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Orlistat weight loss tablets

Orlistat is a fat-blocking weight-loss tablet, available over the counter as Alli or on prescription as Xenical. It is one of the longest-established weight-loss medications in the UK, and a gentler, non-injection alternative to the newer GLP-1 medications.

How orlistat works

Orlistat is a lipase inhibitor. Lipases are the gut enzymes that break down the fat in your food so the body can absorb it. Orlistat blocks them, so some of that fat passes straight through rather than being digested and stored, which means fewer calories absorbed from fat.

Unlike the GLP-1 medications, it does not touch your appetite. It works in the gut rather than the brain, so you will not feel less hungry on it.

How you take it

Orlistat comes in two strengths under two names: Alli, the lower 60 mg dose available over the counter, and Xenical, the higher 120 mg dose available on prescription and also sold as unbranded generic orlistat.

Both are capsules taken with meals that contain fat. A doctor or pharmacist talks you through the right routine before you start.

Results to expect

Orlistat gives a steadier, more modest result than the injections. Alongside changes to diet and lifestyle, people lose around 4% of their body weight after three months and around 8% after a year. For comparison, the GLP-1 medications reach 10 to 20% over a year.

The medication does the fat-blocking, but the weight loss only sticks when the eating and lifestyle habits change with it.

Side effects and tolerability

Orlistat is generally well-tolerated, and fewer than one in ten people stop because of side effects. Most are digestive and tied to how much fat is in a meal, so the more fat you eat, the more noticeable they are. Eating less fat usually keeps them in check.

A doctor or pharmacist checks it is suitable for you before you start.

Who it is for

Orlistat is usually considered for adults with a BMI of 28 or above who also have a weight-related condition, or a BMI of 30 or above, when a doctor or pharmacist agrees it is right for you. It is not usually recommended during pregnancy or breastfeeding.

It tends to suit people who want a gentler option, or who would rather not use, or cannot take, an injection.

What you get with Second Nature

Orlistat blocks some of the fat you eat, but it does not change why you reach for certain foods or build the habits that keep weight off. That is what Second Nature focuses on.

Your plan is a structured programme around your eating, behaviour and lifestyle, with a registered dietitian and daily coaching in the app, built to help the weight stay off for good.

Frequently asked questions

How does orlistat help with weight loss?

It is a lipase inhibitor, which blocks the gut enzymes that digest fat, so some of the fat you eat passes through rather than being absorbed. It does not reduce your appetite.

What is the difference between Alli and Xenical?

They are the same medicine at different strengths. Alli is the lower 60 mg dose available over the counter, and Xenical is the higher 120 mg dose available on prescription, also sold as generic orlistat.

How much weight can I lose on orlistat?

Alongside diet and lifestyle changes, people lose around 4% of their body weight after three months and around 8% after a year, which is more modest than the GLP-1 injections.

Can I get orlistat on the NHS?

Yes, if you meet the criteria, usually a BMI of 28 or above with a weight-related condition, or 30 or above. It is also available over the counter as Alli or through a private prescription.

What are the side effects of orlistat?

It is generally well-tolerated, with fewer than one in ten people stopping because of side effects. Most are digestive and depend on how much fat is in your meals.

Is orlistat better than Wegovy or Mounjaro?

It depends on what you want. The GLP-1 medications deliver more weight loss (around 15 to 20% a year versus 4 to 8% for orlistat), but cause side effects in more people. Orlistat suits people wanting a gentler, non-injection option.

Can I take orlistat if I am pregnant or breastfeeding?

No, orlistat is not usually recommended during pregnancy or breastfeeding. Speak to your GP or pharmacist about suitable options.

Sources

Orlistat weight loss (around 4% at three months, around 8% at a year): Second Nature published guides.

Comparison with GLP-1 medications (around 15 to 20% a year versus 4 to 8% for orlistat): Second Nature published guides.

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FAQs

What is weight loss medication?
Weight-loss medications like Mounjaro (tirzepatide) and Wegovy (semaglutide) are prescription treatments that help regulate appetite and support long-term weight loss.

