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Orlistat Review By Expert: How Much Is effective For Weight Loss?

orlistat weight loss

As many of us are aware, losing weight can be difficult. Dietary fat intake (‘bad fat’) can significantly increase calorie intake and contribute to overall obesity.

Orlistat is one of two drugs available in the UK for the management of obesity. Orlistat stops the absorption of fats in the body, causing weight loss.

Orlistat is a medication belonging to the drug class known as ‘Peripherally acting antiobesity agents’. Orlistat is a drug used for weight loss and to reduce the risk of regaining weight that was already lost. When incorporated with a calorie-deficit diet and exercise, Orlistat can show the best results. This medication is generally taken orally. In 1999, Orlistat was approved by the FDA for prescription use and later in 2007 for over-the-counter. This medication should be used by adults only. You must be 18 years or older to use this medication.

Orlistat (P) And Orlistat (POM) What Is The Difference?

Orlistat has been available on the market since 1999 as a prescription-only medication. As with many drugs, initially, Orlistat was only available as one branded product called Xenical (120mg of Orlistat) until the expiry of ‘exclusivity’ rights (patent) in 2009. Today Orlistat is available as a generic medication produced by a number of drug companies.

In 2009 Orlistat became available as pharmacy-only medicine (P), known as Alli for sale to the public, without a prescription. Alli can be purchased from a chemist under the supervision of a pharmacist or online from registered pharmacies.

Each capsule of over-the-counter Alli contains 60mg of Orlistat. In contrast, each capsule of prescription-only Orlistat contains 120mg of Orlistat. Both Alli and Orlistat (POM) are indicated for the treatment of obesity in conjunction with a mild-low calorie and fat diet.

Quick FAQ

Is Xenical the same as orlistat?
The difference between orlistat and Xenical is that orlistat is a generic form of the drug, whereas Xenical is a branded version.

Who Can Buy Alli (Orlistat)?

Who Can Buy Alli (Orlistat)

Over-the-counter Alli can be used by adults (18 years or over) who are overweight with a body mass index (BMI) of 28 kg/m2.

Although there is no specific direction to measure a patient's BMI when a purchase request is made at the conventional pharmacy.

Customers may be asked to check their BMI (weight and height measurement).

Online pharmacies have a more relaxed approach to the sale of Alli.

When purchasing Alli online, customers may need to read and agree with a disclaimer confirming the suitability of the drug or answer pre-sale questions; for example, you may be asked to provide your weight and high (to calculate BMI) detail any other conditions you may have.

Orlistat Review Of Mechanism Of Action

Orlistat stops the production of certain substances in the body, responsible for breaking down fats in the intestine. As a result, these fats are not absorbed by the body and are removed mainly through feces. It is estimated that Orlistat blocks the absorption of about 25% of fat that is being consumed.

How To Take Orlistat?

  • Alli: one 60mg capsule is taken three times a day which each meal contains fat. No more than three capsules should be taken in 24 hours.
  • Orlistat: one 120mg capsule is taken three times a day, also with a meal that contains fat

How To Take Orlistat?

Orlistat should be taken just before, during, or up to one hour after a meal. Orlistat should not be taken when a meal is missed or contains fat.

Patients are recommended to take a multivitamin containing fat-soluble vitamins (A, D, E, and K) at night before going to bed.

Quick FAQ

How fast does orlistat start working?
In 1-3 months, you should see effects.

Can You Get Orlistat On NHS?

A GP can prescribe orlistat. Last year (Oct’ 18—Sep ’19), almost 360000 prescriptions were issued for Orlistat (OpenPrescribing.net, 2019).

Can You Get Orlistat On NHS?

