Orlistat vs Wegovy: Key differences

Wegovy is a weight loss injection that belongs to the GLP-1 receptor agonist family of medications, which means it mimics the GLP-1 hormone. It contains the active ingredient semaglutide, which is also the active ingredient in the diabetes medication Ozempic. Wegovy works by reducing your appetite, regulating blood sugar, and keeping you feeling fuller.

Orlistat is a weight loss tablet that works by reducing how much fat you absorb from the food you eat. Orlistat is the name of the active ingredient and the medication, although you can also buy orlistat under the brand name Xenical and at a reduced, over-the-counter dose as alli or Orlos.

Both Wegovy and orlistat are used for weight loss in people who are overweight or obese.

Wegovy

Wegovy is a glucagon-like peptide 1 (GLP-1) receptor agonist, which means it tricks the body into thinking levels of the GLP-1 hormone are high.

The body responds by:

• slowing down how quickly the stomach empties
• acting on the area of the brain responsible for hunger
• improving blood sugar control

These changes mean you feel fuller for longer, making it easier to eat fewer calories and to lose weight.

Orlistat

Orlistat works by blocking a hormone in your gut called lipase. Lipase is responsible for breaking down fat from your food and helping your body absorb it.

As orlistat blocks lipase, your body absorbs less of the fat from the food you eat. This means you absorb less energy and can lose weight more easily. However, this means the tablets are only effective for foods that contain fat.

Neither Wegovy nor orlistat is a “magic” solution – both medications only work when combined with a healthy diet and regular exercise.

Wegovy is taken as a weekly injection, given under the skin (also known as subcutaneously). You will be able to give the injection yourself.

You will start with the lowest possible dose of Wegovy, 0.25mg, and will increase the dose every 4 weeks under the guidance of a healthcare professional. Some people need to increase their dose more gradually if they’re struggling with side effects.

You will continue to increase the dose until you reach the maximum dose of 2.4mg, or an alternative maintenance dose suggested by a healthcare professional.

Orlistat is taken as a tablet that’s swallowed whole with water immediately before, during, or up to 1 hour after each meal that contains fat. If a meal contains no fat, there’s no need to take a tablet.

For most people, this means taking one 120mg orlistat tablet 3 times a day.

Wegovy is suitable for people with a bodyweight of 30 or more or 27 to 29.9 if they have at least 1 weight-related health condition.

Wegovy may not be suitable for people:

• with an allergy to any of the active ingredients
• with a history of pancreatitis
• who are pregnant or breastfeeding
• taking other GLP-1 medications

Orlistat is suitable for individuals with a bodyweight of 30 or more or 28 to 29.9 if they have a weight-related health condition.

Orlistat may not be suitable for people:

• who are allergic to the active substance or any other ingredients
• with chronic malabsorption syndrome
• with reduced flow of bile through the liver and bile ducts (cholestasis)
• who are breastfeeding
• who are relying on oral contraceptives – orlistat can make them less effective, and an alternative contraceptive should be used
• who have chronic kidney failure
• who are taking medications that can interact with orlistat, such as those for HIV or epilepsy
• who are at risk of a fat-soluble vitamin deficiency – orlistat should be taken with a multivitamin containing vitamins A, D, E, and K

Both medications are effective for helping people to lose weight when taken alongside a reduced-calorie diet and regular exercise.

Studies show that 60% of people taking orlistat lost at least 5% of their body weight after 6 months, and 41% of these people went onto lose at least 10% after 12 months.

In clinical trials, 83.5% of patients taking Wegovy at the highest dose of 2.4mg lost at least 5% of their body weight by 68 weeks. In the same time period, 66.1% of patients lost at least 10% of their body weight, while 47.9% lost at least 15%.

As with any medication, Wegovy and orlistat can cause side effects, although many people take these weight loss medications without getting any.

Side effects are usually mild and can be managed at home by eating small, plain meals, staying hydrated, and taking over-the-counter painkillers if needed.

Common and very common side effects for orlistat include:

• headaches
• cold/flu-like symptoms or a chest infection
• stomach pain and discomfort
• oily spotting from the back passage
• increased farting and oily discharge when farting
• needing to open your bowels more often and suddenly
• fatty or oily stools
• diarrhoea
• pain or discomfort in the back passage
• incontinence
• bloating
• gum problems
• urinary tract infections (UTIs)
• low blood sugar (in people with diabetes)
• tiredness
• irregular periods
• anxiety

Common and very common side effects for Wegovy include:

• headaches
• tiredness
• dizziness
• altered sense of taste and/or touch
• eye problems (in patients with diabetes)
• feeling or being sick
• diarrhoea
• constipation
• stomach pain or inflammation
• acid reflux
• bloating
• burping
• farting
• gall stones
• hair loss
• injection site reactions

Serious side effects are rarer, but if you’re worried about any side effects, contact a doctor or call 999 in an emergency.

The cost of both medications varies from provider to provider. Orlistat can be purchased from Asda Online Doctor, with generic orlistat starting at £44 and branded Xenical starting at £52.

Wegovy can be purchased from Asda Online Doctor with prices starting at £88.97 for a 4-week supply of the lowest dose.

We also stock a variety of alternative weight loss medications, including Mounjaro, Mysimba, and Nevolat.

Mounjaro

Mounjaro is a weight loss injection that contains tirzepatide, which works similarly to Wegovy and also acts on the receptors for another hormone called glucose-dependent insulinotropic polypeptide (GIP). Prices start at £148.97 for a 4-week supply of Mounjaro.

Nevolat

Nevolat is a daily weight loss injection that contains another GLP-1 receptor agonist called liraglutide. Prices start at £127.

Mysimba

Mysimba is a weight loss tablet containing the active ingredients naltrexone and bupropion. It makes you feel fuller for longer, helping you to eat less and lose weight. Prices start at £99.

This table summarises the key similarities and differences between Wegovy and orlistat: