In short

  • Orlistat is a weight loss pill that helps encourage weight loss by reducing the amount of fat you digest from your diet.
  • Orlistat is a lipase inhibitor, which means it works by blocking the lipase enzyme located in your intestine lining from digesting fats present in the food you eat.
  • Orlistat comes as an oral capsule.

Last Updated: 25/06/2025

Orlistat is a weight loss pill that helps encourage weight loss by reducing the amount of fat you digest from your diet. 

Orlistat is a lipase inhibitor, which means it works by blocking the lipase enzyme located in your intestine lining from digesting fats present in the food you eat. The naturally occurring lipase enzyme in our body works by breaking down the fats we eat into smaller, digestible forms. By blocking the action of lipase, it prevents ⅓ of the fat you consume in the meals from being digested, reducing the calories absorbed by the body. As for the undigested fats in the body, they are removed via faeces. 

Orlistat comes as an oral capsule. The daily dosage of Orlistat recommended by healthcare professionals is 120 mg. You take Orlistat 3 times a day with meals that contain fat. In the case where you miss a meal or have a meal with no fat, or contains less than 15 grams of fat, it is recommended not to take Orlistat as it can lead to unpleasant side effects. 

Common side effects can include:

  • Greasy oily stools 
  • Flatulence
  • Oily spotting on your underwear 

These side effects can be reduced by eating a low-fat balanced diet. 

How Effective is Orlistat, and How Long Does it Take to Work?

Orlistat is an effective weight loss medication when it is coupled with a reduced calorie diet and exercise. Orlistat has been shown not to have significant weight loss effects when taken alone. By reducing fat intake and regularly exercising, you will start to notice weight loss effects. 

Orlistat is generally used for around 3 months for optimal body weight loss. If a weight loss of 5% is not noticed after those 3 months, the treatment time can be prolonged. A 6-month dose-ranging study group clinical trial found that Orlistat reduced the weight of patients taking 120 mg three times a day for 6 months by 39% (with a low calorie diet).

Orlistat starts working right away once taken; it binds to the fat in your food from the very first dose. However, this does not mean you will lose weight straight away. With reduced dietary fat and regular exercise, you will notice a gradual but sustained weight loss with Orlistat. If you cut down your calorie intake by 500 calories per day, you will notice about 1 lb of weight loss per week. This is deemed as a healthy weight loss goal.

Do not be disheartened – weight loss should be slow and maintained, as sudden weight loss is not healthy for the body. 

Are There Alternatives to Orlistat?

At Simple Online Pharmacy, we stock a wide range of weight loss treatments, including Saxenda. Rather than a pill, Saxenda is taken as a daily injection. Instead of preventing fat from being digested, Saxenda uses your body’s hormonal systems to make you feel fuller, even when you  eat less food. This, combined with a calorie-controlled diet and exercise, means you can lose weight. You can learn more about Saxenda in our blog post “Saxenda – Unboxing Your First Order“.

We also stock branded variations of Orlistat, including Xenical and Alli. These medications are chemically identical to Orlistat – the only difference may be in dosage and branding. You can read further about the differences between these medication in our blog post “Xenical, Alli and Orlistat – The Differences”.

How to Get Orlistat?

You cannot purchase Orlistat over the counter without a prescription from a doctor. When you buy Orlistat from Simple Online Pharmacy, we will ask you to complete an online assessment with us which will be reviewed by one of our doctors before we prescribe it to you. If there are no concerns (including heart disease or high blood pressure), they can prescribe Orlistat, and we can post it straight to your doorstep. 

Sources

References

2 sources were selected to match the subject of this article. Link destinations were checked twice when added. This does not mean every statement has been individually source-mapped or clinically approved.

  1. Xenical 120 mg hard capsules: Summary of Product Characteristics

    Neon Healthcare via electronic medicines compendium · HTML · regulator-approved product information · Current emc SmPC · Link destination checked 5 September 2026

  2. Orlistat: a medicine to treat obesity

    NHS · HTML · medicine patient guidance · NHS Medicines A to Z · Link destination checked 5 September 2026

Reference links open the cited source pages. If you spot something out of date, tell our content team.

Who wrote this

Written and reviewed by our team

Authored by

Tyson Wilkman - Clinical Pharmacist

Pharmacist / Content Writer

AHPRA Registration PHA0002235589

Tyson started with Simple Online Pharmacy in 2021. He was responsible for helping review and author accurate site content. He worked with our GPs to make sure all aspects of the medicines are covered. Since working with Simple Online Pharmacy, Tyson has moved to a new position with Simple Online Doctor.

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Medically reviewed by

Karim Nassar, Co-Founder, Pharmacist & Author

Karim Nassar

Co-Founder, Pharmacist & Author

Karim is a registered pharmacist with the General Pharmaceutical Council (GPhC) and was a founding member of Simple Online Healthcare in 2015. With a Master of Pharmacy degree from Strathclyde University, Karim brings a strong foundation in pharmaceutical care and a passion for leveraging digital solutions to improve patient access to healthcare.

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