The key difference: semaglutide vs liraglutide

You inject Saxenda daily. It works. You barely think about it now. So why change? 

Most of how Wegovy pills compare to Saxenda comes down to the active ingredient.

Both Wegovy and Saxenda are glucagon-like peptide-1 (GLP-1) receptor agonists, sometimes called GLP-1 agonists for short. This class of weight loss treatments works by mimicking a gut hormone released after eating. Less hunger. Slower stomach emptying.

Saxenda uses liraglutide. Wegovy uses semaglutide. In practice, the main difference is staying power. Semaglutide grips the GLP-1 receptor harder and stays in your system for about a week. Liraglutide, on the other hand, is removed in roughly 13 hours.

Your body absorbs less semaglutide from a tablet, which is why the pill dose is so much higher: 25mg daily compared with Saxenda’s 3mg.

Efficacy: what the evidence shows

Saxenda first. In the SCALE trial, over 3500 adults with a body mass index (BMI) of 30 or above had a daily injection for 56 weeks. Average weight loss with diet and exercise: about 8%.

Now the Wegovy pill. OASIS 4 followed 307 adults with overweight or obesity for 64 weeks. Average weight loss: 13.6%. Starting at 95kg, that is around 13kg body weight gone, roughly double the weight loss seen with Saxenda in trials. The Wegovy pills weight loss results from OASIS 4 are the strongest oral data for this drug class.

One head-on comparison between the two drugs exists. In PIONEER 4, oral semaglutide beat liraglutide on weight loss. But the patients had type 2 diabetes and took lower doses aimed at blood sugar levels rather than body fat. It is the closest direct look at semaglutide vs liraglutide weight loss, but it was not designed for this condition. 

Saxenda has been around longer, so prescribers know more about how people get on with it outside trials. No one knows yet whether Saxenda vs oral semaglutide will show the same gap once real patients are using it day to day.

Administration: daily injection vs daily pill

Both require daily use. Saxenda is a daily injection under the skin, usually the abdomen, thigh, or upper arm.

The Wegovy pill is swallowed first thing on a completely empty stomach with no more than 120ml of water. Then nothing. No food, no tea, no other tablets for at least 30 minutes.

The needle goes away. But if your morning already involves other medicines, that fasting window gets complicated. Whether you choose the Wegovy pill or Wegovy vs Saxenda injections may come down to which routine you can stick with.

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Side effects

Potential side effects are similar across both drugs. Nausea, vomiting and diarrhoea came up most in both trials, mostly mild and worst during the early weeks while the dose was going up.

In SCALE, 6.4% of people stopped taking Saxenda because their gut could not handle it. In OASIS 4, 3.2% stopped the Wegovy pill.

Eating smaller meals, avoiding fatty food, and staying hydrated can help manage gut symptoms during the early weeks.

Saxenda can also cause injection site redness or irritation, which does not apply to the pill.

Saxenda has been prescribed since 2015 as a safe and effective weight loss treatment. The Wegovy pill’s side effects are consistent with those of other GLP-1 agonists, but long-term real-world data does not exist yet.

Switching from Saxenda to Wegovy pill

You go back to the beginning. If you switch from Saxenda to the Wegovy pill, you start at 1.5mg regardless of your previous dose and build up to 25mg over 12 weeks.

Gut side effects like nausea may come back while your body adjusts. That can happen even if Saxenda never affected you.

Talk to us before making any changes. Already on the Wegovy injection and considering switching between Wegovy formats? This follows a different process.

Why is Saxenda being superseded?

In trials, semaglutide produces roughly double the weight loss of liraglutide. UK guidelines now reflect that. 

The Wegovy pill has US approval, but the Medicines and Healthcare products Regulatory Agency (MHRA) has not cleared it in the UK yet. For the latest on Wegovy pills vs Saxenda UK availability, speak to us.

Roughly 1 in 2 people prescribed GLP-1s for weight loss stop within a year. If Saxenda is doing its job, hold on to that.

When should I see a doctor?

If nausea, vomiting, diarrhoea, or constipation have not settled, get in touch. We can carry out a medical review and adjust your dose.

