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Weight loss injections: a pharmacist-prescriber's honest guide

Written by Ali Aghaei · GPhC, MPharm, IPresc
Clinically reviewed by Ali Aghaei · Chief Pharmacist & Independent Prescriber
· Reviewed 1 August 2026 · 9 min read
Annotated diagram to be supplied — Diagram of how GLP-1 receptor agonists act on appetite signalling in the brain and gut
How GLP-1 medicines act on appetite signalling in the brain, stomach and pancreas.

Weight loss injections are GLP-1 receptor agonist medicines, such as semaglutide and tirzepatide, that reduce appetite and slow stomach emptying. Prescribed and monitored properly, they typically support 10 to 20 per cent weight loss over a year. At LPHG a pharmacist-prescriber consultation is £195, with no GP referral needed.

What weight loss injections actually are

“Weight loss injections” almost always means a GLP-1 receptor agonist — a medicine that mimics a natural gut hormone, glucagon-like peptide-1. The two in widest use are semaglutide (Wegovy) and tirzepatide (Mounjaro, which also acts on a second hormone, GIP). They are given as a once-weekly injection under the skin.

They are not fat-dissolving injections, and they are not a shortcut around nutrition and movement. They work by changing appetite.

What they show works — and what they cannot do

GLP-1 medicines reduce hunger, increase fullness after meals, and slow how quickly the stomach empties. For most people that means eating less without the constant battle against appetite. What they cannot do is replace the assessment, monitoring and maintenance planning that make weight loss safe and durable.

Why a prescriber-led service matters

These are prescription-only medicines for good reason. A proper service checks your BMI and history, screens for conditions where they are unsafe, starts at a low dose and titrates upward to manage side effects, and monitors you over time. Buying online without assessment skips every one of those safeguards.

How to prepare for your consultation

Bring a list of your current medicines, any recent blood results, and a sense of what you have already tried. If you have a personal or family history of thyroid or pancreatic disease, tell your prescriber — it changes what is safe to offer.

Understanding the costs

The honest market picture: prescriber-led GLP-1 services in London typically run from around £150 to £250 for an initial consultation, with medication charged separately. Prices vary widely, and the cheapest online options usually skip the clinical assessment that keeps you safe.

The metabolic bigger picture

Excess weight rarely travels alone. Fatty liver, raised blood pressure and disordered glucose often move together. Many patients pair a weight consultation with a baseline check of liver and metabolic health, which is why our weight-management pathway sits alongside imaging and blood testing rather than in isolation.

Book a weight management consultation

From £195. Report within 24 hours. No GP referral needed.

Frequently asked questions

How much weight can I expect to lose?

In clinical trials, semaglutide supported around 15 per cent average body weight loss over 68 weeks and tirzepatide up to around 20 per cent, alongside diet and activity changes. Individual results vary, and weight is regained if the medicine is stopped without a maintenance plan.

Do I need a GP referral to start?

No. You can book a pharmacist-prescriber consultation directly. We take a full history, check your BMI and any relevant bloods, and only prescribe when it is clinically appropriate and safe.

What does it cost at LPHG?

The initial pharmacist-prescriber consultation is £195. Medication and follow-up are quoted transparently at your appointment; we do not mark up hidden fees or tie you into a contract.

Who should not take GLP-1 injections?

They are not suitable in pregnancy or when trying to conceive, in certain thyroid cancer syndromes, or with some pancreatic conditions. Your prescriber will review your history to check suitability.

What are the common side effects?

Nausea, constipation and reflux are common early on and usually settle as the dose is increased slowly. Serious side effects are uncommon but we review you regularly to catch them early.

Is this the same as buying online?

No. A prescriber-led service means a proper assessment, dose titration, monitoring and a maintenance plan. Buying GLP-1 medicines without assessment is unsafe and increasingly restricted.

Will I regain the weight if I stop?

Some regain is likely if the medicine stops without a structured maintenance plan. We focus on habits, nutrition and a step-down strategy so gains are sustained.

References

  1. NICE TA875 — Semaglutide for managing overweight and obesity (2023)
  2. NICE TA1026 — Tirzepatide for managing overweight and obesity (2024)
  3. NHS — Semaglutide (Wegovy) for weight loss

Author

Ali Aghaei

Chief Pharmacist & Independent Prescriber · GPhC, MPharm, IPresc

Ali is an independent prescribing pharmacist who leads LPHG's pharmacist-led weight management service, with a special interest in GLP-1 pathways and metabolic health.

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Clinical reviewer

Ali Aghaei

Chief Pharmacist & Independent Prescriber · GPhC, MPharm, IPresc

View profile →

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