What is Ozempic? What it is, how it works and possible side effects

Ozempic is a weekly injection for type 2 diabetes. Its active ingredient, semaglutide, helps your body to manage blood sugar more effectively.

It’s licensed in the UK to treat type 2 diabetes and is taken once a week, usually alongside changes to diet and other medication. As it’s a prescription-only medicine (or POM for short), you’ll only get it on prescription after your doctor has checked whether it’s right for you.

Mumsnet users often swap their Ozempic stories on the Talk boards. There are discussions around whether Ozempic can be used for weight management: in the UK, Ozempic isn’t licensed for weight management and using it for that reason would be considered off-label use. For weight management, the licensed brand is Wegovy (semaglutide 2.4 mg) as per NICE guidelines.

We’ll go into more detail about how Ozempic works in this guide with the help of expert Dr Daniel Atkinson, clinical lead at Treated, but in short: it mimics a natural hormone that helps regulate blood sugar.

However, like all medications, it can come with side effects and it’s not for everyone, so it’s worth knowing how it works, who usually gets prescribed it and what to expect along the way.

Here’s what we’ll cover

• How Ozempic works

• Who it’s usually prescribed for 

• How to take it

• Side effects and safety information

• What to expect from treatment

• What Mumsnet users say about Ozempic

• Who to speak to while you’re on it 

• Where to find more information 

What is Ozempic and how does it work? 

Semaglutide belongs to a group of medicines called GLP-1 receptor agonists. They copy the action of a hormone (called glucagon-like peptide-1) that your body naturally produces after you eat.

Dr Daniel explains: “Ozempic is a diabetes treatment in an injectable pen. It belongs to a group of medications known as GLP-1 receptor agonists. Ozempic works by regulating insulin secretion and reducing your appetite.

“Eating less means you can balance your blood sugar levels, controlling your symptoms and managing the condition more easily.

“GLP-1 receptor agonists work by binding to GLP-1 receptors. This normally happens after you’ve eaten. By mimicking the effects of this hormone, the medication ‘tricks’ your brain into thinking you’re full, and suppresses hunger signals.”

Ozempic helps control blood sugar in three main ways:

• Stimulating insulin production

• Reducing glucose output

• Slowing digestion

But remember: It’s not insulin and doesn’t replace insulin. Instead, it helps your body regulate blood sugar more effectively.

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Ozempic vs Wegovy vs Rybelsus

“All three medications contain semaglutide”, says Dr Daniel. “Like Ozempic, Rybelsus is prescribed to manage diabetes, but comes in the form of a daily tablet. 

“Wegovy is an injectable pen, but is licensed as a weight [management] treatment.”

Who might be prescribed Ozempic?

Doctors follow the National Institute for Health and Care Excellence (NICE) guidelines when prescribing semaglutide. It’s usually considered when: 

• Other type 2 diabetes treatments haven’t worked (like metformin)

• You have a BMI of 35+ with weight related health issues

• You have a BMI under 35 but insulin would affect your job or weight loss would improve another serious condition 

 Dr Daniel clarifies: “Ozempic is licensed as a diabetes treatment in the UK. It’s recommended that patients use it as part of a treatment plan that involves eating a balanced, varied diet, and increasing the amount of exercise they do.”

After all, Ozempic isn’t a first-line treatment. It’s usually prescribed when other medicines, like metformin, haven’t worked. While some people lose weight on it, the main aim is blood sugar control.

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Your doctor will look at your full health picture before prescribing it: medical history, other medicines you’re on, your lifestyle and what you want from treatment.

Dr Daniel explains: “This can involve things like interactions with other medications you’re taking, and whether using Ozempic might put your health at risk. Pregnant women, for example, should avoid using Ozempic.”

In fact, because semaglutide has a long half-life, treatment should be stopped at least 2 months before a planned pregnancy.

Important safety considerations

Ozempic isn’t safe for everyone.

Contraindications in the UK for Ozempic include any known hypersensitivity to semaglutide or any of its ingredients. In the US, it’s also advised against use in people with “a history of medullary thyroid cancer (MTC) or Multiple endocrine neoplasia type 2 (MEN2) in your family, or if you have either condition”, Dr Daniel explains. 

Additionally, Ozempic should not be used for type 1 diabetes or to treat diabetic ketoacidosis (DKA). When used alongside insulin, doses should not be reduced abruptly, as this can actually increase the risk of DKA.