Contact your GP, pharmacist or another healthcare professional, or ring NHS 111 if:

  • You experience sudden, sharp or burning upper stomach pain that moves to your back or worsens after eating. Pancreatitis (swelling of the pancreas) is a rare known risk with GLP-1 medicines.
  • Your skin or the whites of your eyes go yellow. Rapid weight loss can trigger gallstones, and gallbladder problems have come up with GLP-1 drugs before.
  • Persistent nausea (feeling sick), with or without vomiting, or diarrhoea persists beyond a few days. Dehydration can follow, and it hits harder if you are older or on water tablets (diuretics).
  • Your eyesight changes, particularly if you have type 2 diabetes.
  • You have thoughts of self-harm or suicide. Rare, but reported. Take it seriously.
  • Something feels wrong, and you cannot pin it down. Trust that.

Dial 999 if:

  • Your face, lips, tongue, or throat swell up, you struggle to breathe, or your heart races. Severe allergic reaction.
  • Stomach pain is intense and will not shift.
  • Anything feels life-threatening. Do not wait.

Frequently asked questions

Wegovy pills vs Saxenda UK: which should I choose?

You cannot choose the Wegovy pill yet. It is not approved in the UK. When it arrives, we can help you decide based on your routine and how you handle side effects.

Wegovy pill vs Saxenda, which is better?

Depends what matters to you. Saxenda working well, injections not a problem, and weight coming off? You may not need to change anything. A fasting window every morning is not easier than a daily injection for everyone.

Is the Wegovy pill better than Saxenda?

By the numbers, yes. Semaglutide beats liraglutide on weight loss in every trial run so far. But whether that applies to you is a different question. Can you manage the pill routine? How does your body handle a new medication? Will you stay on it? We can help.

Key takeaways

  • Saxenda and Wegovy both target the same appetite pathway. The difference: semaglutide stays active longer. It also produces more weight loss.
  • The numbers speak for themselves. Wegovy pill: 13.6% average weight loss over 64 weeks. Saxenda: around 8%.
  • Swapping a daily injection for a pill sounds appealing, but that strict morning fasting requirement will not suit everyone.
  • Gut symptoms caused fewer people to quit the Wegovy pill than Saxenda (3.2% vs 6.4%).
  • Thinking about switching from Saxenda? You start from scratch. Lowest dose, 12-week build-up. Speak to us first.

References

WEGOVY (semaglutide) Tablets Prescribing Label, NDA 218316, U.S. Food and Drug Administration [Accessed 1 April 2026].

Oral Semaglutide at a Dose of 25 mg in Adults with Overweight or Obesity, New England Journal of Medicine, [Accessed 1 April 2026].

A Randomized, Controlled Trial of 3.0 mg of Liraglutide in Weight Management, New England Journal of Medicine, [Accessed 1 April 2026].

Oral semaglutide versus subcutaneous liraglutide and placebo in type 2 diabetes (PIONEER 4), The Lancet, 2019;394(10192):39-50 [Accessed 1 April 2026].

Switching Between Glucagon-Like Peptide-1 Receptor Agonists: Rationale and Practical Guidance, Clinical Diabetes, 2020;38(4):390-402 [Accessed 1 April 2026].

Semaglutide for managing overweight and obesity (TA875), National Institute for Health and Care Excellence, 2023 [Accessed 1 April 2026].

Gastrointestinal Tolerability of Once-Weekly Semaglutide 2.4 mg in Adults with Overweight or Obesity, Diabetes, Obesity and Metabolism [Accessed 1 April 2026].

Discontinuation and Reinitiation of Dual-Labeled GLP-1 Receptor Agonists Among US Adults With Overweight or Obesity, JAMA Network Open [Accessed 1 April 2026].

Authorship

Shereen Amin, Pharmacist Independent Prescriber & Freelance Medical Writer

Authored by Shereen Amin

Pharmacist Independent Prescriber & Medical Writer
GPhC: 2073003

Shereen is a Pharmacist Independent Prescriber and medical writer with over ten years' experience across NHS primary care, digital health and specialist services. She writes evidence-based health content for Simple Online Pharmacy, turning complex clinical information into guidance patients can actually use.

Arslan Kaleem, Pharmacist

Medically Reviewed by Arslan Kaleem

Pharmacist
GPhC: 2225919
With a strong background in clinical pharmacy, Arslan Kaleem has a particular interest in training, auditing, and streamlining clinical processes to improve patient safety and efficiency. As a pharmacist at Simple Online Pharmacy, he is involved in training pharmacists, reviewing clinical content, and upholding high standards of care.