Confused by Wegovy switching claims? Here’s what the evidence really says

With fast‑moving (and sometimes conflicting) claims about Wegovy, it can be hard to know what to trust when you’re considering a switch. A lot of the confusion comes from mixing up doses, brands, timelines, and UK‑specific rules.

Below are some of the claims we’ve seen - paired with what the evidence actually says - so you can make informed decisions about your health.

What’s being said - and what the data shows

“Wegovy leads to 20%+ weight loss.”

What the evidence shows:

On the UK-licensed dosing schedule (up to 2.4 mg weekly), average weight loss in large, year‑long trials was 17.5%.¹ 

Recent headlines about 20% weight loss are based on higher doses (7.2 mg) reported in clinical trial data released by the manufacturer.² Those doses are not licensed or available. It isn’t accurate to promise 20% average loss on the approved 2.4 mg dose, or any dose you’ll receive currently in the UK. 

“Wegovy is more effective than Ozempic.”

What the evidence shows:

Comparing Wegovy and Ozempic for weight loss is misleading: both contain semaglutide and would be expected to have similar effects at the same dose. However, in the UK, Ozempic is only licensed for type 2 diabetes at a lower dose than Wegovy is licensed for weight loss.

“Ozempic is available for weight loss in the UK.”

What the evidence shows:

Wegovy is the only licensed brand of semaglutide for weight loss in the UK. Ozempic, however, is licensed for type 2 diabetes only and not for weight management. If you see a provider offer Ozempic or compare the results against Wegovy favourably, it’s best to avoid. Prescribing should follow UK licences and guidance.

“A nationwide shortage of medication has led to a price increase for Mounjaro.”

What the evidence shows:

There isn’t a confirmed national stock shortage right now. Demand is high, so some pharmacies may have intermittent gaps, but there’s no need to panic-buy or stockpile - this isn’t clinically approved and can disrupt access for others. If anything changes regarding our stock availability, we’ll be the first to let you know.

“Weight loss programmes are effective without lifestyle support.”

What the evidence shows:

The Wegovy licence requires a reduced‑calorie diet and increased physical activity - every trial combined semaglutide with lifestyle interventions. The most recent study included monthly counselling by qualified healthcare professionals, either in person or by telephone.¹

Prescribing or using the medicine without lifestyle support misrepresents the evidence and will lead to smaller, more short-term results. 

Making sense of the headlines

Before you believe a headline or ad, check:

• Dose: Is the result for Wegovy from a UK-licensed dose (0.25mg - 2.4mg weekly), or a higher dose?

• Duration: Is the figure from 68 weeks, or a short‑term snapshot?

• Study size and design: Large, long, randomised controlled trials are more reliable than small, uncontrolled reports.

• “Up to” language: “Up to 20%” often describes a subset, not the average person.

What to do before you switch 

• Choose a regulated provider: Look for a UK‑registered prescriber and pharmacy, clear inclusion of follow‑ups, side effect management, secure delivery, and transparent pricing.

• Speak to a clinician: Confirm suitability, medical history, expectations, and a personalised plan.

• Expect support beyond the pen: Find a programme that provides advice on nutrition, activity and habit‑change coaching aligned to the licence and the evidence.

The numan take

It’s normal to feel unsure when headlines and the facts don’t match. Focus on UK‑licensed doses, long‑term data, and lifestyle‑backed programmes. That’s how you stay safe and set up for lasting results.

References

1. Rubino, D., Abrahamsson, N., Davies, M., et al. (2021). Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance in adults with overweight or obesity: The STEP 4 randomized clinical trial. JAMA, 325(14), 1414–1425. https://doi.org/10.1001/jama.2021.3224 

2. Wharton, S, et al. (2025). Once-weekly semaglutide 7.2 mg in adults with obesity: the randomised, controlled, phase 3b STEP UP trial. 1966-LB poster. American Diabetes Association (ADA) 85th Scientific Sessions, Chicago, US, June 20 – 23, 2025.17.