Weight Loss Injections & Tablets

Weight loss medication can work in several ways to help you lose weight, depending on the active ingredients and what effects it has in your body. They primarily work by suppressing your appetite, slowing your digestion, and keeping you feeling fuller for longer. Some also work by blocking the absorption of dietary fat or affecting your metabolism.

Weight loss injections

All weight loss injections work in a similar way, depending on which active ingredient is used (liraglutide, semaglutide, or tirzepatide).

Liraglutide is a GLP-1 (glucagon-like peptide 1) agonist. It attaches to GLP-1 receptors, mimicking the hormone. By doing this, it controls hunger levels so you eat less without feeling hungry throughout the day. It also delays the emptying of your stomach, which helps you feel fuller for longer. GLP-1 also helps to lower blood sugar levels, which can reduce cravings.

Semaglutide also works by mimicking GLP-1. This affects the parts of your brain responsible for hunger, sending a signal to your brain that you are full. It also controls blood sugar levels, helping to reduce cravings.

Tirzepatide is a GLP-1 agonist, meaning it works the same way as liraglutide and semaglutide by controlling hunger levels and cravings. It also imitates GIP (glucose-dependent insulinotropic peptide), a hormone released in the small intestine. This can improve how your body breaks down fat and sugars and is thought to enhance the effects of GLP-1.

Weight loss tablets

Weight loss tablets work in different ways to help you lose weight, depending on the active ingredient they contain.

Orlistat, Xenical, and alli contain the same active ingredient, orlistat, which is a lipase inhibitor. This blocks the absorption of up to 33% of the fat you eat at each meal. The unabsorbed fat is then excreted in waste, through your stool, helping you lose weight.

Mysimba contains the active ingredients naltrexone and bupropion, which work by acting on the area of the brain that controls your appetite. It is believed to work by suppressing hunger so that you eat less, curbing cravings, and reducing the desire to snack.

Yes, prescription weight loss medications are safe if you purchase them from reputable sources and use them exactly as they have been prescribed. Before being approved for use by health authorities, such as the Medicines and Healthcare products Regulatory Agency (MHRA), all medications, including weight loss injections, must undergo rigorous testing and extensive clinical trials.

This includes long-term trials that test both the effectiveness and safety, to determine side effects and whether certain groups of people may not be able to take it, such as due to other medications or health conditions. Even after approval, medications are still monitored closely by the MHRA and doctors for safety.

When you request any weight loss medication from Superdrug Online Doctor, our doctors will make sure it is safe for you to take.

All weight loss treatments offered by Superdrug Online Doctor will be given under the supervision of a doctor, and you can reach out to them at any time if you have any questions about your treatment, via your patient account.

Mounjaro

Mounjaro is only available privately if you meet specific criteria, such as having a BMI of 30 or above, or at least 27 and weight-related health conditions. Mounjaro was approved by the MHRA for use in the UK in November 2023 for weight loss and is now available on the NHS from certain GPs. Due to cost and availability, the NHS are focusing first on prescribing Mounjaro to those who are “most in need”.

This means those with a BMI of 40 or more, and at least 4 weight-related health conditions outlined by NHS guidelines. These guidelines will slowly change so more people can access Mounjaro, but this is expected to take a total of 12 years. You can find out more about Mounjaro on the NHS in our NHS weight loss injections guide.

➤ See our page on is Mounjaro safe for more information on studies and side effects.

Wegovy

Wegovy is a NICE-approved weight loss injection for people who are overweight or obese. The medication was approved in the UK by the Medicines and Healthcare products Regulatory Agency (MHRA) and has been available on the NHS via specialist weight management services since September 2023, if you meet the specific criteria to qualify for it.

Nevolat (liraglutide)

Liraglutide, also known as the branded injection Saxenda, was approved by NICE in 2020 for weight management. Nevolat is the generic version of Saxenda and contains the active ingredient, liraglutide. Nevolat is available both privately and on the NHS for eligible overweight and obese people.

Like all medications, weight loss injections and pills can cause side effects, although not everyone will get them. The information below shows the most common side effects for each medication.

