Victoza (liraglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist used to improve blood sugar control in adults and children aged 10 years and above with type 2 diabetes mellitus. Understanding how Victoza works is essential for patients and healthcare professionals alike. This once-daily injectable medication mimics a naturally occurring hormone, stimulating insulin secretion when blood glucose is elevated, suppressing glucagon release, slowing gastric emptying, and promoting satiety. Licensed by the MHRA and recommended by NICE, Victoza offers not only glycaemic control but also demonstrated cardiovascular benefits in people with established heart disease.
Quick Answer: Victoza works by mimicking GLP-1 hormone to stimulate glucose-dependent insulin secretion, suppress glucagon release, slow gastric emptying, and reduce appetite in people with type 2 diabetes.
Victoza (liraglutide) is a prescription medicine belonging to a class of drugs called glucagon-like peptide-1 (GLP-1) receptor agonists. It is primarily used to improve blood sugar control in adults with type 2 diabetes mellitus, typically alongside diet and exercise modifications. Victoza is administered as a once-daily subcutaneous injection and works by mimicking the action of a naturally occurring hormone in the body.
The medication is licensed in the UK by the Medicines and Healthcare products Regulatory Agency (MHRA) and is recommended by the National Institute for Health and Care Excellence (NICE) as a treatment option for type 2 diabetes when certain criteria are met (NICE NG28 and TA203). Victoza may be prescribed as monotherapy when metformin is contraindicated or not tolerated, or more commonly as part of combination therapy with other glucose-lowering medications such as metformin, sulfonylureas, or insulin. In the UK, Victoza is also licensed for use in children and adolescents aged 10 years and above with type 2 diabetes.
How Victoza works involves several complementary mechanisms. As a GLP-1 receptor agonist, liraglutide stimulates insulin secretion from pancreatic beta cells in a glucose-dependent manner—meaning it only triggers insulin release when blood glucose levels are elevated. Simultaneously, it suppresses the release of glucagon (a hormone that raises blood sugar) from pancreatic alpha cells. Victoza also slows gastric emptying, which reduces the rate at which glucose enters the bloodstream after meals, and acts on appetite centres in the brain to promote satiety and reduce food intake.
Beyond glycaemic control, Victoza has demonstrated cardiovascular benefits in clinical trials (specifically the LEADER trial), reducing the risk of major adverse cardiovascular events in people with type 2 diabetes and established cardiovascular disease. This additional benefit has made it an important consideration for patients with both diabetes and established cardiovascular disease.
It is important to note that while weight loss may occur with Victoza treatment, it is not licensed specifically for weight management in the UK (a higher dose formulation called Saxenda is licensed for weight management).
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Start HereVictoza is supplied in a pre-filled, multi-dose pen designed for subcutaneous injection. The medication should be injected once daily at any time of day, independent of meals, though it is advisable to administer it at approximately the same time each day for consistency. The injection can be given in the abdomen, thigh, or upper arm, and patients should rotate injection sites within the same region to reduce the risk of lipodystrophy (changes in fat tissue under the skin).
The starting dose is typically 0.6 mg once daily for at least one week. This initial lower dose is not intended to provide full glycaemic control but rather to improve gastrointestinal tolerability as the body adjusts to the medication. After one week, the dose is usually increased to 1.2 mg once daily. If additional blood sugar control is needed after at least one week on 1.2 mg, the dose may be further increased to the maximum of 1.8 mg once daily. Dose escalation should always be guided by a healthcare professional based on individual response and tolerability. If gastrointestinal side effects occur, dose increases may be delayed, or it may be appropriate to revert to a previously tolerated dose before attempting to increase again.
Important administration guidance includes:
Always inspect the solution before use—it should be clear and colourless. Do not use if cloudy or discoloured.
Store unused pens in the refrigerator (2°C to 8°C). Once in use, the pen may be stored at room temperature (below 30°C) or in the refrigerator for up to one month.
Remove and safely dispose of the needle after each injection. Never store the pen with a needle attached, as this can cause air bubbles or leakage.
Do not share your pen with anyone else, even if the needle is changed, to prevent potential transmission of infection.
If a dose is missed and it has been less than 12 hours since the usual injection time, administer it as soon as possible. If more than 12 hours have passed, skip the missed dose and resume the regular schedule. Do not take two doses within the same 24-hour period.
Patients should receive proper training from their healthcare provider or diabetes specialist nurse on injection technique, pen operation, and needle disposal before starting treatment. The manufacturer's Instructions for Use should be carefully followed.
The timeframe for experiencing the effects of Victoza varies depending on the specific outcome being measured. Blood glucose-lowering effects typically begin within the first few days of treatment, with measurable reductions in fasting blood sugar often observed within the first week. However, the full therapeutic effect on overall glycaemic control, as measured by HbA1c (a marker of average blood sugar over the previous 2–3 months), generally takes 8 to 12 weeks to become fully apparent.
