Prescription Weight Loss Pills in the UK: Overview

Prescription weight loss pills are medications that can help you lose weight, particularly if diet and exercise alone haven’t worked in the way you expected. These medications require a doctor’s prescription before you can obtain them because they contain powerful active ingredients that can cause side effects or pose certain health risks if they are used incorrectly. Therefore, they need to be carefully monitored by a doctor to make sure they are appropriate for you.

How are prescription weight loss pills different from over-the-counter pills?

Over-the-counter weight loss pills are available without a prescription and usually contain lower doses of the active ingredients, such as alli (an over-the-counter version of orlistat), or contain natural ingredients reported but typically not proven to have weight loss benefits.

The Medicines and Healthcare products Regulatory Agency (MHRA) approves all medications, including over-the-counter weight loss pills before they can be sold legally in the UK. Some over-the-counter weight loss medications are also sold as ‘food supplements’, making regulations much less strict. Whereas, prescription medication must go through many clinical trials to ensure their safety and efficacy.

Over-the-counter weight loss medications can be bought in most UK pharmacies without a prescription, but a pharmacist may still want to discuss why you want to purchase them and assess your suitability.

There are 2 main types of prescription weight loss pills available in the UK, fat absorption blockers and appetite suppressants.

Fat absorption blockers

Orlistat is a lipase inhibitor or fat absorption blocker that works by blocking the action of the enzyme, lipase, which is responsible for breaking down the fat you eat. So, instead of absorbing it, about a third of the fat you eat is passed out of your body as waste. Orlistat is available under the brand name Xenical and is taken with meals that contain fat up to a maximum of 3 times a day.

Appetite suppressants

Naltrexone and bupropion, also known as Mysimba, is an appetite suppressant that acts on the parts of the brain that control your appetite. Naltrexone influences the reward system linked to food while bupropion disrupts hunger signals, causing you to eat less. MySimba is taken daily with the dose gradually increasing over several weeks.

Weight loss pills work in different ways, depending on the active ingredients they contain.

Orlistat

Orlistat works by reducing the amount of dietary fat absorbed in your intestines by blocking the action of the enzyme responsible for breaking it down – lipase. Orlistat prevents around 33% of dietary fat from being absorbed and allows it to be passed out of the body as waste.

This results in weight loss with research showing that orlistat can help 37% of people lose at least 5% of their starting body weight in 12 weeks when combined with a low-calorie diet.

Naltrexone and bupropion

The active ingredients in MySimba, naltrexone and bupropion, work in different ways to suppress appetite and contribute to weight loss:

1. Naltrexone blocks the rewarding aspects of eating, reduces cravings, and helps you lower your calorie intake.
2. Bupropion appears to directly act on the hypothalamus, the area of the brain responsible for controlling your appetite. It may also play a role in limiting the rewarding feeling you get from eating, reducing cravings.

To get prescription weight loss pills in the UK, you must have a prescription from a doctor or registered healthcare professional. There are several ways you can obtain prescription weight loss pills in the UK:

Online services

Online doctor services, like Asda Online Doctor, can provide a private prescription for weight loss tablets like orlistat (Xenical) or MySimba following an online consultation with a doctor.

Before buying prescription weight loss tablets online, it is important that you check if the online pharmacy is registered by the General Pharmaceutical Council (GPhC) and the Care Quality Commission (CQC) to ensure they are a trusted, regulated and reputable company.

To request prescription weight loss pills from Asda Online Doctor, you need to:

1. Complete a short medical questionnaire for one of our doctors to review.
2. Select and pay for your preferred treatment.
3. If your request is approved after a doctor has checked your suitability, your treatment will be sent to your address.
4. If your order is not approved, one of our doctors will contact you via your online account to discuss alternative treatments.

To be eligible for prescription weight loss pills from Asda Online Doctor, your body mass index (BMI) must be:

• 30 or more
• 28 or more and you must have at least one weight-related condition, such as high blood pressure or type 2 diabetes

From the NHS

The NHS may be able to prescribe orlistat for individuals who meet the specific criteria.

To qualify for orlistat on the NHS, you will need to have either a BMI of:

• 30 or more
• 28 or more and other weight-related conditions, such as high blood pressure or type 2 diabetes

MySimba is not available on the NHS, instead, you will need a private prescription to obtain it.

Private clinics

Private clinics and specialist weight management services may offer weight loss pills to those who meet the specified criteria. Like online pharmacies, private clinics must be registered with the CQC and the General Medical Council (GMC).

