The Independent Pharmacy

How Long Does Orlistat Take to Work

Donald Grant
Dr Donald GrantMB ChB DRCOG MRCGP Dip.orth.medGP & Clinical Advisor

Reviewed on 24 May 2023

Embarking on a weight loss journey can often feel like a daunting task. With so many options like diets, exercises, and medications, it’s hard to know where to start and what will work. If you’ve been considering using Orlistat (as well as the branded version Xenical or the over-the-counter option Alli) to support your weight loss goals, you’re likely wondering:

How long does Orlistat take to work?

Some people have noticed a difference in the first 3 to 5 days. However, you need to remember that everyone’s experience might vary, and your weight loss timeline could look different. So, don’t be disheartened if you don’t notice a significant difference in the first 2-4 weeks of your weight loss treatment.

As professionals who assist many people struggling to lose weight, we at the Independent Pharmacy understand the impatience to see results fast. However, nurturing realistic expectations is a gentle step towards long-term success.

Understanding what to expect might help you to stick to your efforts and reach your goals.

Here’s all you need to know about the results you might see with Orlistat.

How Long Does It Take to See Results With Orlistat?

When starting any new weight loss medication or program, it’s natural to want to see results right away. However, Orlistat works gradually to support fat and calorie absorption over time to aid weight loss.

According to clinical studies, most overweight or obese patients beginning treatment with a 120mg Orlistat capsule taken 3 times per day with meals start to notice some initial weight loss within 2 to 4 weeks. However, the specific amount of weight lost can vary based on individual factors like diet, exercise, and metabolism.

In one 12-week clinical trial, participants taking a 120mg dose of Orlistat three times per day experienced an average body weight reduction of 5-10% from their initial weight. After continuing the Orlistat regimen for one year, the average total body weight loss increased to 10-15% for many patients.

We advise keeping an Orlistat intake and weight/measurement progress journal. This can help monitor your personal timeline and fat-blocking results. Embracing consistency and patience on your weight loss journey with Orlistat capsules can be a nurturing approach to self-care.

How Does Orlistat Work for Weight Loss?

To understand Orlistat’s timeline for weight loss, it helps to know how these capsules work in your body.

Orlistat is a medication that helps block the absorption of fat from the food you eat. It works in your digestive system and targets specific enzymes called lipases, which usually break down fat so your body can absorb it. Orlistat prevents these enzymes from doing their job, so the fat passes through your body without being absorbed.

These lipase enzymes typically break down the fat in your food so it can be absorbed. But when Orlistat is present, it blocks the lipases. This prevents them from breaking down the fat from your meals.

With the fat not properly digested, your body cannot absorb the calories from that fat. So, the undigested fat passes out of your body in your bowel movements. This forces your body to take more calories from your existing fat storage, which, over time, causes weight loss.

Essentially, Orlistat capsules promote weight loss by blocking the calories from fat in your diet from being absorbed and used by your body. While the undigested fat may cause oily spotting or stool, this shows that Orlistat is working to prevent fat and calorie intake.

Factors Influencing Orlistat’s Effectiveness

While Orlistat can be an effective weight loss aid for many people, there are some key factors that impact how well it works:


Every individual’s body responds differently. Some may experience quicker initial weight loss with Orlistat, especially those who burn calories faster, while others with a slower calorie burn rate might see a more gradual change. However, following the medication guidelines consistently can lead to meaningful weight loss for most.


Orlistat is most effective when combined with a low-fat, reduced-calorie diet. Eating high amounts of fat around the time you take an Orlistat capsule reduces its ability to block fat absorption. Following nutritional guidelines can boost results.


Adding exercise accelerates weight loss as Orlistat prevents the absorption of fat calories. Increased activity burns additional calories and boosts metabolism. Even light exercise, like walking 30 minutes a day, makes a difference.

The most successful Orlistat users combine the medication as prescribed with improved eating habits and increased physical activity. Tracking your lifestyle factors and their impact on your weight loss can help maximise your results with Orlistat capsules. Discuss any concerns with your healthcare provider.

How Do You Get the Best Results From Orlistat?

To get the most out of your Orlistat capsules for weight loss, here are some tips:

  1. Follow dosage instructions - Take one Orlistat capsule (120mg) three times a day with your main meals that have some fat in them. This enables Orlistat to block fat absorption consistently throughout the day. Take capsules during or up to 1 hour after meals.
  2. Eat a low-fat diet - Limit daily fat intake to 15-30% of calories to minimise side effects and enable Orlistat to work optimally. Focus on lean proteins, fruits, vegetables, whole grains, and low-fat dairy.
  3. Exercise regularly - Aim for 150 minutes of moderate exercise, like brisk walking per week, to boost calorie burning. Adding strength training also helps build metabolism-boosting muscle.
  4. Track your progress - Monitor your weight, measurements, body fat percentage, and any side effects in a daily journal. This helps tailor your program.
  5. Consult your doctor - Schedule regular check-ins to discuss your results, diet, physical activity, and any needed adjustments to get optimal outcomes.

By embracing healthy habits and following the recommended Orlistat regimen with kindness towards yourself, you are nurturing your body’s ability to support your weight loss goals. Let your healthcare provider know if you need help creating a balanced diet and active lifestyle plan.

How Should I Prepare for Weight Loss?