Regarding pregnancy and breastfeeding, he advises: “More research is needed on the impact Ozempic can have on pregnancy, fertility and breastfeeding, but it generally wouldn’t be prescribed to anyone who falls under this criteria because of potential risks.”

If you're planning to become pregnant in the near future, make sure you mention this in any conversations with your healthcare provider about Ozempic.

Other medications: make sure to tell your doctor about everything you take - prescription medicines, over-the-counter drugs like painkillers, and even vitamins or supplements. Some of these might not work well together with semaglutide.

Medical conditions: some health conditions mean you shouldn't take semaglutide at all. Your healthcare provider will check if you have any medical issues that would make this medication unsafe for you.

Being fully transparent with your medical history and health is important

How is Ozempic taken?

Ozempic comes in a pre-filled pen, injected once a week into the layer of fat just under the skin.

Dr Daniel explains how patients are taught to use it: “Ozempic is self-administered, so you inject it yourself once a week. It’s a subcutaneous injection, which means it’s applied to the layer of fat just beneath your skin.

“When you’re prescribed Ozempic, a clinician should talk you through how to use the injections, and there’s also a guide on the patient information leaflet that comes with the medication. You’ll also typically be advised about any side effects you might experience.”

Common injection sites include: 

• The front of the thigh

• The stomach (not too close to the belly button)

• The back of the upper arm (if someone else is giving the injection)

Rotate sites each week to avoid skin irritation.

You usually start on a low dose, which may be increased gradually to reduce side effects while still keeping blood sugar under control.

Starting your dose

Treatment usually starts at 0.25 mg once weekly for four weeks, then increases to 0.5 mg once weekly. If further control is needed, your doctor may increase the dose to 1 mg, and then up to a maximum of 2 mg weekly.

If you miss a dose and it’s been less than five days, you should take it as soon as possible. If more than five days have passed, skip the missed dose and take the next one at your usual time.

Dr Daniel says: “Your prescriber should check if any side effects you get are manageable, and if you’re happy with your dosage schedule. 

“Your blood sugar levels should be checked every few weeks to see if Ozempic is working, and make sure you’re on the right dose.”

Side effects and safety information

Like most medicines, Ozempic can cause side effects. Some are mild and pass quickly, whereas others need medical attention. Here’s what to look out for. 

“Common side effects include nausea, diarrhoea and vomiting,” shares Dr Daniel. “Side effects tend to affect people to varying extents though, and might differ person-to-person.

“Side effects should settle down as you adjust to the medication. You might find they start up again as you switch doses, but they’re usually tolerable and won’t continue long-term.”

Common side effects may include: 

• Feeling sick (nausea)

• Vomiting

• Diarrhoea

• Constipation

• Abdominal pain

• Reduced appetite

• Fatigue

For managing digestion issues, he advises: “Often, I’ll recommend patients try to avoid any foods that might exacerbate any side effects they get. 

“This might mean skipping particularly rich or spicy foods, and sticking to smaller, simpler meals. Taking walks outside in fresh air and drinking plenty of water can be helpful, too.”

Serious side effects (seek urgent help)

More serious side effects are less common but require immediate medical attention if you experience them. These can include: 

• Signs of pancreatitis (severe abdominal pain that may spread to your back)

• Symptoms of low blood sugar when used with insulin or other diabetes medications

• High blood sugar (that can cause diabetic ketoacidosis (DKA))

• Allergic reactions

If you already have diabetic retinopathy and are also taking insulin, you may be at a higher risk of complications when starting Ozempic. Your doctor may recommend more frequent eye checks while you’re on treatment.

“Like most medicines, Ozempic does have the potential to cause severe allergic (anaphylactic) reactions,” Dr Daniel shares. “For Ozempic, these are considered rare (affecting 1 in 1000 people) and would require urgent medical attention.”

! This is not a full list of side effects. You will get a full list of known side effects in the Patient Information Leaflet (PIL) that comes with your medication box. 

Missed doses

If you miss a dose and it’s been less than five days, you can usually take it as soon as you remember. If more than five days have passed, skip it and carry on with your normal schedule.

Always follow the instructions in your PIL or check with your doctor. You can also report any side effects via the Yellow Card Scheme.

