Liraglutide for type 2 diabetes is a once-daily injectable medication that helps control blood sugar levels in adults and children aged 10 years and above. As a glucagon-like peptide-1 (GLP-1) receptor agonist, liraglutide works by enhancing insulin secretion when glucose levels are elevated, suppressing excess glucagon release, and slowing gastric emptying. Marketed as Victoza in the UK, it is recommended by NICE for patients who have not achieved adequate glycaemic control with other treatments. This article explains how liraglutide works, who can use it, dosing guidance, and its proven effectiveness in managing type 2 diabetes.

What Is Liraglutide and How Does It Work for Type 2 Diabetes?

Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for the treatment of type 2 diabetes mellitus in adults and in children and adolescents aged 10 years and above. It is marketed under the brand name Victoza for diabetes management (a separate formulation, Saxenda, is licensed for weight management) and is administered as a once-daily subcutaneous injection. Liraglutide mimics the action of naturally occurring GLP-1, an incretin hormone that plays a crucial role in glucose homeostasis.

The mechanism of action of liraglutide involves several complementary pathways that work together to improve glycaemic control. Firstly, it enhances glucose-dependent insulin secretion from pancreatic beta cells, meaning insulin is released only when blood glucose levels are elevated. This reduces the risk of hypoglycaemia compared to some other diabetes medications. Secondly, liraglutide suppresses inappropriate glucagon secretion from pancreatic alpha cells, which helps prevent excessive glucose production by the liver during and after meals.

Additionally, liraglutide slows gastric emptying, which moderates the rate at which glucose enters the bloodstream following food intake. This contributes to reduced postprandial (after-meal) glucose excursions. Many patients also experience a reduction in appetite and body weight, which can be particularly beneficial given the strong association between obesity and type 2 diabetes.

Liraglutide has a plasma half-life of approximately 13 hours, making once-daily dosing practical and effective. The medication is approved 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 adults with type 2 diabetes under specific circumstances, typically when other therapies have not achieved adequate glycaemic control. It is important to note that liraglutide is not a substitute for insulin and is not indicated for the treatment of type 1 diabetes or diabetic ketoacidosis. In children and young people, liraglutide should be initiated and managed by specialist paediatric diabetes teams.

Who Can Use Liraglutide for Type 2 Diabetes in the UK?

Liraglutide is indicated for adults with type 2 diabetes mellitus, and its use is guided by specific clinical criteria outlined in NICE guidance. According to NICE NG28 (Type 2 diabetes in adults: management), liraglutide may be considered as part of dual or triple therapy when metformin and other oral agents have not provided sufficient glycaemic control, or when certain clinical circumstances make alternative treatments less suitable. NICE recommends that a GLP-1 receptor agonist should not be combined with a DPP-4 inhibitor (such as sitagliptin or linagliptin), as both act on the incretin pathway.

NICE recommends considering GLP-1 receptor agonists like liraglutide for patients with a body mass index (BMI) of 35 kg/m² or above (adjusted for ethnicity), or for those with a lower BMI when insulin therapy would have significant occupational implications or if weight loss would benefit other obesity-related comorbidities. The guidance also suggests that GLP-1 analogues may be appropriate for patients who have not achieved target HbA1c levels despite optimal treatment with metformin and a sulfonylurea.

In the UK, liraglutide (Victoza) is also licensed for use in children and adolescents aged 10 years and above with type 2 diabetes. Paediatric use should be initiated and supervised by specialist paediatric diabetes teams, in line with NICE NG18 (Diabetes [type 1 and type 2] in children and young people).

Contraindications and cautions must be carefully considered before initiating liraglutide. According to the UK Summary of Product Characteristics (SmPC), the formal contraindication is hypersensitivity to liraglutide or any of the excipients. Liraglutide is not indicated for the treatment of type 1 diabetes or diabetic ketoacidosis. It should not be used during pregnancy; women of childbearing potential should be advised to discontinue liraglutide at least two months before a planned pregnancy or immediately if pregnancy occurs. Liraglutide is not recommended during breastfeeding, as it is not known whether it is excreted in human milk.

Important safety warnings include the risk of acute pancreatitis. Patients should be informed of the characteristic symptoms—severe, persistent abdominal pain that may radiate to the back, with or without vomiting—and advised to seek immediate medical attention if these occur. Liraglutide must be discontinued permanently if acute pancreatitis is suspected or confirmed. There is also an increased risk of gallbladder disease (cholelithiasis and cholecystitis); patients should be counselled on the signs and symptoms and advised to seek medical review if they develop them.

Liraglutide may cause gastrointestinal adverse reactions such as nausea, vomiting and diarrhoea, particularly during initial dose escalation. These can lead to dehydration, which may result in renal impairment or acute kidney injury. Patients should be advised to maintain adequate fluid intake and to seek medical advice if they experience persistent or severe gastrointestinal symptoms.

Renal impairment: No dose adjustment is required for mild to moderate renal impairment. However, use in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²) or end-stage renal disease is not recommended, as there is limited clinical experience in this population. Hepatic impairment: There is limited experience in patients with hepatic impairment, and caution is advised; liraglutide is not recommended in patients with severe hepatic impairment.

