed adults with obesity over 68 weeks on semaglutide 2.4mg. Average body-weight reduction was around 15%, compared with roughly 2.4% on placebo. Liraglutide 3mg (Saxenda) was tested in separate trials over 56 weeks and produced average losses closer to 5–8% in most analyses. These are not head-to-head numbers from the same study, so direct percentage comparisons carry caveats, but the gap is large enough that most clinicians treat it as directionally reliable.

The mechanism matters here. Both medicines are GLP-1 receptor agonists: they slow gastric emptying and reduce appetite via the same gut-hormone pathway. Semaglutide's longer half-life is why it works at once-weekly dosing; liraglutide clears the body faster, which is why Saxenda needs to be injected every day. From a pharmacology standpoint, semaglutide is simply a later, more refined molecule, and the weight-loss results reflect that.

Novo Nordisk has since taken the semaglutide dose further. The MHRA approved a higher 7.2mg Wegovy dose in 2026, with a dedicated single-dose pen confirmed in April of that year. Trials at 7.2mg reported around 20.7% average weight loss, narrowing the gap considerably with tirzepatide. If you want a fuller breakdown of how Wegovy compares with other injectable options, the Wegovy vs Ozempic page covers the semaglutide family in more detail.

How the UK licences compare, and what Saxenda's position looks like now

Both medicines are licensed in the UK for adults with a BMI of 30 or above, or 27 or above alongside at least one weight-related condition such as hypertension, high cholesterol or obstructive sleep apnoea. The NHS medicines page for semaglutide sets out the Wegovy indication clearly. Saxenda carries an equivalent licensed indication.

NICE recommended semaglutide for NHS use (TA875, March 2023), albeit within specialist weight management services and for a maximum of two years. Saxenda has no equivalent NICE technology appraisal recommending it for routine NHS weight-management use in England. In practice, Saxenda has been largely eclipsed (by Wegovy first, and now by tirzepatide (Mounjaro)) both in the evidence base and in clinical preference. That does not mean Saxenda is ineffective; some people have been stable on it for years and a prescriber may have good reasons to continue or start it. It does mean that for someone starting treatment today, it is rarely the first conversation.

For a side-by-side look at the two medicines across eligibility, dosing frequency and clinical outcomes, the full difference breakdown between Saxenda and Wegovy goes into more depth than this page can cover.

Daily injection versus once a week: the practical gap

Liraglutide's daily requirement is not a minor inconvenience for everyone. Adherence data across GLP-1 trials consistently shows that more frequent dosing correlates with higher discontinuation rates over time. Keeping a Saxenda pen in the fridge door and pulling it out every morning (including weekends, holidays and days when nausea is already a problem) is a real commitment. Wegovy's weekly schedule means most people pick a consistent day that fits their life and stick to it.

Side-effect profiles overlap substantially: nausea, vomiting, constipation and indigestion are common to both, tend to be most noticeable at the start or after a dose increase, and typically settle within days to a couple of weeks. Neither medicine should be used during pregnancy or breastfeeding, and neither is licensed for anyone under 18. Women on oral contraceptives starting tirzepatide (not semaglutide) should add a barrier method for the first four weeks and after each dose increase, because tirzepatide can reduce pill absorption, that distinction is worth knowing if you are comparing all three GLP-1 options to work out which is better suited to you.

If side effects or dose questions come up during treatment at nume, our prescribers are available for aftercare seven days a week. You can also find general aftercare information on our FAQs page.

What is available through a regulated UK pharmacy, and what is not

Saxenda is not dispensed by nume. Our weight-loss treatments are Wegovy (semaglutide injection and, since MHRA approval in June 2026, the Wegovy tablet) and Mounjaro (tirzepatide). If you are weighing up your options, the Wegovy treatment page covers what a consultation involves, how the process works and what is included in the price. For a broader look at the options we offer, our weight-loss treatments overview is a useful starting point.

Private pricing for any GLP-1 medicine is worth understanding before you start. Since Eli Lilly raised Mounjaro's UK list price in September 2025, typical private costs for these medicines range roughly £149–£375 per month depending on the drug, dose and provider, and what those headline prices include varies considerably. If you are still working through whether Wegovy is better than Saxenda for weight loss given your personal circumstances, our Wegovy price comparison guide breaks down what to look for when reading a provider's quoted figure alongside the clinical picture, and the Wegovy price comparison guide breaks down what to look for when reading a provider's quoted figure.

Every consultation at nume is reviewed by a GPhC-registered Independent Prescriber. A real clinician reads your answers the same day, the medicine, the dose and the suitability question are theirs to determine, not a form's. If you would like to find out whether Wegovy or Mounjaro is the right fit for your circumstances, speak to our prescribers through a free consultation.