Ozempic can be injected in three areas - your stomach, thigh or upper arm

What to expect from treatment

Ozempic can improve blood sugar control and reduce appetite, but it works best alongside diet and exercise.

“One misconception is that Ozempic is a weight loss medication, when it’s only used off-label for this reason,” explains Dr Daniel. “It’s designed to help patients manage diabetes, but its effects on weight loss tends to be the focus of most news stories that cover it.”

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In reality, the main Ozempic benefits are:

• Improved blood sugar control

• Appetite regulation

• Support for lifestyle changes

Of course, everyone responds differently to the medication. Your blood sugar levels may improve slowly over time, and you’ll need regular check-ups to see how well it’s working. Eating well and staying active are still really important

Remember: It won’t cure diabetes, but it can make managing it easier when used as part of a full treatment plan. Your doctor will monitor your progress and may adjust your dose.

What Mumsnet users say about Ozempic

On the Talk boards, users swap stories about Ozempic - from curbing food cravings to dealing with side effects. Experiences vary, but a few themes keep coming up.* 

Appetite changes: Many say they feel less hungry and have fewer constant thoughts about food (“food noise”).

“I'm on 0.5 Ozempic and definitely notice the effects - my appetite is considerably reduced and I get satiated quickly. My chocolate drawer in the fridge hasn't been touched since I started using it!” thornbury

Helpful tool, not a cure: Users stress you still need to stick to lifestyle changes.

Tips and support: People swap ideas for managing side effects, finding good doctors and getting prescriptions safely.

“It was some friends of mine telling me about their Ozempic experience that helped me go from curious to trying it for myself and it’s been a godsend for me. I don’t try and talk people into it but I’m happy to share my experience with it.” frogpigdonkey

Side effects: Experiences range from mild tummy upsets to more serious issues.

Being realistic about results: Results vary, and weight changes aren’t guaranteed.

“I've been on it and metformin since [the] end of June last year. For me it was a very very last resort. I'd been trying to lose weight for 14 years. [...] So as a very last resort I tried it and it's worked. My dr is in constant contact and I'm monitored closely. So for me it's worth it [...]” Unkownone

Finally, it's important to remember that while some users talk about weight changes, doctors prescribe semaglutide mainly to help control blood sugar in diabetes. Any weight loss is a bonus, not the main goal.

Who should you speak to during treatment?

While you’re taking Ozempic, it’s really important to stay in regular touch with your medical team. They can:

• Check how well Ozempic is working

• Adjust your dose if needed

• Help with side effects

• Make sure it’s safe with your other treatments

• Answer questions as they come up

Contact your team if:

• Side effects don’t go away or get worse

• You’re worried about blood sugar levels

• You’re prescribed a new medicine
  Your health changes

• You’re planning a pregnancy

Important: Never buy semaglutide from dodgy websites or sellers who don’t ask for a prescription. It must be prescribed and monitored by a qualified professional.

Make sure you get your Ozempic injections from regulated, trusted providers

Useful links for more information

For additional information about diabetes management and treatment options:

NHS resources

• NHS: Obesity treatment

• NHS England: Digital weight management

• NHS: Type 2 diabetes

Professional organisations

• Diabetes UK: Provides comprehensive information and support for people with diabetes

• NICE Guidelines: Official treatment recommendations for healthcare professionals

Reporting concerns

• Yellow Card Scheme: For reporting medication side effects

• MHRA: For general medication safety information

Always consult your healthcare provider for personalised medical advice regarding your diabetes management and treatment options.

About the expert

• Dr Daniel Atkinson is the Clinical Lead at Treated.com, an online healthcare service company.

About the author

Our resident Leeds lass, Rebecca Roberts is a Senior Content Editor here at Mumsnet. On a daily basis, she commissions, writes and edits content designed to help parents navigate real life - from product reviews to practical features on everything from sex and relationships to fashion to skincare.

Rebecca - aka Beccy - brings unique personal insight to weight loss content here at Mumsnet, having undergone her own journey with medically supervised injections. Her firsthand experience with GLP-1 treatments provides authentic expertise that resonates with parents exploring similar options. 

Beyond her role as an editor, she can be found balancing life as a working mum of two toddlers and when she’s not at her desk, you’ll likely find her at a PTA meeting, in a nearby coffee shop, or walking her two dogs up and down country lanes.

*MumsGPT 1 July 2024 - 25 July 2025