They work by targeting the same hormones your body uses to manage hunger, fullness, and blood sugar, making it easier to eat less, feel satisfied sooner, and build healthier habits.
What is the difference between Wegovy, Mounjaro, and Orlistat?
Wegovy (semaglutide) and Mounjaro (tirzepatide) are both once-weekly injections that help most people to lose weight. However, they have different active ingredients. In Wegovy, the active ingredient is semaglutide and in Mounjaro the active ingredient is tirzepatide. Orlistat, unlike Wegovy and Mounjaro, comes in the form of a pill that is taken up to three times a day, every day. Wegovy is used solely for weight loss and works by mimicking a single hormonal receptor (GLP-1) which slows down gastric emptying, making you feel fuller for longer. Mounjaro activates both the GLP-1 receptor as well as the GIP receptor, which promotes energy storage. Mounjaro is used for both weight loss and for managing type 2 diabetes. Both GIP and GLP-1 receptors are expressed in the areas of the brain important for appetite regulation. Orlistat works in the stomach and intestines by blocking the enzymes (lipases) that break down dietary fats. This in turns prevents a percentage of the fats you've eaten (approximately one-third) from being absorbed into the body. Instead, this undigested fat is excreted with your stools. This ultimately creates a calorie deficit that aids in weight loss. Because Wegovy and Mounjaro are different medications, this also means that their starting, escalation doses and maintenance are different. They also have different manufacturers: Wegovy is made by Novo Nordisk, whilst Mounjaro is made by Eli Lilly. Orlistat is available in the UK in two different dose strengths depending on patient eligibility: a 60mg Pharmacy Medication and a 120mg Prescription Only Medication. However, there is no escalation process; patients start and maintain on the same dose for the duration of their treatment. This service only offers the 60mg dose of Orlistat, which is made by Haleon UK Trading Limited.

If you want a deeper breakdown, read our Wegovy vs Mounjaro comparison guide.
Is it safe?
Yes, when prescribed responsibly and monitored by a qualified clinician.

GLP-1 medications are well-studied, with strong safety records from long-term clinical trials.

However, like all medications, they aren't suitable for everyone. That's why we complete a detailed health assessment before prescribing.
Is the medication safe with my existing conditions (HRT, thyroid issues, previous gallbladder removal)?
We can't give you a yes or no without completing our health assessment; the clinical prescribing clinician will evaluate your individual situation.

Previous gallbladder removal, certain thyroid conditions, and other health issues require careful consideration but in many circumstances, you can take Mounjaro alongside these conditions. HRT typically isn't a problem.

The onboarding includes a detailed health questionnaire and clinical review. Be completely honest about your health history.
What happens when I stop taking the medication? Will I regain weight?
It depends on the habits you've built while on medication. Research shows people typically regain two-thirds of lost weight without proper support.

Our data suggests something different: participants who develop sustainable habits with our programme show only 3.2% weight regain after stopping, compared to 6%+ without support.

We focus on building these habits from day one; when appetite is lower and it's easier to learn what healthy eating actually looks and feels like.

The medication gives you a window to change your relationship with food, not just lose weight temporarily.
What support do I get from my health coach? How do I communicate with them?
Your health coach is a UK-registered dietitian or nutritionist, available 5 days a week through the app. You message them directly and get responses typically same day.

They help with managing side effects, adjusting eating habits as your appetite changes, and building practical skills around food. You're also placed in a small group with others on similar journeys for peer support.

The support continues throughout your programme, not just at the start.
Can I stay on a lower dose if it's working for me?
Yes, you can stay on a dose that's working well for you.

Some people find excellent results at 5 mg or 7.5 mg of Mounjaro and choose to stay there.

Others need to gradually move up to 15 mg. The clinical team will work with you to find what's right based on your weight loss, side effects, and goals.

It's not one-size-fits-all; the decision is made together with the clinical team.
Can I switch to Second Nature from another provider and keep my current dose?
Yes, in most cases you can continue your current dose after a clinical assessment.

Our prescribing pharmacists will review your current medication, how long you've been taking it, and your medical history. If you're stable and everything checks out medically, you can typically continue rather than starting from the beginning.

