Weight loss injections in Gloucester are now one of the most searched-for health topics in the county, and at Hucclecote Pharmacy we hear questions about Mounjaro and Wegovy almost every day. Many people want to know whether they might work for them, and how to get them safely rather than from an unknown website.
These medicines can be genuinely effective for the right person, but they are prescription-only for good reason. They need a proper clinical assessment, careful dose increases, and regular monitoring. This guide explains in plain English how GLP-1 injections work, who is eligible, how Mounjaro and Wegovy compare, what side effects to expect, and why it matters where your pen comes from. If you would like to talk it through in person, our pharmacist prescriber sees patients from across Hucclecote, GL3, and the surrounding areas. For a broader look at our programme, see our earlier guide to weight management in Gloucester.
How GLP-1 injections work (a plain-English explainer)
After you eat, your gut releases hormones that tell your brain you are full and help your body manage blood sugar. One of the most important of these is GLP-1 (glucagon-like peptide-1). Weight loss injections contain medicines that copy the action of this hormone, but last far longer in the body than the natural version, which is broken down within minutes.
The main effects are:
- Reduced appetite. GLP-1 acts on the areas of the brain that control hunger, so many people feel satisfied with smaller portions and think about food less often.
- Slower stomach emptying. Food stays in the stomach longer, which helps you feel full for longer after a meal.
- Better blood sugar control. The medicine helps the pancreas release insulin when blood sugar rises, which is why these medicines were first developed for type 2 diabetes.
Wegovy contains semaglutide, which acts on the GLP-1 receptor. Mounjaro contains tirzepatide, which acts on the GLP-1 receptor and on a second hormone receptor called GIP (glucose-dependent insulinotropic polypeptide). That dual action is the main scientific difference between the two.
Both are given as a small injection under the skin once a week, using a pre-filled pen, usually into the stomach, thigh or upper arm. Treatment always starts at a low dose that increases gradually, typically every four weeks, to give your digestive system time to adjust.
These medicines are not a substitute for diet and activity changes: their UK licences require them to be used alongside a reduced-calorie diet and increased physical activity, ideally within a structured plan such as our weight management service.
Am I eligible for weight loss injections?
Eligibility for private prescribing is based on the medicines' UK licences, which are approved by the MHRA, together with a prescriber's clinical judgement. In general, you may be eligible if you are an adult and have:
- A BMI of 30 or above, or
- A BMI of 27 or above with at least one weight-related health condition, such as type 2 diabetes or prediabetes, high blood pressure, high cholesterol, obstructive sleep apnoea or heart disease.
NICE recognises that people from South Asian, Chinese, other Asian, Middle Eastern, Black African and African-Caribbean backgrounds can face higher health risks at a lower BMI, so lower thresholds may be appropriate. Your prescriber will take this into account.
Weight loss injections are not suitable for everyone. You are unlikely to be offered them if you:
- Are pregnant, breastfeeding, or planning a pregnancy
- Have had pancreatitis
- Have, or have had, an eating disorder such as anorexia or bulimia
- Have certain types of diabetic eye disease, severe digestive conditions, or serious kidney or liver problems
- Take medicines that could interact in a clinically important way, such as insulin or some diabetes tablets, without specialist input
At Hucclecote Pharmacy, your assessment includes a confidential health questionnaire, measurement of your weight, height and BMI in person, a review of your medical history, and a check of all your current medicines. If you take several regular medicines, a medication review is a useful way to make sure everything works safely together. If injections are not right for you, your prescriber will explain why and discuss other options, which may include lifestyle support alone or a referral to your GP.
Mounjaro vs Wegovy: how they compare
Both medicines are MHRA-licensed for weight management, both are once-weekly injections, and both have been studied in large clinical trials. The table below summarises the key differences.
| Wegovy | Mounjaro | |
|---|---|---|
| Active ingredient | Semaglutide | Tirzepatide |
| How it works | Acts on GLP-1 receptors | Acts on GIP and GLP-1 receptors |
| How often | Once a week | Once a week |
| Starting dose | 0.25 mg | 2.5 mg |
| Usual maintenance dose | Up to 2.4 mg | 5 mg to 15 mg, depending on response and tolerance |
| Dose increases | Every 4 weeks over around 16 weeks | Every 4 weeks or longer, in 2.5 mg steps |
| Average weight loss in major trials | Around 15% of body weight over 68 weeks (STEP 1) | Around 20% at the highest dose over 72 weeks (SURMOUNT-1) |
| Common side effects | Nausea, diarrhoea, constipation, vomiting | Nausea, diarrhoea, constipation, vomiting |
| Effect on the oral contraceptive pill | No specific MHRA warning | May reduce effectiveness; extra contraception advised |
In a 2025 head-to-head trial (SURMOUNT-5), people taking tirzepatide lost more weight on average than those taking semaglutide. However, trial averages are not predictions for any one person. Some people respond very well to Wegovy, some tolerate one medicine better than the other, and some have medical reasons that make one option more suitable.
