Weight Loss Medication

Weight loss medications include prescription and over-the-counter drugs designed to support weight loss in people with obesity or weight-related health conditions. These medications typically work by either regulating appetite, slowing digestion, or blocking fat absorption.

They are used alongside a healthy diet and increased physical activity and are suitable for people who have a BMI of 30 or higher, or 27+ with other health conditions like type 2 diabetes.

Weight-loss medication can be an effective option for adults whose BMI is 30 kg/m² or higher, or 27 kg/m² or higher with health risks such as high blood pressure, sleep apnoea, or type 2 diabetes. These treatments work best when combined with nutrition, exercise, and behavioural support.

Weight-loss medications influence appetite, digestion, or nutrient absorption.

Appetite regulation (GLP-1s, dual agonists): examples include semaglutide and tirzepatide. These medications help your body to signal fullness and help reduce hunger.

Fat absorption inhibitors: such as orlistat. They work by preventing some of the fat from being absorbed during digestion.

Combination appetite suppressants (less common in the UK): such as phentermine–topiramate, which affects the brain’s appetite centres.

Injectable medications (usually once a week) such as semaglutide or tirzepatide  are weekly injections that have been proved to be clinically effective.

GLP-1 receptor agonists (e.g. semaglutide)

These medications mimic natural hormones that help regulate appetite and blood sugar. They slow digestion, increase satiety, and can lead to significant weight reduction over time.

In the UK, semaglutide is available under brand names such as Wegovy. (Educational reference only; Medicspot does not promote specific POMs.)

Dual agonists (e.g. tirzepatide)

Dual-pathway treatments act on both GLP-1 and GIP receptors, often resulting in even greater weight loss.
In the UK, tirzepatide is marketed as
Mounjaro. (Educational reference only; Medicspot does not promote specific POMs.)

Typical injection results

• Average weight reduction: up to 10–20 % of body weight after sustained use with lifestyle support for 18 months
• Administered by self-injection (subcutaneous pen) once weekly
• Common side-effects: nausea, mild stomach upset, fatigue (usually temporary)

More weight loss injection information:

• Estimate your expected results with injection treatments using the calculator below
• Watch the video below where nurse Charlene discusses how to administer a weight loss injection.

Oral treatments, such as Orlistat (Educational reference only; Medicspot does not promote specific POMs.), work by reducing fat absorption from food. They are typically used when injection therapies aren’t suitable or preferred.

These options generally result in smaller average weight loss than GLP-1 injections but remain clinically useful for some individuals.

How you feel: most people notice reduced appetite within a few weeks.

Your weight: meaningful weight loss typically builds over 3–6 months, with continued progress thereafter. Long-term success depends on sustained behaviour change and clinical follow-up.

Side-effects: mild nausea, constipation, reflux, fatigue.
These often settle as the dose is adjusted.

BMI Calculator

Medicspot Weight Loss educational videos on YouTube

Weight loss calculator tool – see below

Do I need a prescription for weight-loss medication?
Yes. All GLP-1 and dual-agonist medications are prescription-only in the UK.

How fast do results appear?
Weight typically begins to reduce within 4–6 weeks.

Can I switch medications?
Sometimes, depending on your progress and tolerance.

Are there long-term risks?
Your clinician will discuss safety and monitoring.

Is this suitable for everyone?
Not for those who are pregnant, breastfeeding, or have certain medical or mental health conditions; only for UK adults aged 18-74.

What happens if I stop the medication?
Weight regain is common if lifestyle changes aren’t maintained.

Can I use these medications if I have diabetes?
Some GLP-1 medications are licensed for both diabetes and weight management, but the dose and brand differ.

Are injections painful or difficult to use?
Most people find them simple to self-administer using a pen device.

What side-effects should I expect?
Mild nausea, constipation or fatigue are common and usually improve over time.

Can men and women use the same medications?
Yes. Both men and women respond to GLP-1 and dual-agonist medications, though results can vary based on body composition and dose.

Book a free call with our team to discuss any questions you may have about Medicspot’s weight loss medications.

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Dr Adam Abbs is a GP and Medical Lead for Europe and UK for biomarker company Hurdle. An NHS-trained GP, he graduated from Hull York Medical School in 2010 with an MBBS, then worked across a range of specialties in Newcastle and Manchester. Dr Adam Abbs is SCOPE certified (the international gold standard for obesity management) and has a keen focus on personalised medicine and weight loss. He authored Medicspot’s Behaviour Change Course.

Dr Abby Hyams completed her medical training in Bristol and has been a GP for 19 years, spending many of those as a partner in an NHS practice in Hemel Hempstead. She has a particular passion for supporting patients with weight loss and promoting positive behaviour change, helping individuals build sustainable habits that improve their long-term health and wellbeing.

This article is for general information only and should not be used for the diagnosis or treatment of medical conditions. Medic Spot Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. In the event of an emergency, please call 999 for immediate assistance.

There is no guarantee of a specific weight loss medication being prescribed. Clinicians will review your online questionnaire alongside other independently validated medical information about you and will recommend the most appropriate weight loss treatments for you based on your answers. In some cases, the clinicians may contact you for additional information. See Terms of Service for more information.