Orlistat (the primary ingredient) is used with an individualized low-calorie, low-fat diet and exercise program to help people lose weight. In comparison, prescription Xenical is used in overweight people who may also have hypertension (high blood pressure), diabetes, high cholesterol, or heart disease.
The medical definition of overweight is having a body mass index (BMI) of 25 to 29.9. BMI is calculated using your height and weight. BMI calculators and charts are available online.
Alli contains orlistat as its active ingredient. Orlistat belongs to a drug class known as lipase inhibitors. It works for weight loss by blocking your digestive system from absorbing fat from your diet. It helps your body get rid of the fat by eliminating it in your stool.
Alli is available OTC. It comes as a 60-milligram capsule that you take orally (by mouth). A higher strength of this drug, Xenical 120 milligram, is available by prescription.
What Is Alli Used For?
The Food and Drug Administration (FDA) has approved Alli to aid in weight loss in adults 18 and older who are medically overweight. The drug was first approved in 1999. It is meant to be used along with a reduced-calorie, low-fat diet and regular exercise.
Brand Name(s): Alli, Xenical
Drug Availability: Alli (OTC), Xenical (prescription)
Administration Route: Oral
Therapeutic Classification: Lipase inhibitor
Available Generically: No
Controlled Substance: N/A
Active Ingredient: Orlistat
Dosage Form(s): Capsule
Alli is a short-term weight-loss drug. In clinical trials ranging from six weeks to six months long, this medication was shown to be effective for weight loss in adults, compared to diet alone.
How to Take Alli
Alli comes as a capsule that you take by mouth. You’ll take one capsule of Alli with each meal containing fat, up to three times per day.
Keep in mind that Alli works by blocking fat from getting absorbed. If you skip a meal, or if your meal does not contain fat, you can skip that dose.
Be sure to check nutritional labels to learn how much fat is in the foods you are eating. Your meals should contain balanced amounts of protein, carbohydrates, and fat. A good rule of thumb is to aim for a diet that is less than 30% fat. If you take Alli with a very high-fat meal (more than 30% fat content), you are more likely to experience unpleasant side effects.
Alli affects the way your body absorbs fat, and it can also interfere with how your body absorbs certain vitamins. These vitamins are known as fat-soluble vitamins and include vitamins A, D, E, and K.
Storage
Store Alli at room temperature in a dry place, away from light and moisture. Do not store in a bathroom. Keep Alli and all medications away from children and pets.
What Are the Side Effects of Alli?
This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a medical professional. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.
Common Side Effects
Common side effects of Alli include:
Gas with oily spotting Loose stools Oily stools More frequent bowel movements that may be hard to control
Note that these side effects may become worse if you take Alli with a high-fat meal.
To minimize the risk of side effects, you should take Alli with a meal containing 30% or less of its calories from fat. If your meal does not contain any fat, you should skip that dose of Alli.
Severe Side Effects
Rarely, Alli may cause severe side effects.
These side effects and their related symptoms may include:
Liver problems: Symptoms may include severe abdominal pain or swelling, yellowish skin or eyes, and dark urine. Kidney stones: Symptoms of kidney stones may include back or side abdominal pain, difficulty urinating, and red or pink urine. Allergic reaction or anaphylaxis: Symptoms of anaphylaxis may include rash, hives, swelling around the lips, tongue, and face, and trouble breathing. Seek emergency medical assistance right away if you have these symptoms.
Long-Term Side Effects
Long-term use of orlistat may be associated with vitamin D deficiency, osteoporosis, gallbladder problems, and an increased risk of colon cancer. But, more research is needed to confirm if these safety concerns are valid.
Alli is not meant for long-term use. Consult your healthcare provider if you are not seeing results within a few months of starting Alli.
Dosage: How Much Alli Should I Take?
Missed Dose
Alli should be taken with a meal containing fat. If you forget to take your dose and it has been less than an hour since your meal, you can still take your dose.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
For oral dosage form (capsules): For treatment of obesity: Adults and teenagers—120 milligrams (mg) three times a day with meals containing fat. Children younger than 12 years of age—Use and dose must be determined by your doctor.
If you skip a meal or eat a nonfat meal, you should also skip your dose of Alli.
Overdose: What Happens If I Take Too Much Alli?