Your other health conditions, contraception needs, supply and cost may also shape the choice, and your prescriber will talk these through rather than defaulting to one brand.
Safety, side effects and monitoring
Most side effects of GLP-1 medicines affect the digestive system and are worst in the first few weeks and after each dose increase. Common ones include nausea, diarrhoea, constipation, indigestion, burping, tiredness and sometimes vomiting. Practical steps that often help include eating smaller meals, stopping when you feel full, avoiding very fatty or rich foods, and drinking plenty of fluids.
Some side effects are less common but more serious, and you should know the warning signs:
- Pancreatitis. Severe, persistent pain in the upper stomach that may spread to the back, with or without vomiting. Stop the injection and seek urgent medical help.
- Gallbladder problems. Pain in the upper right side of the stomach, fever, or yellowing of the skin or eyes.
- Dehydration. Ongoing vomiting or diarrhoea can lead to dehydration, which can affect the kidneys. Keep drinking fluids and contact your prescriber.
- Low blood sugar. More likely if you also take insulin or certain diabetes medicines.
In 2025, the MHRA issued updated safety advice on pregnancy and contraception. These medicines should not be used in pregnancy. Wegovy should be stopped at least two months before trying to conceive, and Mounjaro at least one month before. Mounjaro may reduce the effectiveness of the oral contraceptive pill in people who are overweight or obese, so a non-oral method, or an additional barrier method for four weeks after starting and after each dose increase, is advised.
Because these medicines slow stomach emptying, tell any doctor, dentist or anaesthetist that you are taking one before a procedure involving sedation or a general anaesthetic.
At Hucclecote Pharmacy, regular check-ins record your weight, review side effects, check your blood pressure where needed, and decide whether to increase, hold or reduce your dose. Treatment is formally reviewed after around six months on a maintenance dose. If you have lost less than 5% of your starting weight by then, NICE guidance supports stopping, because the benefits are unlikely to outweigh the costs and risks.
Why choose a regulated pharmacy over online sellers
Demand for these medicines has created a large unregulated market. The MHRA has seized thousands of fake and unlicensed weight loss pens in the UK, many sold through social media, messaging apps, beauty salons and websites that ask few or no health questions. Pens from these sources may contain the wrong dose, the wrong substance, or nothing at all.
Even among legitimate online pharmacies, standards vary. Since 2025, the GPhC has required online providers to verify the information patients give them before prescribing weight loss medicines, for example through a video consultation or access to medical records, rather than relying on a questionnaire alone.
| Regulated local pharmacy | Unregulated online or social media seller | |
|---|---|---|
| Who prescribes | A registered prescriber who assesses you | Often no prescriber at all |
| Health checks | In-person weight, BMI and medical history | Self-reported or none |
| Product source | Licensed UK supply chain | Unknown; risk of counterfeit or unlicensed pens |
| Follow-up | Regular reviews and dose adjustments | Usually none |
| Accountability | GPhC-registered premises and pharmacists | No clear accountability |
If you choose an online provider, check that the pharmacy and the pharmacist appear on the GPhC online register, and be cautious of any seller who does not ask about your health history and other medicines. You can report suspected fake products through the MHRA Yellow Card scheme.
A local pharmacy also offers something a website cannot: a team you can walk in and speak to. The same pharmacists who look after your NHS prescriptions and provide services such as Pharmacy First can see you face to face if you have a side effect or a question about your dose.
Starting weight loss injections at Hucclecote Pharmacy in Gloucester
If you are considering Mounjaro or Wegovy in Gloucester, the first step is a private consultation with our pharmacist prescriber. You do not need a GP referral. The process usually looks like this:
- Book an initial consultation. Use our online booking page, call us, or ask in the pharmacy.
- Assessment. In our private consultation room, we measure your weight, height and BMI, go through your medical history and current medicines, and discuss your goals.
- Treatment plan. If injections are suitable, your prescriber explains the options, how to inject, how to store your pens, what side effects to expect, and when to get in touch. If they are not suitable, we will explain why and discuss alternatives.
- Ongoing reviews. Regular follow-ups to adjust your dose, monitor progress and support diet and activity changes, as part of our weight management service.