Prescription-only Orlistat is indicated for the management of obese patients with a body mass index (BMI) greater or equal to 30 and where diet and exercise have been evaluated or overweight patients with BMI greater of or equal to 28 with existing risk factors

Such (NICE, 2017):

  • As type 2 diabetes,
  • High blood pressure
  • High cholesterol /fats level

Orlistat will be re-prescribed only if 5% or more of body weight loss is achieved within 12 weeks of the start of treatment; however, different goals may be set for certain patients, for example, type 2 diabetic patients (ibid).

Orlistat Dosage

Usual Adult dose for Obesity

Xenical: 3 doses of 120 mg orally with each meal that contains fat.
Alli: 3 doses of 60 mg with each meal that has fat.

Usual pediatric dose for Obesity(12 years and older)
Xenical: 3 doses of 120 mg orally with each meal that contains fat.
Alli: Alli OTC is not recommended for pediatric use.

Tips To Start Orlistat

Here are some tips to start reducing weight when on Orlistat:

  • Reducing your fat intake to 30% of your total calories is advised while taking Orlistat
  • Take Orlistat after a meal that includes fat
  • Try to choose low-fat dairy products and food in general
  • Follow the proper dosages as prescribed by your doctor

Orlistat Foods To Avoid

The idea is simple: avoid fats. There are thousands (if not millions) of websites, blogs, useful books, diet plans, and recipes that focus on healthy eating. Follow a low-fat, reduced-calorie diet.

Some ideas for a low-fat diet:

Orlistat Foods To Avoid

  • Aim for meals with fat-derived calories of around 30% (15 grams of fat) per meal
  • Reduce/avoid the use of oils in cooking
  • Use low-fat spreads instead of butter
  • Focus on eating ‘low-fat range’ of products, for example, low-fat cheese, light or fat-free cream cheese, low fat/fat-free yogurts, and so on
  • Avoid ‘take outs’ and deep-fried foods like chips
  • Eat lean cuts of skin free meat

Pros And Cons Of Orlistat


  • The unabsorbed fat is flushed out from the body via stool. It helps to prevent the extra unabsorbed fat from staying in your system.
  • Orlistat is readily available at pharmacies as a prescription medicine and over-the-counter medicine.
  • Orlistat works by blocking the consumed fats from being absorbed by the body
  • Reduced risk of regaining the lost weight
  • Easily available OTC drug
  • Weight loss


  • Orlistat absorbs some fat-soluble vitamins and beta carotene along with fats. Hair loss is commonly associated with people who lack
  • Vitamin D. It is advised to include multivitamins in foods and supplements to balance out the adverse effects caused by Orlistat.
  • Orlistat use may cause oxalate kidney stones or oxalate nephropathy. Oxalate nephropathy is often asymptomatic and keeps on aggravating with the help of Orlistat.
  • Some people may face pale stools as a side effect due to Orlistat. It can also cause dark urine, fatigue, nausea, and pale stools, signs of a liver problem.
  • Liver issues
  • Hair loss
  • Kidney issues

Orlistat Ingredients

Orlistat is the active ingredient used in medicine brands. Other ingredients include:

  • Microcrystalline cellulose
  • Sodium starch glycolate
  • Povidone
  • Sodium laurilsulfate
  • Talc

Advantages Of Using Orlistat

The primary advantage of using Orlistat is weight loss. People who are having difficulty reducing weight can benefit from the medicine. This medication is beneficial for people who are obese (people with BMI 30 or higher). It is also helpful for overweight people (BMI of 27 or higher).

People suffering from heart conditions due to a few extra kilos, such as high blood pressure or heart diseases, can benefit from Orlistat. It also has an excellent mental effect. People can get motivated and feel good about themselves when they see bodily changes positively. People gain confidence in themselves, leading to their success and happiness in life.

Orlistat Review

Alli and Xenical are the two brands sold under Orlistat medicine. Alli is available at the strength of 60 mg while Xenical is available at the strength of 120 mg capsules. Orlistat works by blocking the enzymes in the gut that digest fat. Orlistat blocks approximately one-third of the fat that we consume. Hence, it is an effective medication to lose weight. Orlistat medications are widely available at local pharmacies and at online pharmacies without prescriptions.