Mounjaro:

• feeling sick (nausea)
• diarrhoea
• being sick (vomiting)
• constipation
• low blood sugar when used for the treatment of type 2 diabetes
• stomach pain

Wegovy:

• feeling sick (nausea)
• headache
• being sick (vomiting)
• diarrhoea
• constipation
• stomach pain
• weakness or tired

Liraglutide:

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

Orlistat/ Xenical/ alli:

• liquid stools
• wind with discharge
• oily or fatty stools
• oily discharge from the anus
• headache
• stomach pain/discomfort
• urgent/increased need to open your bowels
• low blood sugar when used by some people with type 2 diabetes

Mysimba:

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

What to do if you get side effects

If you get any of the common or mild side effects, they should go away on their own once your body gets used to the medication. There are things you can do to help manage the effects at home.

How to manage weight loss injection side effects

Feeling and being sick are common side effects of weight loss injections, and they can be managed by:

• eating smaller, more frequent meals that are not oily, greasy, spicy or fatty – easy-to-digest foods like soup can help
• drinking plenty of water, especially if you are sick, to help maintain your hydration
• getting plenty of rest

Another common side effect is headaches. These can usually be managed with over-the-counter painkillers, drinking plenty of water, and resting.

➤ See our pages on Mounjaro side effects and Wegovy side effects for more information. There are a number of over-the-counter options that could help ease side effects, however you should speak to a doctor about your side effects if they are not going away and are interfering with your daily life.

How to manage weight loss pill side effects

A common side effect of orlistat and Xenical is oily or fatty stools and an increased urge to use the toilet. You can help this by eating less fat and spreading it out across your 3 meals. If you are struggling with the side effects, speak to your doctor, who may suggest lowering your dose to help your body get used to the medication.

If you experience any serious side effects, such as an allergic reaction, you should call 999 or get someone to take you to A&E. If you are worried or concerned about any side effects of weight loss treatments, speak to your doctor for advice.

There are several weight loss treatments available that do not require a prescription. At Superdrug Online Doctor, we offer alli that contains the active ingredient orlistat. It works in the same way as orlistat and Xenical by reducing the amount of fat your body absorbs from meals. However, alli is available at a lower 60mg dose and is available to buy over the counter at pharmacies after a pharmacist has confirmed it is safe for you.

Other over-the-counter treatments include:

• Orlos – a branded version of orlistat that’s available without a prescription, similar to alli
• XLS-Medical Carb Blocker and Fat Binder – supplements that are marketed as appetite reducers that work to make you feel less hungry and should be used alongside a calorie-controlled diet and exercise to help reduce your calorie intake

Yes, there are some weight loss treatments available on the NHS, including Mounjaro, Wegovy, and Nevolat. New guidance means that Mounjaro is now available from certain GP practices and some other primary care services. As this is a new NHS service, those ‘most in need’ will be able to access Mounjaro first, with the rollout taking a total of 12 years.

Your GP cannot prescribe Wegovy (semaglutide) and Nevolat (liraglutide). Instead, they will need to refer you to a specialist weight management service. Whichever treatment you are prescribed, you will need to pay the current NHS prescription charge per item, unless you are entitled to free prescriptions.

Mounjaro

Mounjaro is now available on the NHS and is the first weight loss injection to be prescribed by GPs and some other primary care providers. Due to demand and NHS funding, the prescribing guidelines for Mounjaro on the NHS are currently stricter than those for other weight loss injections.

You may be eligible for Mounjaro on the NHS now if you meet both of the following:

1. Diagnosed with at least 4 out of 5 of the listed weight-related health conditions:

• obstructive sleep apnoea
• high blood pressure
• type 2 diabetes
• dyslipidaemia (abnormal levels of fat in the bloodstream), such as high cholesterol
• cardiovascular disease, such as heart disease

Currently, only these 5 health conditions are being considered for the prescription of Mounjaro on the NHS.

2. A BMI of 40+.

These guidelines will slowly be adjusted to allow more people to get Mounjaro, still focusing on those most at risk of weight-related health complications.

From June 2026, you may be eligible if you have:

• 4 or more of the listed health conditions
• a BMI of 35 or more

From March 2027, you may also be eligible if you have:

• 3 of the listed health conditions
• a BMI of 40 or more

For people from certain ethnic backgrounds, such as Asian, Chinese, Middle Eastern, Black African or African-Caribbean, the qualifying BMIs are 2.5 lower.

