Metformin and weight loss: What you need to know

Metformin is a prescription-only medication, belonging to a class of drugs known as biguanides, they are used to treat and prevent type 2 diabetes.

Insulin is an important hormone as it helps your body to use sugar for energy. However, when there is not enough insulin to use, or your body cannot use the available insulin effectively, your blood sugar levels rise. Metformin is used to help your body regulate and use insulin more efficiently to lower your blood sugar levels and also decrease how much sugar your body absorbs from the food you eat.

Metformin is usually taken as an oral tablet. The dosage of the tablet and the schedule will depend on what your doctor thinks is best for you. You will usually start on a lower dose and work your way up.

Yes, metformin can help with weight loss, but you are not likely to see a significant amount of weight loss when using metformin on its own. Several smaller studies have shown a loss of between 1.5 to 8.4lbs in patients, but there has not been enough clinical evidence for metformin to be considered as a weight loss treatment currently.

The largest study to show the weight benefits of metformin is the Diabetes Prevention Study (DPP). In this study, patients had a 2.1kg loss on average, with weight loss continuing over the next 10 years in patients who followed their medication schedule properly.

People with severe insulin resistance are more likely to experience a significant loss of weight as a result of taking metformin, and overall weight loss was independent of age, sex, and body mass index (BMI). As poor insulin control can be linked to weight gain, using metformin to better handle your insulin and blood sugar levels could help you lose weight.

Metformin can also affect your appetite regulatory centers in the brain, which can make you feel fuller and less hungry, so it may become easier for you to eat fewer calories.

While metformin can help you lose some weight, there are other pills that are clinically proven to help patients with weight loss that are much better alternatives if you’re looking to primarily lose weight.

Yes, however, while metformin can help in weight loss, it is not licensed for that purpose in the UK. Other weight loss treatments, like weight loss injections, will often lead to more weight loss than metformin.

Here, we look at the difference in weight loss between metformin and licensed weight loss medications currently available in the UK:

If you do get metformin prescribed for weight loss, this will be an ‘off-license’ prescription. This means the doctor is prescribing a medication for a condition they believe the medication can still help with, but it is not what the manufacturer has licensed the medication for.

Can you buy metformin for weight loss in the UK?

No, you cannot buy metformin for weight loss in the UK as it is a drug used primarily to treat diabetes. Some private services may offer metformin as an off-license prescription for weight loss, though this is not likely with the number of options available for licensed weight loss medications. If you have diabetes, your doctor or diabetes specialist may prescribe metformin for blood sugar control and weight loss, but not only for weight loss.

Asda Online Doctor does not prescribe metformin for weight loss, but we have other approved weight loss treatments available.

Common side effects of metformin, that affect 1 in 100 people, include:

• nausea or vomiting
• stomach ache
• diarrhoea
• loss of appetite
• metallic taste in the mouth

A vitamin B12 deficiency can also be a common side effect of metformin and can lead to anaemia, especially in people taking higher doses. This can lead to:

• feeling very tired
• muscle weakness
• mouth ulcers
• a sore, red tongue
• pale or yellow skin
• vision problems

Your doctor may prescribe a B12 supplement if your levels get too low.

In rare cases (1 in 10,000), you may experience a serious side effect and should speak to your doctor, call 111, or 999 in an emergency if:

• you feel generally unwell, including:
• breathing fast or shallow
• feeling very tiredc
• experiencing shivers or feeling very cold
• noticing your heartbeat is slower than usual
• the whites of your eyes or skin turn yellow

If you are looking for a weight loss treatment that is not metformin, there are many other options available.

Weight loss injections

Weight loss injections are available in the form of daily or weekly injections, they should be taken alongside an exercise and nutrition plan.

Mounjaro

This is a prescription-only weight loss injection that contains tirzepatide. It works by making you feel fuller for longer and helps to decrease your appetite.

Wegovy

This contains the active ingredient semaglutide, which helps you feel fuller for longer by mimicking a hormone that is naturally released when you eat. It is a weekly weight loss injection, similar to Mounjaro.

Nevolat

This contains the active ingredient liraglutide, which works by making you feel fuller for longer and reducing your appetite, like Wegovy and Mounjaro. It is an injectable medication, but is injected once daily instead of once weekly.

Weight loss pills

Weight loss pills may be a suitable option for you if you cannot or are not sure about taking weight loss injections. They work in a slightly different way to weight loss injections, but can also be effective. There are a range of options available at Asda Online Doctor, including:

Wegovy pill

A prescription-only GLP-1 (glucagon-like peptide-1 receptor agonist) tablet. It is taken once daily in the morning 30 minutes before food. Similar to the injection form, it works by mimicking natural hormones to suppress your appetite by making you feel fuller for longer.

Orlistat

A prescription-only weight loss tablet taken 3 times a day with a meal that contains fat. It works by reducing the amount of fat that is absorbed when you digest it.

alli

An over-the-counter weight loss tablet containing 60mg of orlistat. It works by stopping around 25% of the fat you eat being absorbed.

Xenical

This is a branded version of orlistat generic tablets, which contains 120mg of orlistat, and works by reducing the amount of fat your body absorbs. One pill is taken with meals containing fat, up to 3 times a day.