The weight loss medication Wegovy is considered safe for suitable patients when it is prescribed after a proper clinical assessment and used as directed.
Wegovy is available as a tablet and injection. Both contain Semaglutide, a GLP-1 medicine that has been assessed by the Medicines and Healthcare products Regulatory Agency (MHRA) for safety and effectiveness. The MHRA is the UK regulator that decides whether a medicine can be licensed for use. Before it approves a medicine, it reviews evidence from clinical trials and other data on the medicine’s quality, safety and effectiveness.
Wegovy was only approved for weight management after this evidence showed that the benefits of Wegovy injections and the Wegovy pill outweighed their known risks (1-3).
Here, we’ll explain what we know about the safety profile of Wegovy, how to use the medicine safely, and how to make sure you’re buying Wegovy from a reputable online pharmacy.
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In this article:
Is the weight loss treatment Wegovy safe?
What is the safety profile of Wegovy?
What are the risks of Wegovy?
What are the common side effects of Wegovy?
How can you use Wegovy safely?
Is it safe to buy Wegovy online?
Is Wegovy safe for long-term use?
Is the weight loss treatment Wegovy safe?
Broadly speaking, Wegovy is considered safe for eligible patients. Whether it is safe for you depends on your health, other medicines and individual circumstances.
All medicines carry risks, including Wegovy. The evidence reviewed as part of its UK licensing showed that the benefits of Wegovy outweigh known risks when it is used in people living with obesity, or those who are overweight and have at least one weight-related health condition (1-3).
However, certain conditions, medicines and other factors can increase those risks, and the benefits have only been established in people who meet the eligibility criteria for treatment.
For this reason, Wegovy may not be safe or suitable if you:
Do not meet the criteria for weight loss injections, or
If you have certain health conditions or take medicines that increase the risks
It is also why Wegovy is a prescription-only medicine. Before treatment can be supplied, a healthcare professional must check that you are eligible and whether anything in your medical history or current treatment could make Wegovy unsuitable for you (1-3).
What is the safety profile of Wegovy?
The safety profile of Wegovy is the overall picture of its side effects and risks, including how common they are, how serious they can be and who may be more likely to experience them.
Wegovy has a well-established safety profile because its safety has been studied in large numbers of people across several clinical trials, and the MHRA continues to review new safety information.
Clinical trials on the Wegovy injection and Wegovy pill that looked at safety include:
STEP trials – Wegovy injections: STEP 1-4 trials included 4,684 adults, with 2,652 receiving Semaglutide 2.4mg injections. These trials lasted 68 weeks, while STEP 5 followed patients for two years (4,5).
SELECT trial – Wegovy injections: SELECT involved 17,604 adults followed for an average of around 40 months. This study provided information about the longer-term safety of Semaglutide (6).
OASIS trial – Wegovy tablets: The evidence base for oral Wegovy is smaller than for injections. In the OASIS 4 trial, 205 adults received oral Semaglutide over 64 weeks. But its safety findings were generally in line with what was already known about Wegovy (7).
Wegovy’s safety profile continues to develop as more people use Semaglutide and more safety data becomes available. New information can come from:
Suspected side effects reported through the Yellow Card scheme
Reports submitted through clinical systems used by healthcare professionals
New clinical trials and observational studies
Information supplied by pharmaceutical companies
Safety data from other medicines regulators and international databases (1)
The MHRA then looks for possible “safety signals” — patterns that suggest a side effect or risk may need further investigation. If evidence changes, warnings and prescribing information can change too.
We have already seen this happen with Wegovy. In 2026, the MHRA strengthened warnings around severe pancreatitis and updated Semaglutide information to include the very rare risk of NAION, an eye condition that can cause sudden vision loss (8,9).
What are the risks of Wegovy?
The main recognised risks of Wegovy include (2,3):
Pancreatitis
Gallstones and gallbladder inflammation
Dehydration caused by severe vomiting or diarrhoea
Low blood sugar in some people with diabetes
Worsening diabetic eye disease in some people with type 2 diabetes
A very rare eye condition called NAION, which can cause sudden loss of vision
Complications around surgery because Semaglutide slows stomach emptying
For most people, Wegovy is not dangerous, and the chance of one of these serious problems happening is low.