Orlistat Review Of Clinical Effectiveness: Can You Lose Weight With Orlistat?

Orlistat was well studied in human trials. The next couple of paragraphs summarises the primary outcome of clinical trials for Orlistat and Alli, focusing on the effectiveness of weight loss (EMA, 2009 & EMA, 2008).

Xenical studies (Orlistat 120mg taken three times a day)

  • Seven main studies, which included over 3000 obese patients
  • Duration: one to four years
  • Placebo-controlled: some patients were given a ‘dummy’ pill
  • Xenical (120mg) or placebo were given three times a day to patients in conjunction with dieting (hypocaloric, low-fat diet)
  • Results: After one year, patients on Xenical lost an average of 6.1kg of body weight compared to 2.6kg who took a dummy pill
  • 20% of patients who took Orlistat lost more than 10% of their body weight as compared to 8% of patients who took a dummy pill
  • At the end of the four-year study, 21% of patients lost over 10% of body weight as compared to 10% of patients who took a placebo

Alli studies (60mg of Orlistat)

  • Two main studies
  • Duration: 12 months
  • Placebo-controlled: Orlistat 60mg three times a day or placebo pill were taken by participants alongside hypocaloric, low-fat diet
  • Most weight losses occurred during the first six months of the trial
  • At six months, average weight loss with Alli was 5.20kg compared to 3.1kg with placebo (study 1) and 3.6kg versus 1kg (study 2) with an overall average weight loss of 4.4kg when Alli was taken compared to 2.1kg when a dummy pill was taken (both studies)
  • At 6 months, over 16% of participants lost 10% or more of their body weight as compared to 6.5% for placebo

Interestingly, the data from the above studies showed improvements in cholesterol levels which decreased after 6 months of treatment:

  • Total cholesterol decreased by 2.4%
  • LDL ‘bad’ cholesterol decreased by 3.5%
  • Patients taking a placebo experienced an increase in cholesterol level

Alli also positively affected waist circumstance, which decreased after six months. Overall, both Orlistat 120mg and Alli (60mg of Orlistat) showed a significant reduction in body weight as compared to the placebo.

Quick FAQ

What is the strongest weight loss pill?
The most successful weight loss medicine currently available is phentermine-topiramate extended-release (Qsymia).

What Do Customers Think About Orlistat?

“I’ve been using Orlistat for about two months. I’ve lost 20 pounds and can wear smaller dresses. I’ve been eating healthy apart from little treats during weekends. It has been a miracle journey for me since using Orlistat. I highly recommend using this drug.” -Natasha.

“I went to see my doctor last August and asked for help with my weight. I was depressed as it bothered me. He gave me Orlistat to use, and no five months, I’ve lost 14 kgs. It might probably be the best decision of my life.” -Peter.

“Started using this medicine a month ago. Now in my 4th week and looking forward to losing more weight. Already lost 12 pounds, and it’s been amazing.” -Erica.

How Does Orlistat Work?

Orlistat boosts the weight loss process by reducing the amount of dietary fat absorbed in your intestines. Lipase is found in the digestive tract; it helps the body break down dietary fat into minor compounds stored for energy. Orlistat is used to enhance lipase. About 25% of the consumed fat in your meal isn’t broken down and eliminated through stools. For the results, you have to wait for 1 to 3 months. You can expect to lose 5% of your starting body weight in 3 months. If you don’t see any results, the doctor might stop the treatment and recommend something else that might suit you.

Orlistat Review Of Drug Interactions

Please refer to the product information leaflet for a full explanation of the possible interactions of Orlistat.