Wegovy

Wegovy is available on the NHS if you have weight-related health issues and a BMI of either:

• 35 or more, or 32.5 or more if you are of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin
• 30 to 34.9, or 27.5 to 32.4 if you are of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin, and you meet any further criteria needed to be treated by a specialist weight management service

Liraglutide

Liraglutide and Saxenda are suitable for adults aged up to 75 and can only be prescribed if the following apply:

• a BMI of at least 35, or 32.5 or more if you’re of Asian, Chinese, Middle Eastern, Black African or African-Caribbean origin
• you have non-diabetic high blood sugar (hyperglycaemia)
• you’re at high risk of heart problems such as heart attacks and strokes

Orlistat

Orlistat and its branded alternative, Xenical, are available on the NHS if you have already made a significant effort to lose weight by changing your lifestyle and if you have a BMI of:

• 28 or more and at least 1 weight-related condition, such as high blood pressure or type 2 diabetes
• 30 or more

To qualify for prescription weight loss treatment, you need to have a BMI of over 30, or over 27 or 28 with certain other medical problems, but this depends on the medication.

Certain medical conditions or medications could interact with prescription weight loss treatment, making it less effective or unsafe. You should always speak to a doctor before taking weight loss treatment, and always be honest and accurate. This is because weight loss medication could cause serious illness and severe side effects if it is not suitable for you.

Contraindications

You should speak to a doctor before taking any weight loss medication, especially if you have:

• liver or kidney problems
• IBD (inflammatory bowel disease)
• thyroid disease
• problems with your heart
• epilepsy or a history of seizures
• anxiety or another mental health condition
• problems absorbing nutrients, which is called chronic malabsorption syndrome

Weight loss treatment is not suitable for anyone:

• under 18
• breastfeeding or pregnant
• with allergies to any ingredients in the medication

Medication that can interact with weight loss treatment

Some medications can interact with weight loss treatment, making it not work as it should. This could be unsafe. Speak to your doctor if you take any other medications, especially:

• epilepsy medication
• treatment for HIV
• mental health treatment
• heart medication, such as amiodarone
• blood thinners, like warfarin
• hypothyroidism treatment, such as iodine salts
• diabetic treatment
• Parkinson’s disease medication, especially monoamine oxidase inhibitors
• opiates
• steroids
• malaria treatment
• treatment for infections, such as antibiotics
• asthma treatment, such as theophylline

Weight loss treatments can be an effective tool to help you lose weight, but you should still exercise regularly and eat a healthy and balanced diet.

Exercise

Exercise can help with weight loss as you burn calories by being active. When you eat food, energy is stored in your body as fat. If you eat more food than the energy you expend, you will gain weight. Your body needs physical activity to burn the energy from your food. It can also help to prevent and manage some medical conditions, like diabetes. This will help you lose weight and maintain a healthy weight.

According to the NHS, you should do around 150 minutes of moderate intensity exercise every week. This could include things like:

• dancing
• cycling
• power walking
• hiking

You can also do 75 minutes of higher-intensity exercise, like running and circuit training. The best way to use exercise for weight loss is by combining moderate and high-intensity exercise.

You should also work on your balance and strength at least twice a week. This could involve using weights or doing activities like tai chi and yoga.

Superdrug Online Doctor provides advice on exercising to lose weight as part of the weight loss guide included in our service.

Diet

Your diet is very important when trying to lose weight. The NHS advises reducing your calorie intake by 600 calories every day, which is known as a calorie deficit. For women, this means having no more than 1,400 calories a day or 1,900 calories for men.

To achieve a healthy and balanced diet, you should increase the amount of healthy foods you eat. This includes:

• plenty of fruits and vegetables
• lean protein sources like white meat, fish, and eggs
• whole grain foods, like rice and potatoes
• healthy fats, like avocado
• nuts
• beans
• some dairy foods, like natural yoghurt

There are also some foods you should avoid or limit when trying to lose weight, such as:

• sugary food and drinks, like sweets and chocolate
• high-fat foods, especially those containing saturated fat
• oily or fried foods
• crisps
• white bread
• alcohol