What is Semaglutide?

Thursday, February 20, 2025

Semaglutide, pronounced ‘sem-ah-glue-tied’, is a glucagon-like peptide-1 (GLP-1) receptor agonist, in simpler terms, a medication that treats diabetes and obesity.

Semaglutide is the name of the drug in Wegovy. Wegovy is the brand name.

Medicines often have more than one name - a drug name, which is the medicine's active ingredient, and a brand name. The manufacturer chooses the brand name to help with marketing. Usually, the brand name is easier to pronounce than the drug name.

Semaglutide is also the drug in Ozempic, which is only used to treat diabetes in the UK.

The drug name is also often called the generic name.

How does Semaglutide work?

This active ingredient in the Semaglutide injection UK works in different ways:

Promoting insulin production
Reduce sugar production from the liver
Slows down digestion
Suppress appetite

Helping to:

Improved blood sugar regulation
Aid weight loss
Improve cardiovascular health

Semaglutide UK for weight loss

Wegovy's active ingredient, Semaglutide, is a 'GLP-1 receptor agonist'. It mimics GLP-1, a natural hormone, and is known to help control appetite by enhancing feelings of fullness and decreasing food intake, hunger, and cravings.

People can take Semaglutide injections with a body mass index (BMI) over 30 or 27 with any underlying weight-related health condition such as diabetes.

Patients taking Semaglutide injections like Wegovy can expect to lose up to 17% of your starting body weight.

Weight loss treatments such as Semaglutide injections are most effective alongside a reduced-calorie diet and increased physical activity.

How long does Semaglutide take to work?

Semaglutide gets to work almost straight away once it is absorbed into your body, although this doesn’t mean that you will notice the effects straight away, the timeframe of these effects will vary from person to person.

Within the first month of using Semaglutide UK, it is expected to experience the following:

Reduced hunger
Reduced energy levels (This can be managed by eating the right foods)
Common side effects such as nausea or an upset stomach
A steady weight loss of 1-3lb per week
Steady blood sugar levels

It is important to note that it is also not uncommon to experience the above effects until you increase your dose.

How long does it take Semaglutide to suppress appetite?

The time it takes for these weight loss pens to start working can vary, as everyone reacts differently to medication.

Some people experience appetite suppression in the first few days to weeks after taking the Semaglutide injection, while others may not notice a change in their appetite until they take the next dose.

Semaglutide UK for diabetes

Semaglutide isn’t available from online pharmacies for type 2 diabetes unless you have an NHS prescription.

These pharmacies can only privately prescribe these pens for weight loss treatment.

If you have diabetes, specific treatments pose risks, making it important for your GP to handle the prescriptions.

You can get a Semaglutide NHS prescription for diabetes if you meet specific criteria.

The National Institute for Health and Care Excellence (NICE) advises [12] that Ozempic and Rybelsus, which are Semaglutide pens, may be prescribed on the NHS for adults with type 2 diabetes when:

Using three medications has not been effective in managing diabetes.
Or you have not been able to take the medications. This might be because of side effects or other medical conditions.

Ozempic and Rybelsus are prescribed exclusively for individuals with a Body Mass Index (BMI) of 35 or higher, mainly when they also suffer from related psychological or other medical conditions linked to obesity. However, a person with type 2 diabetes may receive a prescription for Ozempic or Rybelsus even if their BMI is below 35, provided that:

Using insulin would affect their job due to the risk of low blood sugar, also known as hypoglycemia.
Weight loss would lead to improvements in other obesity-related health issues.

Semaglutide dosage

Semaglutide is also known by the brands Wegovy, Ozempic, and Rybelsus. Each brand has different indications, preparations, and dosages.

Below, you can find different Semaglutide treatments and how they work and differ:

Brand name: Wegovy (Semaglutide)

Source: Oxford Online Pharmacy

Wegovy is the brand name for the Semaglutide injections for weight loss.

Wegovy Semaglutide pens are available in 5 different strengths: 0.25 mg, 0.5mg, 1mg, 1.7mg and 2.4mg.

The Semaglutide dose for weight loss will vary depending on your treatment stage. You must always start with the lowest dose, which is 0.25mg. You will stay on this pen for at least four weeks before increasing to the 0.5mg dose. You will continue to increase your dose as you feel necessary until you reach your maintenance dose.

Each pen contains four doses of Semaglutide, and each dose should be injected once weekly, preferably on the same day each week.

Stick to the Semaglutide weight loss dosage chart to help your body get used to the treatment and minimise the risk of unwanted side effects.

Below is an illustration of the Semaglutide dosage for weight loss chart produced by the Wegovy manufacturer Novo Nordisk:

Source: Novo Nordisk

This chart is for Semaglutide for weight loss in non-diabetic dosage. To learn more about the Semaglutide dosage chart for people with diabetes, continue reading.

Brand name: Ozempic (Semaglutide)

Image Source: Novo Nordisk

Ozempic is also a Semaglutide injection licenced for diabetes use.