Making some preparations before beginning your Orlistat weight loss journey can set you up for success:

  1. Set gentle, realistic expectations - Aim for the steady progress of losing 1-2 pounds per week, avoiding extreme dieting, and nurturing your body. Expect that the rate of weight loss will be gradual. Stay patient and focused on long-term health.
  2. Get organised - Meal plan, shop for healthier ingredients, cook batches of low-fat recipes, and schedule exercise sessions. Having healthy habits established makes adherence easier.
  3. Involve your support system - Let family and friends know you are prioritising your health. Their encouragement through challenges can make a real difference.
  4. Address emotional issues - Evaluate your relationship with food and the emotional aspects of eating. Managing stressors and unhealthy thought patterns is key.
  5. Consult your doctor - Discuss any medical conditions, get health testing, and create a tailored weight loss plan with your healthcare provider.

With the right mindset, plan, support, and expert guidance, you can set the stage for Orlistat and improved nutrition and exercise to facilitate weight reduction success. Let your doctor know if you need help with lifestyle changes.

How Can I Reduce My Fat Intake?

Cutting down on fat can be tricky when starting Orlistat, but with some simple swaps and adjustments, you’ll be a pro in no time.

  • First up, switch to low-fat versions of your dairy faves. Go for skim or 1% milk, part-skim mozzarella, and Greek yoghurt with less than 3g fat per serving. Just check the labels.
  • When it comes to meat, choose leaner options like a boneless, skinless chicken breast or a centre-cut pork chop. Limit bacon, ribs, sausage, and other fatty meats.
  • The cooking method matters, too. Skip frying and go for roasting, baking, grilling or steaming your foods to cut the added fats.
  • To avoid extra hidden fats, steer clear of creamy sauces, oily dressings, buttery spreads and anything deep-fried. Not to worry, you’ve got delicious, healthier options like vinaigrettes, salsas, chimichurris, pestos, herb rubs, and all your favourite spices.
  • Eating more fruits, veggies, whole grains, beans, lentils, nuts, and seeds will keep you full while adding nutrition.
  • Check those nutrition labels and stick to less than 3g saturated fat per serving. Measuring oil and nut butter is also key.
  • Lastly, drink plenty of water and limit sugary drinks, juice and alcohol. They can pack hidden calories.

Following a lower-fat diet takes commitment, but your improved health is so worth it. Ask your doctor for a referral to a nutritionist if you need guidance tailoring your meal plan. Small changes make a real difference!

What to Do if Orlistat Is Not Working?

Not seeing expected results after consistently taking Orlistat? Don’t get discouraged. There are some simple troubleshooting steps to get you back on track:

  • First, take an honest look at what you’re eating. Are fatty foods sneaking in? Limiting high-fat meals will help Orlistat work its best.
  • Next, assess your activity levels. Have you been a couch potato? Adding more movement, like taking the stairs or parking farther away, can get your metabolism fired up.
  • Be sure to take Orlistat correctly - one capsule before, during or just after meals that contain fat. Consistency is key.
  • Some medications don’t jive well with Orlistat, so talk to your pharmacist or doctor about potential interactions.
  • Rule out any underlying issues by getting your thyroid and other hormone levels checked via bloodwork. Medical problems can stall weight loss.
  • Chat with your doctor openly about your regimen. They may tweak your Orlistat dose or recommend coupling it with other exercise, behavioural or diet tactics.
  • If the side effects that affect your digestive tract bother you, discuss switching to a different weight loss medication with fewer digestive issues.

Plateaus happen, but don't go rogue and increase your dose without medical approval. With some troubleshooting guidance, you'll get back on track!


Here are answers to some frequently asked questions about Orlistat for weight loss:

How much weight can I lose in a week with Orlistat?

Expect to lose around 1-2 pounds per week on Orlistat, more if you follow a low-calorie diet and exercise plan. Rapid weight loss over 2 pounds weekly is not recommended.

How do you know Orlistat is working?

You may see oily spots in your underwear or stool. Though the absence of these does not mean that the medication is not working. You will know it is working as your weight begins to reduce. Losing weight as expected over time means it is effective.

Has anyone lost weight on Orlistat?

Yes, in clinical studies and real-world usage, many people have safely lost weight with Orlistat in conjunction with diet and exercise. However, individual results vary.

What happens if you eat fat while taking Orlistat?

Orlistat works by blocking fat absorption, so dietary fat will pass through your body undigested. Be prepared for symptoms like gas, bloating, abdominal pain, and loose stools after eating high-fat foods when taking Orlistat.

Why am I gaining weight on Orlistat?

If your weight increases while taking Orlistat as directed, discuss your diet and lifestyle with your doctor. Consuming high-calorie foods, inadequate exercise, fluid retention, or muscle gain can contribute to gain. Adjustments may be needed.

What is the best time to take Orlistat?

The best practice is taking one 120mg Orlistat capsule within 1 hour before, during, or up to 1 hour after each main meal containing fat. Consistency around meal times is important.


Orlistat: Uses, Interactions, Mechanism of Action | DrugBank Online

Effect of Orlistat on Weight and Body Composition in Obese Adolescents: A Randomized Controlled Trial | Obesity | JAMA | JAMA Network

Predictive value of early weight loss in obesity management with orlistat: an evidence-based assessment of prescribing guidelines - PubMed (

Orlistat - StatPearls - NCBI Bookshelf (

Frontiers | The Effect of Orlistat on Sterol Metabolism in Obese Patients (

Study of Effect of Low-Calorie Diet, Exercise and Orlistat on Weight and BMI of the Obese Patients: A Prospective Study | Insight Medical Publishing (

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