In clinical studies, pancreatitis was reported in around 0.2% of people taking semaglutide 2.4mg injections, while gallstones occurred in around 1.6% and gallbladder inflammation in just 0.6%. Some risks are much rarer still. NAION, for example, is classed as a very rare side effect, meaning it may affect up to 1 in 10,000 people (2,3,9).
Your own risk can be higher or lower depending on your medical history, other medicines, and how well you tolerate Wegovy. Some groups may also have additional risks. The risk of low blood sugar is higher in people with type 2 diabetes who use insulin or a sulfonylurea. If you have diabetic retinopathy, eye complications are more common (2,3).
During treatment, report any severe, persistent or unusual symptoms rather than assuming they are a normal part of taking Wegovy.
What are the common side effects of Wegovy?
The most common Wegovy side effects are nausea, vomiting, diarrhoea, constipation, stomach pain and headache (2,3).
These are broadly the same whether you take Wegovy as an injection or a tablet because both contain Semaglutide. Wegovy injection and Wegovy pill side effects are also particularly likely and often worse during dose escalation but improve as your body gets used to the medicine (2,3).
For most people, side effects do not usually mean Wegovy is unsafe, but they can be uncomfortable. You may find it helps to:
Eat smaller meals and stop when you feel full
Avoid very rich or heavy meals if they make symptoms worse
Drink regularly, especially if you have diarrhoea or vomiting
Limit how much alcohol you drink on Wegovy
Increase your dose only when advised to do so
Speak to your prescriber if side effects are difficult to manage, are getting worse or are stopping you from eating or drinking normally. If you develop severe abdominal pain, repeated vomiting or signs of dehydration, you may need more urgent medical attention (2,3,8).
How can you use Wegovy safely?
To use Wegovy safely, take it exactly as prescribed and do not take extra doses or increase the dose yourself because you want faster weight loss.
Both injections and tablets follow their own Wegovy dose escalation schedule. You start on a low dose and gradually increase it over several months. This approach gives your body time to adjust to the medicine and helps reduce the risk of common side effects (2,3).
Wegovy injections are taken once a week. Wegovy tablets are taken once a day. If you use the tablet form, make sure you know how to take the Wegovy pill correctly, as following the dosing instructions helps make sure you get the intended dose of Semaglutide (2,3).
Whichever form you use, stick to your dosing schedule. If you are experiencing bad side effects or are not losing weight as expected, speak to your prescriber instead of changing the dose yourself.
It is also important to tell your prescriber if (1-3):
You start taking any new medicines
You develop a new health problem
You are planning surgery or a procedure requiring sedation
You develop severe, persistent or unusual symptoms
These can change whether Wegovy is safe to take, and your treatment may need adjusting.
Is it safe to buy Wegovy online?
You can buy Wegovy safely online, but you can’t just add it to your basket and pay. Because Wegovy is a prescription-only medicine, it can only be safely bought online from a legitimate pharmacy that carries out safety checks through an online consultation (1,10).
What happens in a weight loss consultation is usually straightforward: you’ll be asked a few questions about your health, medicines and eligibility. What we ask before we prescribe is designed to identify anything that could make Wegovy potentially unsafe for you.
If you are using an online pharmacy in Great Britain, check that the pharmacy is registered with the General Pharmaceutical Council (GPhC). Registered pharmacies must meet standards designed to make sure medicines and pharmacy services are provided safely (1,10).
You should avoid buying Wegovy anywhere that doesn’t offer clinical assessment, such as (1):
Social media accounts
Beauty salons
Unregulated websites
Private sellers offering it without a prescription
Two safety problems can happen when buying Wegovy from an illegitimate prescribing service:
Important safety checks could be missed. Even if you meet the general eligibility criteria, that does not automatically mean Wegovy is safe or suitable for you (1,10).
There is no guarantee that what you are buying is genuine Wegovy. The MHRA has warned that illegally supplied weight loss medicines may be fake, contaminated, incorrectly dosed or contain ingredients that are not listed on the packaging (11).
