Determining the correct GLP-1 dose is a personalised medical decision that depends on the specific medication prescribed, your treatment goals, and individual health factors. GLP-1 receptor agonists—including semaglutide (Ozempic, Wegovy, Rybelsus), dulaglutide (Trulicity), and liraglutide (Victoza, Saxenda)—are used to manage type 2 diabetes and obesity in the UK. Each medication follows a unique dose-escalation protocol, starting with a low dose and gradually increasing over several weeks to minimise side effects whilst achieving optimal glycaemic control or weight management. Your GP or diabetes specialist will determine your appropriate dose based on clinical assessment, monitoring, and NICE guidance. Never adjust your GLP-1 dose without consulting your healthcare professional.

What Are GLP-1 Medications and How Do They Work?

Glucagon-like peptide-1 (GLP-1) receptor agonists are a class of medications primarily used to manage type 2 diabetes and, in some formulations, obesity. These medicines are available as injectables and, in the case of semaglutide (Rybelsus), as an oral tablet. They mimic the action of naturally occurring GLP-1, a hormone produced in the intestine that plays a crucial role in regulating blood glucose levels and appetite.

GLP-1 medications work through several complementary mechanisms:

• Enhancing insulin secretion from pancreatic beta cells in response to elevated blood glucose

• Suppressing glucagon release, which reduces glucose production by the liver

• Slowing gastric emptying, helping you feel fuller for longer

• Acting on appetite centres in the brain to reduce hunger and food intake

In the UK, commonly prescribed GLP-1 receptor agonists include semaglutide (Ozempic, Wegovy, Rybelsus), dulaglutide (Trulicity), liraglutide (Victoza, Saxenda), lixisenatide (Lyxumia) and exenatide (Byetta, Bydureon). Each has distinct dosing schedules—some are administered daily, whilst others are given weekly or, for oral semaglutide, taken daily by mouth.

These medications are typically prescribed when lifestyle modifications and oral diabetes medications have not achieved adequate glycaemic control, or as part of a comprehensive weight management programme for eligible patients. NICE guidelines (NG28) support their use in specific clinical scenarios, particularly for patients with a BMI ≥30 kg/m² (or ≥27 kg/m² in certain ethnic groups) when HbA1c targets are not met or when weight reduction would provide significant health benefits. GLP-1 medications are not licensed for type 1 diabetes and should never replace insulin therapy.

Standard GLP-1 Dosing Guidelines in the UK

GLP-1 dosing varies considerably depending on the specific medication prescribed, the indication (diabetes or weight management), and individual patient factors. There is no single universal dose, and prescribing follows MHRA-approved product characteristics alongside NICE guidance.

For semaglutide (Ozempic) used in type 2 diabetes:

• Starting dose: 0.25 mg once weekly for 4 weeks

• Maintenance dose: Increase to 0.5 mg weekly; may escalate to 1 mg or 2 mg weekly based on glycaemic response

For oral semaglutide (Rybelsus) used in type 2 diabetes:

• Starting dose: 3 mg once daily for 30 days

• Increase to 7 mg once daily; may escalate to 14 mg based on response

• Must be taken on an empty stomach with a small sip of water (≤120 ml) and wait 30 minutes before eating, drinking or taking other oral medicines

For semaglutide (Wegovy) used in weight management:

• Gradual escalation over 16–20 weeks, starting at 0.25 mg weekly

• Target maintenance dose: 2.4 mg once weekly

• Some patients may remain on 1.7 mg if 2.4 mg is not tolerated

For dulaglutide (Trulicity):

• Starting dose: 0.75 mg once weekly

• Can be increased to 1.5 mg, 3 mg, or 4.5 mg weekly depending on response

For liraglutide (Victoza) in diabetes:

• Starting dose: 0.6 mg daily for at least one week

• Maintenance: 1.2 mg daily, with possible increase to 1.8 mg

For liraglutide (Saxenda) in weight management:

• Gradual weekly increases from 0.6 mg to a target of 3 mg daily

All GLP-1 medications follow a dose-escalation protocol to minimise gastrointestinal side effects such as nausea, vomiting, and diarrhoea. This gradual titration allows your body to adapt to the medication whilst your healthcare team monitors your response. Never adjust your dose without consulting your prescriber, as both underdosing and excessive dosing carry risks. Always follow the specific dosing instructions in your patient information leaflet.

How Your Doctor Determines the Right GLP-1 Dose for You

Determining the appropriate GLP-1 dose is a personalised process that considers multiple clinical factors. Your GP or diabetes specialist will conduct a comprehensive assessment before initiating treatment and throughout your therapy.

