What is Orlistat: Uses, Dosage, Side Effects and More

Orlistat is a prescription weight-loss medication that helps you lose weight by blocking some of the fat you eat from being absorbed in your intestines. Instead of being stored in your body, about 30% of the fat from your meals gets eliminated through bowel movements, which can support your weight loss goals when combined with a healthy diet and exercise.

What is Orlistat?

Orlistat is a lipase inhibitor that works directly in your digestive system to prevent fat absorption. It's one of the few FDA-approved medications specifically designed for long-term weight management in adults who are significantly overweight or obese.

This medication belongs to a class of drugs called pancreatic lipase inhibitors. Think of lipase as tiny scissors that cut up fat molecules so your body can absorb them. Orlistat essentially dulls these scissors, so less fat gets processed and stored in your body.

Orlistat is available in two strengths: 120mg by prescription (brand name Xenical) and 60mg over-the-counter (brand name Alli). The prescription version is stronger and typically recommended for people with more significant weight management needs.

What is Orlistat Used For?

Orlistat is primarily used to help adults lose weight and maintain weight loss when combined with a reduced-calorie diet. It's specifically designed for people who are obese or significantly overweight with weight-related health concerns.

Your doctor might recommend orlistat if your body mass index (BMI) is 30 or higher, or if your BMI is 27 or higher and you have weight-related conditions like high blood pressure, diabetes, or high cholesterol. These conditions often improve as you lose weight with proper treatment.

The medication can also help prevent weight regain after you've already lost weight. Many people find it easier to maintain their weight loss when they have this extra support, especially during the challenging maintenance phase.

How Does Orlistat Work?

Orlistat works by blocking pancreatic lipase, an enzyme your body uses to break down dietary fats. When this enzyme is blocked, your body can't absorb about 30% of the fat you eat, and this unabsorbed fat passes through your digestive system.

This is considered a moderately strong weight-loss medication because it directly interferes with nutrient absorption. Unlike some weight-loss drugs that affect your brain or metabolism, orlistat works locally in your digestive tract where fat digestion happens.

The medication starts working within 24 to 48 hours of taking it. You'll likely notice changes in your bowel movements fairly quickly, which is a normal sign that the medication is preventing fat absorption as intended.

How Should I Take Orlistat?

Take orlistat exactly as prescribed by your doctor, typically three times daily with each main meal that contains fat. You can take it with your meal or up to one hour after eating, but it works best when taken with food.

If you eat a meal that contains no fat, you can skip that dose since there's no fat for the medication to block. Always take orlistat with water, and try to eat your meals at roughly the same times each day to maintain consistent effects.

For best results, aim to eat meals that contain about 30% of calories from fat, distributed evenly throughout the day. Eating too much fat at once can increase the likelihood of uncomfortable digestive side effects.

You should also take a daily multivitamin containing vitamins A, D, E, and K at bedtime or at least 2 hours before or after taking orlistat. This helps ensure you get essential fat-soluble vitamins that might be reduced due to decreased fat absorption.

How Long Should I Take Orlistat For?

Most people take orlistat for several months to a few years, depending on their weight loss goals and how well they respond to treatment. Your doctor will typically evaluate your progress after 12 weeks to determine if you should continue.

If you haven't lost at least 5% of your starting weight after 12 weeks of consistent use, your doctor might suggest discontinuing orlistat and exploring other weight management options. This doesn't mean you've failed – it simply means this particular medication might not be the right fit for your body.

Some people benefit from taking orlistat long-term to help maintain their weight loss, especially if they have ongoing weight-related health conditions. Your doctor will work with you to determine the best duration based on your individual health needs and response to treatment.

What Are the Side Effects of Orlistat?

The most common side effects of orlistat are digestive and happen because unabsorbed fat passes through your system. These effects are generally manageable and often improve as your body adjusts to the medication and you learn to eat appropriately.

Here are the digestive side effects you might experience, especially when you first start taking orlistat or eat too much fat:

• Oily or fatty stools that may be difficult to control
• Increased frequency of bowel movements
• Urgent need to have bowel movements
• Gas with oily discharge
• Stomach pain or cramping
• Nausea or vomiting

These digestive effects usually become less bothersome as you adjust your diet to include less fat and your body adapts to the medication. Most people find that following a lower-fat diet significantly reduces these side effects.

Less common but more serious side effects can occur, though they're relatively rare. You should contact your doctor if you experience severe stomach pain, yellowing of skin or eyes, dark urine, loss of appetite, or signs of kidney problems like changes in urination.

Some people may also experience headaches, back pain, or upper respiratory infections, though these are generally mild and temporary. Always discuss any concerning symptoms with your healthcare provider.

Who Should Not Take Orlistat?

Orlistat isn't suitable for everyone, and there are several important conditions and situations where this medication should be avoided for safety reasons. Your doctor will carefully review your medical history before prescribing it.

You should not take orlistat if you have chronic malabsorption syndrome, a condition where your body already has trouble absorbing nutrients from food. Adding orlistat could worsen this problem and lead to serious nutritional deficiencies.

People with gallbladder problems should also avoid orlistat, as it can potentially worsen these conditions. If you have a history of gallstones or other gallbladder issues, your doctor will likely recommend alternative weight management approaches.

If you're taking cyclosporine (an immunosuppressive medication), orlistat can interfere with its absorption, potentially making it less effective. Your doctor will need to carefully monitor your cyclosporine levels if both medications are necessary.

Pregnant and breastfeeding women should not use orlistat, as weight loss during these times isn't recommended and the medication's effects on developing babies aren't fully understood. Children under 12 should also not take this medication.

Orlistat Brand Names

Orlistat is available under two main brand names, each with different strengths and availability. Xenical is the prescription version that contains 120mg of orlistat per capsule and requires a doctor's prescription.

Alli is the over-the-counter version that contains 60mg of orlistat per capsule, which is half the strength of Xenical. You can purchase Alli at most pharmacies without a prescription, though it's still wise to consult with a pharmacist or healthcare provider before starting.

Both versions work the same way, but Xenical is typically recommended for people who need more significant weight loss support or have weight-related health conditions that require closer medical supervision.

Orlistat Alternatives

If orlistat isn't right for you, several other weight management options are available, both prescription and non-prescription. Your doctor can help you explore these alternatives based on your specific health needs and weight loss goals.

Other FDA-approved weight loss medications include semaglutide (Wegovy), liraglutide (Saxenda), and phentermine-topiramate (Qsymia). These work differently than orlistat – they typically affect appetite and satiety rather than blocking fat absorption.

Non-medication approaches include working with a registered dietitian, joining a structured weight loss program, increasing physical activity, or considering bariatric surgery for people with severe obesity. Often, a combination of approaches works best.

Lifestyle modifications remain the foundation of any successful weight management plan, regardless of whether you use medication. This includes developing sustainable eating habits, regular physical activity, stress management, and adequate sleep.

Is Orlistat Better Than Other Weight Loss Medications?

Whether orlistat is better than other weight loss medications depends on your individual health profile, weight loss goals, and how well you tolerate different types of treatments. Each medication has unique benefits and considerations.

Orlistat has the advantage of working locally in your digestive system rather than affecting your brain chemistry or metabolism. This can be preferable for people who are sensitive to medications that affect the central nervous system or have certain mental health conditions.

However, newer medications like semaglutide often produce more significant weight loss with fewer digestive side effects. These medications work by mimicking hormones that regulate appetite and blood sugar, which some people find easier to tolerate.

The "best" medication is the one that you can take consistently, that fits with your lifestyle, and that helps you achieve sustainable weight loss without intolerable side effects. Your doctor can help you weigh the pros and cons of each option.