Be especially cautious if you find a site that sells Semaglutide powder that needs to be mixed before injection. Authorised GLP-1 medicines are supplied as pre-filled injection pens or tablets only (1).
Is Wegovy safe for long-term use?
It depends on what is meant by long-term. The longest clinical trials of Wegovy injections followed people for around 2 to 3 years, and their safety findings were in line with what was already known about Wegovy (5,6). There is little evidence on safety beyond this, and data for the newer tablets is more limited (7). Both are intended for ongoing weight management when treatment remains effective and well tolerated (2,3).
There are a few benefits of staying on treatment long-term:
In the SELECT trial, long-term Semaglutide treatment reduced the risk of major cardiovascular events by 20% in adults with overweight or obesity who already had cardiovascular disease but did not have diabetes (6).
In the STEP 1 extension, people who stopped Wegovy injections regained around two-thirds of the weight they had lost within a year (12). Many improvements in heart and metabolic risk factors also shifted back towards their starting levels.
Long-term treatment still needs regular review. Your prescriber may consider:
How much benefit you are getting from Wegovy
Whether side effects are manageable
Whether your weight or health conditions have changed
Whether you have started any new medicines
Whether you are still on the right Wegovy dose for you
Stopping Wegovy or tapering (gradually reducing) your dose should always be discussed with your prescriber first. This applies to stopping Wegovy pills and injections.
If you are considering starting Wegovy, switching from another weight loss treatment or reviewing your current treatment, Oxford Online Pharmacy can help you decide whether Wegovy injections or Wegovy tablets are the right option for you.
Start an online weight loss consultation or explore our weight loss medicines.
References
Medicines and Healthcare products Regulatory Agency. GLP-1 medicines for weight loss and diabetes: what you need to know. GOV.UK. Updated 5 February 2026.
Novo Nordisk Limited. Wegovy 1 mg FlexTouch solution for injection in pre-filled pen: Summary of Product Characteristics. electronic Medicines Compendium. Updated 22 September 2026.
Novo Nordisk Limited. Wegovy 1.5 mg tablets: Summary of Product Characteristics. electronic Medicines Compendium. Updated 16 June 2026.
Wharton S, Calanna S, Davies M, et al. Gastrointestinal tolerability of once-weekly semaglutide 2.4 mg in adults with overweight or obesity, and the relationship between gastrointestinal adverse events and weight loss. Diabetes Obes Metab. 2022;24(1):94-105.
Garvey WT, Batterham RL, Bhatta M, et al. Two-year effects of semaglutide in adults with overweight or obesity: the STEP 5 trial. Nat Med. 2022;28:2083-2091.
Lincoff AM, Brown-Frandsen K, Colhoun HM, et al. Semaglutide and cardiovascular outcomes in obesity without diabetes. N Engl J Med. 2023;389:2221-2232.
Wharton S, Lingvay I, Bogdanski P, et al. Oral semaglutide at a dose of 25 mg in adults with overweight or obesity. N Engl J Med. 2025;393:1077-1087.
Medicines and Healthcare products Regulatory Agency. GLP-1 receptor agonists and dual GLP-1/GIP receptor agonists: strengthened warnings on acute pancreatitis, including necrotising and fatal cases. Drug Safety Update. 29 January 2026.
Medicines and Healthcare products Regulatory Agency. Semaglutide (Wegovy, Ozempic and Rybelsus): risk of non-arteritic anterior ischaemic optic neuropathy (NAION). Drug Safety Update. 5 February 2026.
General Pharmaceutical Council. Guidance for registered pharmacies providing pharmacy services at a distance, including on the internet. London: GPhC; 2025.
Medicines and Healthcare products Regulatory Agency. MHRA urges public to avoid illegal online weight-loss medicines this New Year. GOV.UK. 29 December 2025.
Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564.
Eli Lilly and Company Limited. Mounjaro KwikPen solution for injection in pre-filled pen: Summary of Product Characteristics. electronic Medicines Compendium. Updated 8 September 2026.