In clinical trials, Victoza has demonstrated significant reductions in HbA1c levels, with average decreases ranging from 0.8% to 1.5% (9-16 mmol/mol) depending on the dose used, baseline HbA1c values, and background therapy. These improvements are typically sustained with continued treatment. Patients may also notice reductions in post-meal blood glucose spikes relatively early in treatment due to Victoza's effect on slowing gastric emptying and enhancing glucose-dependent insulin secretion.
Weight changes associated with Victoza often occur more gradually. Many patients experience modest weight loss, typically in the range of 2 to 3 kg over several months, though individual responses vary considerably. This effect is thought to result from reduced appetite and caloric intake rather than increased metabolism. Weight loss, when it occurs, usually becomes noticeable after 4 to 8 weeks of treatment and may continue gradually over 6 months or longer.
It is important to understand that Victoza is not a rapid-acting insulin and should not be used to treat diabetic ketoacidosis or acute hyperglycaemic emergencies. Regular monitoring of blood glucose levels and periodic HbA1c testing (typically every 3 to 6 months) are essential to assess treatment response. NICE guidance (NG28) recommends reviewing the effectiveness of GLP-1 receptor agonists after 6 months of treatment, with continuation only if there has been a beneficial metabolic response, typically defined as a reduction in HbA1c of at least 11 mmol/mol (1%) and weight loss of at least 3% of initial body weight.
Like all medications, Victoza can cause side effects, though not everyone experiences them. The most common adverse effects are gastrointestinal in nature and include nausea, diarrhoea, vomiting, constipation, and abdominal discomfort. These symptoms are typically most pronounced when starting treatment or increasing the dose, and often improve over time as the body adjusts. The gradual dose escalation protocol is specifically designed to minimise these effects. Eating smaller, more frequent, low-fat meals may help reduce gastrointestinal symptoms.
Hypoglycaemia (low blood sugar) is uncommon with Victoza when used alone, as its glucose-lowering effect is glucose-dependent. However, the risk increases significantly when Victoza is combined with sulfonylureas or insulin. Patients using these combinations may require dose adjustments of their other diabetes medications to reduce hypoglycaemia risk. Symptoms of hypoglycaemia include trembling, sweating, confusion, rapid heartbeat, and hunger. Patients should be educated on recognising and treating low blood sugar episodes.
Serious but rare side effects require immediate medical attention:
Pancreatitis (inflammation of the pancreas): Persistent severe abdominal pain, often radiating to the back, with or without vomiting, warrants urgent medical assessment. Victoza should be discontinued if pancreatitis is suspected.
Thyroid concerns: Animal studies have shown that liraglutide caused thyroid C-cell tumours in rodents, although the relevance to humans is uncertain. Patients should report any symptoms such as a lump in the neck, hoarseness, or difficulty swallowing. Caution is advised in people with pre-existing thyroid disease.
Gallbladder disease: GLP-1 receptor agonists have been associated with an increased risk of gallstones and cholecystitis. Patients should seek medical attention for persistent right upper abdominal pain, fever, or jaundice.
Acute kidney injury: Cases have been reported, particularly in patients experiencing severe gastrointestinal side effects leading to dehydration. Maintaining adequate hydration is important, especially during illness.
Allergic reactions: Serious allergic reactions, though rare, can occur. Symptoms include rash, itching, difficulty breathing, or swelling of the face, lips, or throat.
Important safety considerations include:
Victoza is not suitable for people with type 1 diabetes or for treating diabetic ketoacidosis.
It should be used with caution in patients with kidney or liver impairment. There is limited experience in patients with severe hepatic impairment or end-stage renal disease.
Victoza is not recommended during pregnancy or breastfeeding; women of childbearing potential should discuss contraception and family planning with their healthcare provider.
Patients should inform their doctor of all medications they are taking, as Victoza may affect the absorption of oral medications due to delayed gastric emptying.
Regular follow-up with healthcare professionals is essential to monitor treatment response, adjust doses as needed, and screen for potential complications. Patients should contact their GP or diabetes care team if they experience persistent or concerning symptoms, and seek urgent medical attention for signs of pancreatitis, severe allergic reactions, or other serious adverse effects. Suspected side effects can be reported via the MHRA Yellow Card Scheme (yellowcard.mhra.gov.uk or the Yellow Card app).
Blood glucose-lowering effects typically begin within the first few days of treatment, but the full therapeutic effect on HbA1c generally takes 8 to 12 weeks to become fully apparent.
The starting dose is typically 0.6 mg once daily for at least one week to improve tolerability, then increased to 1.2 mg daily, with a possible further increase to a maximum of 1.8 mg daily if needed.
The most common side effects are gastrointestinal, including nausea, diarrhoea, vomiting, and abdominal discomfort, which typically improve over time as the body adjusts to the medication.
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