Last Updated: 11/07/2025

Wegovy Pens are an effective weight loss treatment from Novo Nordisk, the makers of Saxenda. Wegovy is considered an improvement on Saxenda, in terms of effectiveness, an improved dosing schedule and reduced side effects. Average body weight loss for Wegovy users is ~15% compared to just ~10% for Saxenda. Meanwhile, it requires just a once weekly injection, as opposed to a daily injection when using Saxenda.

What is Wegovy?

Wegovy is a type of medication known as a GLP-1 agonist. When you eat food, your body releases a hormone called GLP-1. This hormone slows down the passage of food from your stomach to your gut, which helps you to feel ‘full’. This can help you to avoid overeating. Wegovy activates the same receptors as GLP-1, meaning it has the same effect as this hormone. This means, if you use Wegovy, you will feel full after eating less food. When combined with a calorie-controlled diet and exercise, this can lead to weight loss.

How Effective is Wegovy?

Studies of Wegovy have shown that upwards of 80% of people who use Wegovy may lose up to 5% of their body weight over the course of 68 weeks. One study showed that people taking Wegovy had a mean change in body weight of 14.9% compared to 2.4% in the placebo group.

Wegovy effectiveness chart

Compared to Saxenda, Wegovy seems to be more effective – on Saxenda, only 63% of people lost that same 5% over the trial period. Whether this means Wegovy works for more people, or if it is more effective is still to be discovered. Either way, the numbers certainly seem to be in Wegovy’s favour when it comes to effectiveness.

Wegovy also has the edge in terms of dosage – where Saxenda requires daily injections, Wegovy is a weekly injection. This means the half-life of the drug (how long it takes to reduce in effectiveness) is much longer than Saxenda, meaning a single dose will go much further.

Please note that Wegovy works best when combined with a reduced calorie diet and exercise; Wegovy on its own may make you feel less full, and lead to eating less food, but this alone may only make you lose a small amount of weight.

Orlistat is another prescription weight loss medication. Compared to Wegovy, orlistat has the edge in terms of speed of action – in some cases, patients on orlistat have lost 5% of their body weight in as little as 12 weeks. However, longer term, the effectiveness drops. After 12 months on Orlistat, around 32% of patients had lost 5% of their body weight, compared to over 80% of patients on Wegovy after 16 months. This, combined with the possible side effects of orlistat, put Wegovy in the lead once more.

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Does Wegovy Have Any Side Effects?

As with all medications, some users will experience side effects when using Wegovy. These side effects may include;

  • Nausea
  • Vomiting
  • Diarrhoea
  • Abdominal pain

    • These side effects are normally mild, and should pass within a week or so as your body becomes used to the treatment. If they are particularly severe, or you experience any other side effects, speak to your doctor or pharmacist.

    We advise reading the Patient Information Leaflet for more advice and possible side effects of using Wegovy.

    Where Can I Get Wegovy?

    You can purchase Wegovy from our online Weight Loss clinic.

    We also currently supply Saxenda – a similar weight loss injection also made by Novo Nordisk – and Mounjaro, from Eli Lilly. Rather than a weekly dose, Saxenda is a daily injection, but Mounjaro is also weekly.

    Authorship

    Ian Coakley, Content Writer

    Authored by Ian Coakley

    Medical Content Writer

    Ian is a content writer at Simple Online Pharmacy. With a background in science communication, editing, and freelance writing, Ian aims to empower readers with accessible health information.