You'll complete a health questionnaire and have a consultation with our clinical team, then get access to the full programme alongside your medication.
Can I cancel or pause at any time? Am I locked into a contract?
You can cancel anytime with no penalties or a long-term contract.

If you're thinking about cancelling because of side effects, cost, or feeling stuck, it's worth speaking to your health coach first - they might be able to help.
How do I get help if I experience severe side effects?
For mild side effects like nausea or constipation, message your health coach.

For moderate or persistent issues, they'll escalate to the clinical team. For severe symptoms (severe abdominal pain, allergic reactions), contact 111 or go to A&E immediately; don't wait to message us first.

Common side effects typically improve over time. Our research showed 69% of participants reported no side effects by month 12.
Who is your clinical team? Are they qualified doctors?
Our prescribing team are independent prescribing pharmacists registered with the General Pharmaceutical Council. They handle all medication decisions and clinical oversight.

Your health coaches are UK-registered dietitians or nutritionists with specialist training in GLP-1 medications. Dr Rachel Hall (MBChB) provides medical review and oversight.
How is Second Nature different from other providers?
We've had the privilege of working with the NHS for over eight years, helping people across the UK take meaningful steps toward a healthier, happier life.

Our programmes are designed to meet people where they are, whether that means support with weight loss through compassionate one-to-one health coaching, or access to the latest weight-loss medications (like Mounjaro and Wegovy) delivered alongside expert care from a multidisciplinary team of doctors, psychologists, dietitians, and personal trainers.

At the heart of everything we do is a simple belief: real, lasting change comes from building better habits, not relying on quick fixes. We're here to support that change every step of the way.

With over a decade of experience, thousands of lives changed, and a long-standing record of delivering programmes used by the NHS, we believe we're the UK's most trusted weight-loss programme.

We hope to offer you something invaluable: peace of mind, and the support you need to take that first step.