The effectiveness of prescription weight loss pills depends on the active ingredient they contain and how well a person follows their weight loss programme.

Orlistat has been shown to help around 37% of people lose at least 5% of their body weight after 12 weeks of treatment when taken alongside a reduced-calorie diet. The studies showed that orlistat is a well-tolerated and effective weight loss treatment.

MySimba is also an effective weight loss pill which has helped people lose an average of 8.1% of their initial body weight after 56 weeks of treatment. It is most effective for people who are obese or overweight and have at least 1 weight-related health condition, like high blood pressure.

All medications can cause side effects, however, not everybody will get them. Here we look at the most common side effects of weight loss tablets and who should not take them.

Orlistat/Xenical/alli

Very common side effects include:

• headache
• stomach pain
• urgent or increased need to open your bowels
• wind (flatulence) with discharge
• oily discharge
• oily or fatty stools
• diarrhoea
• low blood sugar levels
• respiratory infections and/or flu

You should not take orlistat if you:

• are allergic to orlistat or any of the other ingredients
• have chronic malabsorption syndrome
• have cholestasis
• are breastfeeding or pregnant
• are taking the drug ciclosporin or drugs to thin your blood

Mysimba

Very common side effects include:

• feeling sick (nausea)
• being sick (vomiting)
• constipation
• headache

You should not take Mysimba if you:

• are allergic to any of the ingredients
• are pregnant or breastfeeding
• have abnormally high and uncontrolled blood pressure
• have fits (seizures)
• have a brain tumour
• are usually a heavy alcohol drinker
• have recently stopped taking sedatives or anxiety medications
• have or have had bipolar disorder
• are taking any other medications containing naltrexone or bupropion
• have or have had an eating disorder
• are currently dependent on opiates or opiate agonists or in withdrawal
• are taking medication for depression or Parkinson’s disease called monoamine oxidase inhibitors
• have severe liver disease
• have endstage kidney disease

Prescription weight loss pills are not the only weight loss treatment available. If you are looking for an over-the-counter treatment, alli is a lower dose orlistat pill which is available without a prescription.

Weight loss injections

Weight loss injections can suppress your appetite and make you feel full between meals, so you eat less, promoting weight loss. Weight loss injections, like Mounjaro, Wegovy, and liraglutide are glucagon-like peptide-1 (GLP-1) receptor agonists that bind to GLP-1 receptors and signal to the brain that you feel full.

The effectiveness of weight loss injections depends on the active ingredients they contain:

1. Mounjaro contains the active ingredient tirzepatide and can help you lose an average 22.5% of your starting body weight at the highest weekly maintenance dose of 15mg after 72 weeks.
2. Wegovy contains semaglutide and can help you lose an average 15% of your body weight after 68 weeks using the maximum weekly maintenance dose of 2.4mg.
3. Nevolat, is a daily weight loss injection that contains the active ingredient, liraglutide. Research shows it can help people lose on average 8% of their body weight after 56 weeks of treatment with the highest maintenance dose.

Lifestyle changes

Medical treatments are not the only effective weight loss strategies available. Lifestyle changes are key to an effective weight loss programme, and you’ll need to implement them even if you choose to use weight loss medications.

Some of the lifestyle changes you should consider for weight loss, include:

1. Diet – A calorie-controlled diet is important for any weight loss journey. You should prioritise foods like lean proteins, fruits, vegetables, and healthy fats over processed, sugary, and high-calorie examples.
2. Exercise – Increasing your exercise output will burn excess calories and improve your metabolism. Activities like walking, jogging, dancing, strength-based exercises, and yoga can all be beneficial.
3. Stress management – Managing stress can be useful, particularly if stress causes you to emotionally eat. So, techniques such as meditation and mindfulness can be useful for lowering your stress levels and positively impacting your weight.
4. Sleep – Poor sleep can impact your metabolism, making it more difficult to burn calories, causing weight gain. Sleep also helps to regulate the production of digestive hormones that control your appetite. It’s important to adopt good sleep hygiene and routines to promote good quality sleep.

When buying weight loss pills online it is important that you buy from regulated and trustworthy sources to make sure you’re not buying unregulated or fake products.

Some of the things you should do to ensure you make a safe purchase include:

✓ Only buying weight loss pills from online pharmacies that are registered with the General Pharmaceutical Council (GPhC).

✓ Make sure the website provides a consultation with a registered and qualified healthcare professional.

✗ Buying prescription-only weight loss medication online without a prescription is illegal. If the website doesn't give you a prescription and just allows you to buy the medication without a consultation, it is not safe.