While not a formal contraindication in the UK, caution is advised in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2, and in those with a history of pancreatitis or severe gastrointestinal disease. Healthcare professionals should conduct a thorough assessment of each patient's medical history, current medications and individual circumstances before prescribing liraglutide, ensuring that the benefits outweigh potential risks.

How to Take Liraglutide: Dosage and Administration

Liraglutide is administered as a subcutaneous injection once daily at any time of day, with or without meals, though consistency in timing is recommended for optimal adherence. The medication is supplied in a pre-filled, multi-dose pen device that delivers doses of 0.6 mg, 1.2 mg or 1.8 mg. Patients should be trained on proper injection technique, including site rotation to minimise the risk of lipodystrophy and injection site reactions.

The recommended starting dose is 0.6 mg once daily for at least one week. This initial dose is not therapeutically effective but serves as a tolerability step to reduce gastrointestinal side effects, which are common when initiating GLP-1 therapy. After one week, the dose should be increased to 1.2 mg once daily. If further glycaemic control is needed after at least one week at 1.2 mg, the dose may be increased to the maximum of 1.8 mg once daily. If gastrointestinal adverse effects are not tolerated, dose escalation may be delayed by an additional week, or the dose may be temporarily reduced to the previous tolerated level.

Injection sites include the abdomen, thigh or upper arm, and patients should rotate sites within the same region to reduce injection site reactions. Before each injection, the solution should be inspected—it should be clear and colourless or almost colourless. If the solution appears cloudy, discoloured or contains particles, it should not be used.

Storage instructions: Before first use, liraglutide pens should be stored in a refrigerator (2–8°C). Do not freeze; if accidentally frozen, the pen must be discarded. Once in use, the pen may be kept at room temperature (below 30°C) or in a refrigerator for up to one month. The pen should be kept with the cap on to protect it from light. Do not store the pen with a needle attached. After use, needles must be removed and disposed of safely in a sharps container in accordance with local NHS sharps disposal arrangements. Patients must never share injection pens, even if the needle is changed, due to the risk of infection.

Missed dose advice: If a dose is missed, it should be taken as soon as remembered, provided it is within 12 hours of the usual time. If more than 12 hours have passed, the missed dose should be skipped and the next dose taken at the usual time. Patients should not take a double dose to make up for a missed dose. If three or more days have elapsed since the last dose, treatment should be restarted at 0.6 mg once daily and re-escalated according to the standard schedule to minimise gastrointestinal adverse effects.

Healthcare professionals should provide comprehensive patient education, including written information and practical demonstration, to ensure safe and effective self-administration. Patients should be advised to report any suspected side effects via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.

Effectiveness of Liraglutide in Managing Blood Sugar Levels

Clinical trial evidence demonstrates that liraglutide is highly effective in improving glycaemic control in adults with type 2 diabetes. The landmark LEAD (Liraglutide Effect and Action in Diabetes) clinical trial programme evaluated liraglutide across various treatment regimens and patient populations, consistently showing significant reductions in HbA1c levels compared to placebo and active comparators.

In the LEAD studies, liraglutide at doses of 1.2 mg and 1.8 mg daily achieved HbA1c reductions of approximately 1.0–1.5% (11–16 mmol/mol) from baseline when used as monotherapy or in combination with other glucose-lowering agents. These reductions are clinically meaningful, as even modest improvements in HbA1c are associated with reduced risk of microvascular complications such as retinopathy, nephropathy and neuropathy. Importantly, liraglutide demonstrated efficacy in reducing both fasting plasma glucose and postprandial glucose excursions.

Beyond glycaemic control, liraglutide offers additional cardiometabolic benefits. Patients typically experience weight loss, with average reductions of 2–3 kg reported in clinical trials, though individual responses vary. This can be particularly valuable given that obesity exacerbates insulin resistance and cardiovascular risk. The LEADER trial (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results), published in the New England Journal of Medicine in 2016, demonstrated that liraglutide significantly reduced the risk of major adverse cardiovascular events—including cardiovascular death, non-fatal myocardial infarction and non-fatal stroke—in patients with type 2 diabetes and established cardiovascular disease or high cardiovascular risk.

The risk of hypoglycaemia with liraglutide monotherapy is low due to its glucose-dependent mechanism of action. However, when liraglutide is combined with a sulfonylurea or insulin, the risk of hypoglycaemia increases. In these cases, dose reduction of the sulfonylurea or insulin should be considered proactively to minimise hypoglycaemic risk, and patients should be counselled on recognising and managing hypoglycaemia.

NICE recommends that GLP-1 receptor agonists (as a class) should only be continued if there is a beneficial metabolic response, defined as a reduction in HbA1c of at least 11 mmol/mol (1.0%) and weight loss of at least 3% of initial body weight at six months. If these criteria are not met, treatment should be discontinued. Regular monitoring and clinical review are essential to assess ongoing effectiveness, tolerability and adherence, and to adjust therapy as needed to achieve individualised glycaemic targets.

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