All About Weight Loss Drugs: How They Work and Who Can Use Them in the UK

Comprehensive Guide to Weight Loss Drugs in the UK

Weight loss drugs, such as Wegovy, Mounjaro, and Saxenda, have gained attention as potential treatments for obesity when diet and exercise alone are insufficient. These medications are part of a broader strategy for weight management, targeting pathways that control hunger and metabolism. However, their use is strictly regulated in the UK, and they are only prescribed under certain medical circumstances. Understanding the range of options, how they work, and their suitability is crucial when considering pharmacological support for weight loss.

What Are Weight Loss Drugs?

Weight loss drugs are prescription-only medications designed to support weight loss by modifying the body’s physiological response to hunger, satiety, and energy expenditure. They are typically recommended for:

• Body Mass Index (BMI) of 30 or above, classifying as obese.
• BMI of 27 or above if accompanied by obesity-related conditions, such as Type 2 diabetes, hypertension, or obstructive sleep apnoea.

Types of Weight Loss Drugs in the UK

The most well-known weight loss medications currently approved or under consideration in the UK include:

2. 1. Wegovy (Semaglutide)

   • Class: GLP-1 Receptor Agonist
   • Mechanism: Reduces appetite and delays gastric emptying, leading to a decrease in calorie intake and prolonged satiety.
   • Use: Approved for weight management in adults with obesity or overweight and weight-related conditions.
   • - Availability: Approved by NICE and available on the NHS under strict criteria.

2. 2. Saxenda (Liraglutide)

   • Class: GLP-1 Receptor Agonist
   • Mechanism: Similar to Wegovy, Saxenda mimics GLP-1 to regulate appetite and reduce food intake.
   • Use: Recommended for individuals with a BMI of 30 or above or a BMI of 27 with comorbidities.
   • Availability: Available on private prescription and the NHS in select cases.

2. 3. Mounjaro (Tirzepatide)

   • Class: Dual GLP-1 and GIP Agonist
   • Mechanism: Targets both GLP-1 and GIP receptors to significantly impact hunger regulation, insulin sensitivity, and energy balance.
   • Use: Currently licensed for managing Type 2 diabetes; under review for weight management applications.
   • Availability: Not yet approved for weight loss in the UK.

2. 4. Orlistat (Alli, Xenical)

   • Class: Lipase Inhibitor
   • Mechanism: Blocks the absorption of dietary fats in the intestine, leading to reduced calorie intake.
   • Use: Approved for weight management in adults with obesity and available over-the-counter as Alli or on prescription as Xenical.
   • Considerations: Often used as an adjunct to diet and exercise, but may cause gastrointestinal side effects.

2. 5. Mysimba (Naltrexone/Bupropion)

   • Class: Combination Therapy
   • Mechanism: Acts on the hypothalamus and mesolimbic dopamine circuit to reduce appetite and cravings.
   • Use: Approved in the UK for weight management in adults with obesity or overweight with comorbid conditions.
   • Availability: Available on private prescription and may be prescribed off-label in select cases.

3. Other GLP-1 Receptor Agonists

   • Ozempic (Semaglutide) and Rybelsus (Oral Semaglutide) are primarily indicated for Type 2 diabetes but are sometimes used off-label for weight management.
5.  

How Do Weight Loss Drugs Work?

Most weight loss medications act by influencing pathways involved in hunger and satiety:

• GLP-1 Receptor Agonists (e.g., Wegovy, Saxenda): These drugs mimic the action of the hormone GLP-1 (Glucagon-Like Peptide-1), which increases feelings of fullness, reduces appetite, and slows gastric emptying. This leads to a lower calorie intake and aids weight reduction.
• Dual GIP and GLP-1 Agonists (e.g., Mounjaro): Target both GIP (Gastric Inhibitory Polypeptide) and GLP-1 receptors, providing dual action for enhanced appetite regulation and metabolic benefits.
• Lipase Inhibitors (e.g., Orlistat): Prevent the digestion and absorption of dietary fats, resulting in decreased energy intake.
• Combination Therapies (e.g., Mysimba): Act on multiple brain pathways to reduce hunger and cravings, supporting a holistic approach to weight loss.

UK Regulations and Eligibility Criteria

In the UK, the use of weight loss medications is strictly regulated:

• Wegovy: Approved for use in adults with a BMI of ≥35 kg/m², or ≥30 kg/m² with at least one weight-related comorbidity (e.g., hypertension, dyslipidaemia). Accessible on the NHS when criteria are met.
• Saxenda: Recommended for patients with a BMI ≥30 kg/m² or ≥27 kg/m² with a weight-related condition.
• Orlistat: Available over-the-counter for patients with a BMI ≥28 kg/m² or on prescription for BMI ≥30 kg/m².
• Mounjaro: Currently not approved for weight management; used in Type 2 diabetes management.

Considerations and Potential Side Effects

Like all medications, weight loss drugs have potential side effects, including:

• GLP-1 Receptor Agonists: Nausea, vomiting, diarrhoea, or constipation. Typically, these diminish over time.
• Orlistat: Gastrointestinal issues such as oily stools, flatulence, and frequent bowel movements.
• Mysimba: Dizziness, dry mouth, and elevated heart rate.

Weight loss medications should be avoided in patients with:

• Personal or family history of medullary thyroid carcinoma (MTC).
• Pancreatitis or severe gastrointestinal diseases.
• Pregnancy or breastfeeding.
• Severe eating disorders.

Choosing the Right Weight Loss Treatment

Pharmacological support should be part of a comprehensive weight management plan, including:

1. Nutritional guidance.
2. Physical activity.
3. Behavioral therapy.
4. Regular follow-ups to assess progress and side effects.

Find the Right Weight Loss Treatment through CompareHealth

At CompareHealth, we connect you with leading UK clinics and healthcare professionals specialising in obesity management and weight loss treatments:

• Find a Specialist Near You: Search by location to find experienced clinicians.
• Compare Treatment Options: View clinic reviews, treatment costs, and specialities.
• Book Appointments Online: Save time by booking directly through our platform.

For individuals struggling with obesity, finding the right support and understanding treatment options is the first step towards a healthier lifestyle.

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