If you're comparing providers, you can also read our guides on how to buy Mounjaro online and buy Wegovy online.
Can I switch between weight loss medications?
Yes. If you find that one medication isn't working for you, either because you aren't losing enough weight or because the side effects aren't tolerable, let the clinician know. The clinician will typically have a discussion with you to determine what the issue is and if a change in medication would be in your best interest. You should note that some of the weight loss medications work similarly and have similar side effects. Therefore, switching medications does not necessarily mean that you'll lose more weight or that your side effects will change. When you switch from one medication to another, the same protocol is followed as if you are starting your weight loss journey afresh. This means that you will be prescribed the lowest dose of the new medication to begin and then gradually you'll work up to larger doses as your tolerability increases.
Can I start at a higher dose?
For Wegovy (semaglutide) and Mounjaro (tirzepatide), not unless you're already being prescribed the same weight loss medication by another provider. For Orlistat, there is only one dose offered on this service, and there is no escalation/titration path. Both Wegovy and Mounjaro have been designed with a set titration path for your safety and wellbeing (a titration path is when the dose is increased each month). This staggered approach also helps to reduce the impact of any gastrointestinal (GI) side effects by giving your body time to adjust to the medication. Some patients may even find that they need to titrate more slowly than other patients in order to give their body more time to get used to the medication.
Why are there different dose strengths?
For Orlistat, whilst there are two dose strengths available in the UK, only one dose strength (60mg) is available on this service. The difference in dose strengths for Orlistat is tied to patient eligibility and how much oversight from a clinician is required. The different doses of Wegovy and Mounjaro are part of a set titration path with your safety and wellbeing in mind. Weight loss medications commonly cause gastrointestinal (GI) side effects. The titration path for both Wegovy and Mounjaro starts you at a low initial dose of medication and then gradually increases your dose over time. This helps to reduce the impact of these side effects by giving your body time to adjust.
Do I have to increase my dose each month?
That depends. While most patients follow the set titration path for Wegovy and Mounjaro (which means that their dose is increased each month), other patients remain on the same dose for more than 1 month in order to allow their body more time to adjust to the medication. It all comes down to your body and how you tolerate the medication. The clinician will work with you to ensure that the next dose up is safe and effective for you. If you're having more side effects than usual, or you find that the side effects aren't tolerable, let your clinician know. You may be prescribed the same dose again or, in some cases, have your dose lowered if needed. If you're taking Orlistat, your dose won't increase at all. You'll take the same dose of the medication throughout your treatment.
How quickly will I lose weight?
Many patients start to notice weight loss within a month of starting medication. However, for some patients, it can take longer. Based on a clinical trial, patients taking 2.4 mg of Wegovy (semaglutide) can expect to lose up to 15% of their body weight after 68 weeks. In a separate clinical trial, patients taking Mounjaro (tirzepatide) 10 mg or 15 mg lost up to 20% of their body weight after 36 weeks. For patients taking Orlistat 60mg in a clinical trial, 46% lost at least 5% of their body weight in 6 months and 16% of patients lost 10%. In all clinical trials, patients were using the medication alongside a change in lifestyle (i.e. a reduced calorie diet and increased physical activity). If within six months of being on Wegovy or Mounjaro, or within three months of being on Orlistat, you do not lose at least 5% of your body weight, the clinician will work with you to understand why and, together, you'll decide if it is in your best interest to continue with the medication.
How long will I need to take the medication?
For Wegovy and Mounjaro, this is entirely up to you. The medications prescribed are intended for long-term use and sustainable weight maintenance, rather than being a quick fix. Once your rate of weight loss has stabilised and/or you've reached your target weight, the clinician will have a chat with you to understand whether continuing your weight loss treatment is in your best interest. For Orlistat, treatment should not exceed six months.
What if I don't lose any weight?
Some patients start to lose weight within a month of starting medication, but for others it may take longer. It's important to consistently take your medication as prescribed and to make diet and lifestyle changes alongside this. If within six months of being on Wegovy or Mounjaro, or within three months of being on Orlistat, you do not lose at least 5% of your body weight, the clinician will work with you to understand why and, together, you'll decide if it is in your best interest to continue with the medication.
What if I need to take a break from my weight loss medication?
This is entirely understandable. However, you should note that the medication is designed to be used long-term, without gaps or breaks. It takes time for your body to get used to the medication and, for Wegovy and Mounjaro, for you to build up your tolerance of the maintenance dose. Because of this, a gap or break of 2 doses or more when taking Wegovy or Mounjaro typically means that you'll need to start over. This means you'll have to begin on the starting dose when you decide to start taking the medication again. Orlistat is designed for consistent, daily use alongside meals containing fat, but it can be taken intermittently if you miss a meal or eat a fat-free meal. If you regularly need to take breaks from medication, it may be worth discussing this with the clinician to determine whether the medications prescribed are the most appropriate course of action for you.
Will I get side effects?
Weight loss medications commonly cause gastrointestinal (GI) side effects. These should subside in time and, in many instances, can often be managed by diet modification and over the counter medications. Side effects are most likely to be experienced during dose escalations (if you are taking Wegovy or Mounjaro) or when you first start treatment (if you are taking Orlistat). Some of the very common side effects for Wegovy (affecting 1 in 10 patients) include: Headaches, Vomiting, Diarrhoea, Constipation, Nausea, Bloating, Fatigue, Weakness. Some of the very common side effects for Mounjaro (affecting 1 in 10 patients) include: Vomiting, Diarrhoea, Constipation, Nausea. Some of the very common side effects for Orlistat (affecting 1 in 10 patients) include: Oily spotting, Flatus (gas) with discharge, Faecal urgency, Fatty oily stool, Oily evacuation, Flatulence (gas), Soft stools.