The following drug interactions are listed in Orlistat’s specifications:

  • Amiodarone (used in the treatment of ventricular fibrillation): in a healthy volunteer, some decrease of levels of amiodarone was observed
  • Ciclosporin (immunosuppressive medication): it is not recommended to use Orlistat whilst on ciclosporin as plasma levels of ciclosporin may be affected
  • Acarbose (used in treatment in alcohol dependence): concomitant use should be avoided
  • Oral anticoagulants (for example, warfarin): use of Alli together whilst on anticoagulants are contraindicated, however when prescribed, Orlistat can be considered, providing an international normalized ratio (INR) is monitored
  • Fat-soluble vitamins (A, D, E, K): the majority of patients taking Orlistat during a four-year study had no change in levels of vitamins A, D, E, and K; however, manufacturers of Orlistat recommend taking a multivitamin supplement at bedtime
  • Possible interaction with antiretroviral medicinal products for HIV

Orlistat interaction with oral contraceptives:

There is no direct interaction between Orlistat and oral contraceptive drugs; however, Orlistat manufacturers recommend using additional contraceptives if patients experience severe diarrhea.

In 2010, MHRA issued a safety update in relation to possible interactions with Orlistat:

  • Levothyroxine:
  • Decreased absorption of iodine salts or levothyroxine (or both) may cause reduced control of hypothyroidism or cause (rarely) hypothyroidism
  • Patients are advised to speak to their doctor before taking Orlistat
  • Antiepileptic drugs:
  • Orlistat may affect the absorption of antiepileptic medication such as lamotrigine or sodium valproate, causing a lack of seizure control

Always read the product information leaflet before starting any treatment or speak to your GP or pharmacist.

Orlistat Side Effects

Some common side effects caused due to Orlistat are:

  • Oily or fatty stools-(Due to fat not being absorbed when using Orlistat, you might experience oily or fatty stools)
  • Gas discharge
  • Stomach pain-(Orlistat blocks intestinal fat absorption by preventing gastric and pancreatic lipase that causes stomach issues including stomach pain)
  • Nausea-(Orlistat blocks intestinal fat absorption by preventing gastric and pancreatic lipase that causes stomach issues including nausea)
  • Loose stools

Some adverse side effects caused by Orlistat are:

  • Lower back pain
  • Blood in the urine-(Users have reported bleeding from the rectum which causes blood in the urine)
  • Signs of Kidney problems-(Orlistat may cause oxalate kidney stones leading to chronic kidney disease even after stopping the medicine)
  • Signs of Liver problems-(Itching, yellow skin, loss of appetite, or dark urine are all signs of liver problems and immediately must be consulted with your healthcare professional)

Not all side effects are included in this article. It is always better to seek professional help if you have any symptoms or side effects after using Orlistat.

Quick FAQ

What happens if you take Orlistat on an empty stomach?
If you miss a meal or do not contain fats, taking Orlistat is unnecessary. It can lead to side effects such as wind, loose stools, and even liver damage.
What foods should you avoid when taking Orlistat?
Foods that have more calories and fat should be avoided. It’s better to choose lean fat and low-fat dairy products.
Do you smell foul when taking Orlistat?
If you consume fat under the medication, oily stools and unpleasant odor can occur.

Is Orlistat Worth It?

We think using Orlistat is worth it if you plan to lose weight. Doctors widely suggest it for weight loss, and it is relatively safe to use. It is readily available as an over-the-counter drug or by prescription. You should follow proper guidelines as suggested by your doctor for lowering the risks of the side effects.

Orlistat promotions and discounts

Orlistat Alternative Drugs

At this time in the UK, there are only two drugs licensed for weight loss, the first of which is Orlistat. Second, Liraglutide, known under its branded name as Saxenda. Saxenda works in a different way from Orlistat. Read more about Saxanda in my separate post: Saxenda review – effectiveness of NEW weight loss drug.


Orlistat is an effective weight loss pill with minimal side effects. When incorporated with a calorie-deficit diet and regular exercise, Orlistat can show the best results. We advise you to have multivitamins when using Orlistat. It has widely used by people all over the world. You can purchase it by prescription or over-the-counter.