Abodee Alhasso

Pharmacist · Independent Prescriber

Your Weight Loss Guide

I've put together everything you need to know about weight loss medications available in the UK — from GLP-1 agonists to oral options. This is the guide I wish every patient had before starting treatment.

How Do Weight Loss Medications Work?

Several classes of prescription medication are available in the UK for weight management. The most effective are GLP-1 receptor agonists, which mimic the natural GLP-1 hormone. Other options include lipase inhibitors like Orlistat, which reduce fat absorption.

  • GLP-1 agonists — slow gastric emptying, reduce appetite via brain signalling, and improve insulin sensitivity

  • Dual GIP/GLP-1 agonists — target two incretin pathways for enhanced weight loss (tirzepatide)

  • Triple GIP/GLP-1/Glucagon agonists — the next frontier, targeting three receptors for potentially greater weight loss and metabolic benefit (retatrutide, currently in Phase 3 trials)

  • Oral semaglutide — a tablet form of GLP-1 agonist, taken daily on an empty stomach

  • Orlistat — blocks pancreatic lipase, preventing ~30% of dietary fat from being absorbed

  • Some GLP-1s may also reduce cardiovascular risk (demonstrated in the SELECT trial for semaglutide)

Reference

Medication comparison

Licensed and investigational treatments for weight management, with average total body weight loss from the pivotal trials. Figures are trial means, not a guide to what any one person will achieve.

Practitioner reference This table names prescription-only medicines and is intended for clinical and internal use. It is not for the public-facing site.

Scroll or tap through each medicine below

Medication Type Mechanism Avg weight loss CV benefit Dosing
Established in outcome trials Emerging or partial evidence No demonstrated benefit

Sources. SURMOUNT-1 (Jastreboff et al., NEJM 2022). Retatrutide Phase 2 (Jastreboff et al., NEJM 2023). STEP-1 and STEP-5 (Wilding et al., NEJM 2021). SELECT (Lincoff et al., NEJM 2023). PIONEER programme. SCALE (Pi-Sunyer et al., NEJM 2015). LEADER (Marso et al., NEJM 2016). XENDOS (Torgerson et al., Diabetes Care 2004). NICE TA875, TA924, CG189.

Please note. Weight loss figures are trial averages over 56 to 72 weeks, achieved alongside diet and exercise support. Individual results vary considerably. Licensing differs by product and by indication, and not every medicine listed is licensed in the UK for weight management. Suitability is assessed individually by a prescriber.