You can also read our detailed Mounjaro side effects guide and Wegovy side effects guide.
What can I do to manage common side effects effectively?
For nausea and mild abdominal pain, try reducing your meal size. Aim for smaller, more frequent meals that have an appropriate protein content and are not high in fat. Eat slowly, remain hydrated, and focus on simple, plain foods. If your lack of appetite is extreme, it's important to set reminders to eat and maintain proper nutrition. It may help to keep a food diary, or to eat whenever you do feel hungry, even if this is not at a normal mealtime. For issues with bloating, try to remember to eat small, more frequent meals and to eat slowly. Avoid fizzy drinks and be sure to take small sips. If you are experiencing headaches, stay hydrated and avoid too much screen time. It may also be helpful to get some fresh air and to lie down for a rest or take a nap. When diarrhoea occurs, it's important to stay hydrated and avoid caffeine. Continue to eat, but make sure your meals are small and frequent and that you eat slowly. Reduce your intake of fatty foods and insoluble fibre and consider taking some probiotics. If instead you become constipated, ensure that you remain hydrated and move about regularly. Consume regular and balanced meals and check your overall intake of fibre. If you are experiencing side effects associated with Orlistat, try reducing your dietary consumption of fat.
Are the medications addictive?
No, Wegovy, Mounjaro, and Orlistat are not addictive or habit-forming.
How does Orlistat work?
Orlistat is a hard capsule pill taken up to three times daily that works in the stomach and intestines by blocking the enzymes (lipases) that break down dietary fats. This in turns prevents a percentage of the fats you've eaten (approximately one-third) from being absorbed into the body. Instead, this undigested fat is excreted with your stools. This ultimately creates a calorie deficit that aids in weight loss.
Do I need a prescription for Orlistat?
No, you do not need a prescription for the dose of Orlistat (60mg) offered on this service. Whilst it is not a prescription medication, however, it is still a pharmacy medicine, which means that it must be obtained from a pharmacy and used under supervision. There is a 120mg dose of Orlistat available in the UK that is a prescription medication. However, this dose is not offered as part of the service.
How do I take Orlistat?
Orlistat is taken up to three times a day, every day. You should take it by mouth, with water, either immediately before, during, or up to one hour after each main meal. If you miss a meal, or your meal contains no fat, you should skip that dose of Orlistat.
What are the side effects of Orlistat?
Some of the very common side effects for Orlistat (affecting 1 in 10 patients) include: • Oily spotting • Flatus (gas) with discharge • Faecal urgency • Fatty oily stool • Oily evacuation • Flatulence (gas) • Soft stools For most patients, these side effects are experienced when they first begin treatment and will often subside over time. To reduce side effects, you can decrease your dietary fat consumption.
Can I use Orlistat if I am pregnant or breastfeeding?
No, you should not take Orlistat if pregnant or breastfeeding. It's also recommended to use an additional barrier contraceptive method (e.g. condoms) whilst taking Orlistat, as, if you experience severe diarrhoea as a side effect, this may lead to oral contraception failure.
Can I drink alcohol while taking Orlistat?
Yes, you can drink alcohol whilst taking Orlistat. However, moderate alcohol consumption is recommended, as alcohol may worsen some of the common side effects patients may experience whilst taking the medication and hinder weight loss goals.
Is Orlistat safe?
Orlistat is generally safe for individuals who meet the established criteria, i.e. those who are overweight or obese and who do not have exclusionary conditions or factors. It is important, as with any medication, to use Orlistat as directed under the guidance of a clinician. The screening and consultation process in place helps to determine if Orlistat will be safe and effective for you. The ongoing check-ins help to ensure that this remains the case for the duration of your time with the service. As with any medication, there are potential side effects associated with Orlistat, which vary in severity and frequency for different patients. You can view the full list of these side effects, as well as other important information, in the Patient Information Leaflet for Orlistat.
Can I get Orlistat free on the NHS?
Orlistat may be available in some areas for weight reduction via the NHS. You can check with your GP if it is available for you.
Can I buy Orlistat privately?
Yes, you can buy Orlistat (60mg) privately from any licensed pharmacy in the UK, although it will require a pharmacist consultation as it is a Pharmacy Medication. If you are seeking to purchase Orlistat at a higher dose (120mg), you must have a valid prescription, as it is a Prescription Only Medication. The 120mg dose of Orlistat is not available as part of this service.
Where should I store my Orlistat?
Orlistat should be stored in its original container, kept securely closed at room temperature in a dry place away from heat, moisture, and direct light. Be sure to store the medication out of sight and reach of children and pets.
Can I travel with Orlistat?
Yes, you can travel with Orlistat. You should keep the medication in its original, labeled container and ensure that you pack it in your carry-on luggage so that it can remain at room temperature.