Key factors influencing dose selection include:

• Treatment goals: Whether the primary aim is glycaemic control, weight reduction, or cardiovascular risk reduction

• Baseline HbA1c and blood glucose levels: Higher values may eventually require higher maintenance doses

• Body weight and BMI: Particularly relevant for weight management indications

• Renal function: Most GLP-1 medications (semaglutide, liraglutide, dulaglutide) do not require dose adjustment for kidney impairment, but exenatide and lixisenatide should be used with caution or avoided in severe renal impairment

• Concurrent medications: Especially other glucose-lowering agents that might increase hypoglycaemia risk

• Previous medication tolerance: History of gastrointestinal sensitivity influences titration speed

• Cardiovascular history: Some GLP-1 medications have proven cardiovascular benefits at specific doses

• Diabetic retinopathy status: Rapid improvement in blood glucose can temporarily worsen retinopathy, particularly with semaglutide

Your doctor will typically schedule regular follow-up appointments during the initial months of treatment. These consultations allow monitoring of:

• Glycaemic control through HbA1c measurements (usually every 3–6 months)

• Weight changes and body composition

• Tolerability and adverse effects, particularly gastrointestinal symptoms

• Blood pressure and heart rate

• Renal function tests

NICE recommends (NG28) that GLP-1 therapy should be continued only if there is demonstrable benefit—typically defined as an HbA1c reduction of at least 11 mmol/mol (1.0%) and weight loss of at least 3% of initial body weight at six months for diabetes indications. Your prescriber uses these objective measures alongside your reported quality of life to determine whether your current dose is optimal or requires adjustment.

If you are planning pregnancy, discuss this with your doctor as GLP-1 medications are not recommended during pregnancy or breastfeeding. For semaglutide, a washout period of at least 2 months before conception is advised.

Adjusting Your GLP-1 Dose: What to Expect Over Time

Dose adjustments are a normal part of GLP-1 therapy and should always be guided by your healthcare professional. The titration process is designed to balance therapeutic effectiveness with tolerability.

Initial titration phase (weeks 1–16): During this period, you will follow a predetermined escalation schedule. Each dose increase typically occurs at 4-week intervals, allowing adequate time to assess tolerance. It is common to experience mild nausea or reduced appetite during the first few days after each increase, but these symptoms usually diminish within 1–2 weeks.

Maintenance phase: Once you reach your target dose, most patients remain on this dose long-term. However, adjustments may be considered if:

• Glycaemic targets are not achieved: Your doctor may increase to the next available dose strength

• Intolerable side effects persist: A temporary dose reduction or slower titration may be appropriate

• Weight loss plateaus (for weight management indications): Dose optimisation may be discussed

• Renal function changes: Monitoring may be increased, though most GLP-1s don't require dose adjustment

• Other medications are added or removed: Particularly other glucose-lowering agents

Important considerations during dose changes:

• Never skip doses or double up if you miss an injection—follow the specific guidance in your patient information leaflet

• For missed doses, each product has different instructions:

• Semaglutide (Ozempic/Wegovy): If within 5 days, take as soon as possible; if more than 5 days, skip that dose
• Dulaglutide (Trulicity): If within 3 days, take as soon as possible; if more than 3 days, skip that dose

• Daily GLP-1s: If you miss a dose, follow your PIL instructions

• If you take insulin or sulfonylureas alongside GLP-1 medications, do not adjust these doses yourself without medical advice, as this could increase hypoglycaemia risk

• Report persistent side effects to your GP rather than stopping treatment abruptly

Some patients may require dose adjustment if they develop acute illness, undergo surgery, or experience significant changes in kidney function. For planned surgery, follow your surgical team's instructions regarding your GLP-1 medication; it may need to be temporarily paused due to its effects on gastric emptying. Your healthcare team will provide clear instructions for these situations.

Safety Considerations and When to Contact Your GP

GLP-1 medications are generally well-tolerated, but understanding potential adverse effects and safety signals is essential for all patients.

Very common side effects (affecting more than 1 in 10 people) include:

• Nausea, vomiting, and diarrhoea (usually temporary)

• Reduced appetite

Common side effects (affecting up to 1 in 10 people) include:

• Constipation

• Abdominal pain or discomfort

• Headache

• Injection site reactions

• Fatigue

Contact your GP promptly if you experience:

• Persistent or severe abdominal pain, particularly if radiating to the back—this may indicate pancreatitis

• Persistent vomiting that prevents adequate fluid intake

• Signs of dehydration: reduced urination, dizziness, dry mouth

• Symptoms of hypoglycaemia (if taking alongside insulin or sulphonylureas): trembling, sweating, confusion, rapid heartbeat

• Visual changes or eye pain, especially if you have diabetic retinopathy

• Unexplained weight loss exceeding expected therapeutic effect

• Mood changes or thoughts of self-harm

• Right upper abdominal pain, yellowing of skin/eyes, or dark urine which may indicate gallbladder problems

Seek immediate medical attention (call 999 or attend A&E) if you develop:

• Severe, persistent abdominal pain with vomiting

• Signs of severe allergic reaction: difficulty breathing, facial swelling, severe rash

• Symptoms of diabetic ketoacidosis (particularly if insulin doses have been reduced): excessive thirst, frequent urination, confusion, fruity breath odour

• Severe hypoglycaemia with loss of consciousness

Important safety information:

GLP-1 medications are not recommended during pregnancy or breastfeeding. If you are planning pregnancy, discuss with your doctor the need to stop treatment beforehand (at least 2 months before conception for semaglutide).

Always inform your healthcare team about all medications you take, including over-the-counter products. GLP-1 medications can delay gastric emptying, potentially affecting the absorption of oral medications. Never share your GLP-1 pen with others, even if the needle is changed, due to infection risk. Store your medication according to the patient information leaflet, and attend all scheduled monitoring appointments to ensure safe, effective treatment.

If you suspect you've experienced a side effect from your medication, you can report it through the MHRA Yellow Card scheme (search 'MHRA Yellow Card' or visit yellowcard.mhra.gov.uk).

Frequently Asked Questions