After you take Alli, its active ingredient, orlistat, stays in your digestive tract. This drug does not absorb into your blood to any significant extent. So, an overdose of Alli is not expected to be dangerous.
Still, if you think you or someone else took too much Alli, you should consult a healthcare professional. In some cases, they may recommend that you go to a hospital for treatment or observation.
Precautions
What Are Reasons I Shouldn’t Take Alli?
You should not take Alli if:
Using this medicine while you are pregnant can harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using this medicine, tell your doctor right away.
For patients with diabetes: Weight loss may result in an improvement in your condition, and your doctor may need to change your dose of oral diabetes medicine or insulin.
This medicine may cause a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you or your child have a rash; itching; hoarseness; trouble breathing; trouble swallowing; or any swelling of your hands, face, or mouth while you are using this medicine.
Stop using this medicine and check with your doctor right away if you or your child have pain or tenderness in the upper stomach; pale stools; dark urine; loss of appetite; nausea; unusual itching; unusual tiredness or weakness; or yellow eyes or skin. These could be symptoms of a serious liver problem.
This medicine may increase your risk of having kidney stones. Check with your doctor right away if you or your child have blood in the urine, nausea and vomiting, pain in the groin or genitals, or sharp back pain just below the ribs.
Weight loss with this medicine may increase your risk of having gallstones. Check with your doctor right away if you or your child have severe stomach pain with nausea and vomiting.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
You are not overweight. You have been diagnosed with malabsorption (problems absorbing nutrients from food). You are taking cyclosporine. You are pregnant or breastfeeding.
What Other Medications May Interact With Alli?
Alli can interact with certain medications.
Before taking Alli, make sure to give a list of all prescription and OTC medications, including vitamins and supplements, to your healthcare provider for review.
Some medications that may interact with orlistat (the active ingredient in Alli capsules) include:
Jantoven (warfarin), also known by its former brand name Coumadin Thyroid medications such as Synthroid (levothyroxine) Seizure medications such as Lamictal (lamotrigine) and Depakote (divalproex) Cordarone (amiodarone), a heart medication
Before taking Alli, check with your healthcare provider if you are taking the above medications. In some cases, they may need to adjust the dosage of your other medication. Or they may advise you to separate doses of Alli from the other drug by at least four hours.
In other cases, they may advise you not to take Alli because it may cause certain drugs to be less effective.
Alli should not be taken with any other weight loss drug or product.
People taking Alli should take a multivitamin to help prevent vitamin deficiencies. Be sure to take the multivitamin at bedtime or at least two hours apart from orlistat.
What Medications Are Similar?
Below is a list of FDA-approved weight loss drugs that may be considered alternatives to Alli:
Adipex-P (phentermine): stimulant drug available as an oral tablet or capsule Contrave (naltrexone and bupropion): combination drug that comes as an oral tablet Qsymia (phentermine and topiramate): combination drug that comes as an oral capsule Saxenda (liraglutide): daily injection, classified as GLP-1 agonist Wegovy (semaglutide): GLP-1 agonist that you inject once weekly. Xenical (orlistat): oral capsule that contains a higher strength of orlistat than Alli
These medications work differently than Alli but are also used to aid in weight loss. While Alli is available OTC, the medications listed above are available by prescription only.
Keep in mind that all weight loss drugs should be used along with a healthy diet and regular exercise.
Talk to your healthcare provider to determine if one of these options is right for you.
How Can I Stay Healthy While Taking Alli?
Trying to lose weight can be an overwhelming task. Keep in mind that long-term weight management requires a shift in how you eat and live your life; it is not something that happens overnight.
With continued use of Alli, these side effects should become less problematic, especially as you learn to avoid high-fat meals. Taking Alli with a high-fat diet makes the digestive side effects worse.
But, Alli is an OTC capsule and contains 60 milligrams of orlistat. Xenical is available by prescription and contains 120 milligrams of orlistat.
While taking Alli, it is important to follow a reduced-calorie, low-fat diet. Aim for about 30% or less of your total calories to come from fat. Examples of foods containing fat include oils, fried foods, and red meat. This will help lessen unpleasant side effects that may occur while taking Alli. It will also help the medication work more effectively toward your weight loss goal.
Remember that you are not alone in your efforts to reach a healthy weight. Healthcare professionals can help. Consider involving a friend, partner, or a potential support group to help you stay accountable and to make the journey more fun.