NHS access to these medicines is expanding but remains limited. Wegovy is mainly available through specialist NHS weight management services, and Mounjaro is being introduced in primary care gradually, starting with people at the highest clinical need. If you think you may qualify for NHS treatment, it is worth speaking to your GP as well.
As a GLP-1 pharmacy in Gloucester, we see patients from Hucclecote, Brockworth, Abbeydale, Barnwood, Longlevens and across the city. You can browse all our services or contact us for current pricing. All consultations are confidential, and you will never be pressured into starting treatment.
Frequently Asked Questions
What's the difference between Mounjaro and Wegovy?
Both are once-weekly injections licensed in the UK for weight management. Wegovy contains semaglutide, which mimics one gut hormone (GLP-1). Mounjaro contains tirzepatide, which acts on two hormone receptors (GIP and GLP-1). In clinical trials, including a head-to-head study, average weight loss was greater with Mounjaro, but both can be effective, and the right choice depends on your health, other medicines and how you tolerate treatment.
Who can be prescribed weight loss injections in the UK?
Under their UK licences, Mounjaro and Wegovy are for adults with a BMI of 30 or above, or 27 or above with at least one weight-related condition such as type 2 diabetes, high blood pressure or high cholesterol. Lower BMI thresholds may apply for people from some ethnic backgrounds. Treatment must be part of a plan that includes diet and activity changes, and a prescriber must confirm it is safe for you.
How much do Mounjaro and Wegovy cost in Gloucester?
The cost of private weight loss injections depends on the medicine, the dose you are on and the level of clinical support included, and manufacturer prices can change. Please contact Hucclecote Pharmacy for current pricing before you commit to anything. Be wary of websites or social media sellers offering prices far below the norm, as unusually cheap pens are a common sign of unlicensed or counterfeit products.
Is it safe to buy weight loss injections online?
It can be, but only from a registered UK pharmacy that carries out a proper clinical assessment and verifies your details. The MHRA has warned that fake and unlicensed weight loss pens are being sold through social media, beauty salons and unregulated websites. Before ordering anywhere, check the pharmacy on the GPhC online register, and never buy from a seller who does not ask about your health and other medicines.
How long do I need to stay on the medication?
There is no single answer. Treatment is usually reviewed after about six months on the maintenance dose, and if you have lost less than 5% of your starting weight, your prescriber may suggest stopping. Studies show that many people regain weight after stopping, so the plan for diet, activity and eventually coming off treatment matters as much as the injections themselves. Your prescriber will review this with you regularly.
What are the most common side effects?
The most common side effects are digestive: nausea, diarrhoea, constipation, indigestion and sometimes vomiting, especially when starting or increasing the dose. They often ease over a few weeks. Less common but serious problems include pancreatitis and gallbladder problems. Seek urgent medical help for severe, persistent stomach pain that may spread to your back, and keep well hydrated if you have vomiting or diarrhoea.
Can I use weight loss injections if I'm planning a pregnancy?
No. The MHRA advises that these medicines should not be used during pregnancy or while trying to conceive. Wegovy should be stopped at least two months before trying for a baby, and Mounjaro at least one month before. Mounjaro may also make the oral contraceptive pill less effective in people who are overweight, so additional or non-oral contraception is advised. Discuss your plans with your prescriber before starting.
About the Author
This article was written by Ravneet Chahal, Pharmacist Prescriber and Superintendent Pharmacist at Hucclecote Pharmacy, Gloucester. Ravneet is registered with the General Pharmaceutical Council (GPhC registration number 2079107) and has 13+ years of experience supporting patients across Gloucestershire with NHS and private pharmacy services.
All content is reviewed for accuracy against NHS, NICE, and MHRA guidance.
Book at Hucclecote Pharmacy
Ready to take the next step? Our team in Hucclecote, Gloucester is here to help.
- Learn more about our private weight management service
- Book online at hucclecotepharmacy.co.uk/booking
- Call us on 01452 616906
- Visit Hucclecote Pharmacy, Gloucester GL3
Same-week appointments often available. No GP referral needed for private services.
About Ravneet Chahal
Ravneet Chahal is a highly qualified Pharmacist Prescriber at Hucclecote Pharmacy with extensive professional credentials and expertise in clinical pharmacy practice.
Qualifications: MPharm, PGDip, PGCert IP, MCMA
With her specialized knowledge and prescribing authority, Ravneet is committed to providing evidence-based health information and personalized pharmaceutical care. She supports our patients in making informed decisions about their health and wellness.
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