Ozempic injections are one of the most well-known GLP-1 due to their popularity in the media, by now, most people would have heard about it. With many Celebrity weight loss stories claiming to be from Semaglutide Ozempic in America, this brand has gained worldwide attention.

While Ozempic pens may be used for weight loss in other countries, in the UK, Ozempic Semaglutide is an injectable medication for treating type-2 diabetes and works by managing blood sugar levels. [8]

The Ozempic Semaglutide dosage chart for diabetes will be explained to you by your doctor and your blood sugar levels will be closely monitored during your treatment, from this, your doctor will make an informed decision as to whether it's necessary to increase your dose.

The Ozempic Novo Nordisk dosage chart for diabetes can be found below:

Source: NovoMedia

Brand name: Rybelsus (Semaglutide)

Image source: Novo Nordisk

Rybelsus are Semaglutide tablets licensed for type-2 diabetes use in the UK, however, sometimes this medicine can be prescribed off-label for weight loss, but this will be at the prescriber's discretion.

These are one of the only GLP-1 treatments available in tablet form in the UK. They are a preferred option for patients who are not comfortable with injections.

The side effects of Rybelsus are similar to those associated with Semaglutide pens. However, taking medicines orally can increase the chance of experiencing systemic side effects, such as an upset stomach.

The Rybelsus Novo Nordisk dosage chart for diabetes can be found below:

Source: Rybelsus.com

Is Semaglutide safe?

Semaglutide injections are considered safe if taken as directed by your prescriber.

A study on the effectiveness and safety of Semaglutide found that it was generally well tolerated. The most frequently reported side effects were gastrointestinal problems such as nausea, vomiting, and diarrhoea, which were mainly mild to moderate and temporary.

Serious side effects were uncommon, and dropout rates due to side effects remained low, suggesting an overall favourable safety profile.

Semaglutide provides significant, sustained weight loss in overweight or obese non-diabetic individuals with a well-tolerated safety profile.

Semaglutide side effects

Like all medicines, side effects of Semaglutide are possible. However, not everyone will experience them. These Semaglutide side effects UK can vary in frequency some of them are common and affect 1 in 10 people, whereas other side effects are rare. [2]

The most common Semaglutide side effects include:

Nausea
Diarrhea
Constipation

Although these side effects are common, they shouldn’t be permanent and will gradually lessen as your body gets used to the medicine. If they persist or worsen, contact your healthcare provider.

This is not a complete list of Semaglutide side effects; the rest can be found in the patient information leaflet or the Semaglutide BNF.

How long do Semaglutide side effects last?

Semaglutide side effects are generally temporary and will lessen and eventually go away over time.

It is common for side effects to become most prominent each time you increase your dose and then gradually fade away.

If you are concerned about any of the effects you are experiencing, you should contact your doctor for more advice.

Semaglutide UK alternatives

With the growing popularity of GLP-1 medicines, there have been many developments since the introduction of the first GLP-1, with other manufacturers offering new brands with similar active ingredients, such as Eli Lily, who makes Mounjaro.

These Semaglutide alternatives work in a similar way to reduce appetite and make you feel fuller for longer, so how do they differ? Let's take a look:

Brand name: Mounjaro (Tirzepatide)

Source: Oxford Online Pharmacy

Mounjaro injections contain the active ingredient Tirzepatide, a GLP-1 agonist licenced to aid weight loss in people with a BMI of over 30 or 27 with weight-related comorbidities.

Tirzepatide vs Semaglutide - what are the differences?

Besides the apparent brand name and active ingredient difference, Tirzepatide acts slightly differently than Semaglutide.

Unlike the other weight loss pen on the market, Wegovy, which only works in one way, Mounjaro works in two different ways to support your long-term health goals.

Mounjaro makes food move more slowly through your stomach, which helps prevent big spikes in blood sugar after meals and keeps you feeling full. [1]

Another difference is the amount of weight loss you can experience, while with Semaglutide medicines, you can expect to lose up to 17% of your starting body weight, with Tirzepatide, you could expect to lose up to 22% of your starting body weight.

Apart from these two differences, the drugs work in a very similar way and the side effects you may experience are also similar.

Explore Mounjaro from Oxford Online Pharmacy

Learn more

Brand name: Nevolat (Liraglutide)

Source: Oxford Online Pharmacy

Nevolat injections contain the active ingredient Liraglutide, a GLP-1 agonist licenced to aid weight loss in people with a BMI of over 30 or 27 with weight-related comorbidities. [11]

Liraglutide vs Semaglutide - what are the differences?

Liraglutide injections work similarly to Semaglutide injections by reducing the appetite and making you feel fuller for longer, however, there are some more noticeable differences between the two.

Liraglutide helps you lose up to 11% of your starting body weight compared to 17% with Semaglutide medicines.

Liraglutide is a once-daily injection compared to once-weekly injections of Semaglutide and Tirzepatide. Due to the inconvenience of having to inject daily, the once-weekly injections have become a more popular choice.

The dosing schedule also differs, while Liraglutide is stepped in weekly dose changes and reaches the maximum dosage by week 5, Semaglutide dosage is increased monthly, and you could reach the maximum dose by month 5.