Alli weight-loss pill: Does it work?
Medically reviewed by Drugs.com. Last updated on Mar 19, 2021.
Alli (pronounced AL-eye) is an over-the-counter drug meant for overweight adults struggling to shed excess pounds. With its easy access and weight-loss promises, is Alli your answer for losing weight?
What is Alli?
Alli is a 60-milligram, over-the-counter version of orlistat (Xenical), a 120-milligram prescription drug. Both Alli and Xenical are meant to be used as part of a weight-loss plan that includes a low-calorie, low-fat diet and regular physical activity.
Alli is approved for use in adults 18 and older who have a body mass index (BMI) of 25 or more. Xenical is approved for use in adults with a BMI of 30 or more (obese), and those with a BMI of 27 to 29 (overweight) who have other health risk factors such as high blood pressure or diabetes.
Are there concerns about orlistat?
The Food and Drug Administration (FDA) published a safety review of orlistat in 2010 because of rare reports of serious liver injury in people using it. The FDA found no evidence to confirm that orlistat was the cause of the reported liver injuries.
However, Alli and Xenical labels were revised because of the reports. Talk to your doctor immediately if you have signs or symptoms that may indicate liver injury:
- Loss of appetite
- Yellow eyes or skin
- Light-colored stool
- Brown urine
How does Alli work?
Orlistat (the active ingredient in Alli) promotes weight loss by decreasing the amount of dietary fat absorbed in your intestines.
Lipase, an enzyme found in the digestive tract, helps break down dietary fat into smaller components, so it can be used or stored for energy. Orlistat inhibits the work of lipase. When you take the drug with a meal, about 25 percent of the fat you consume isn't broken down and is eliminated through bowel movements.
How much weight could I lose using Alli?
Alli may help you lose weight, but the weight loss will likely be modest — perhaps just a few pounds more than you would lose with diet and exercise alone.
More than 40 percent of people taking Alli while following a calorie-restricted diet and increasing physical activity lost 5 percent or more of their body weight within a year. Clinically meaningful weight loss — enough weight loss to begin lowering the risk of cardiovascular disease, diabetes and other diseases — is generally defined as 5 percent or more of body weight.
People who ate a calorie-restricted diet, exercised regularly and took Alli lost an average of 5.7 pounds (2.6 kilograms) more in one year than did people who only dieted and exercised.
How is Alli taken?
One 60-milligram Alli pill is taken within an hour of a fat-containing meal up to three times a day. Daily fat intake should be distributed over the three main meals and should be no more than 30 percent of total calories. The manufacturer recommends a fat intake of about 15 grams a meal.
If you eat a meal that contains no fat, then you don't need a dose of Alli. If you take Alli with a high-fat meal, you will likely experience more-severe gastrointestinal side effects.
Alli can reduce the absorption of fat-soluble nutrients, including beta carotene and vitamins A, D, E and K. Take a multivitamin at bedtime and at least two hours after your last dose of Alli.
Does Alli have side effects?
The active ingredient in Alli, orlistat, causes gastrointestinal side effects related to undigested fats passing through your digestive system. They generally subside over time and with appropriate use of the medication. These side effects include:
- Abdominal pain or discomfort
- Oily discharge from the anus
- Gas with oily anal discharge
- Oily stools
- More-frequent bowel movements
- Urgent or hard-to-control bowel movements
Other possible side effects include:
- Back pain
- Upper respiratory infection
When shouldn't you take Alli?
Before taking Alli, talk with your doctor about possible interactions with other medications, particularly if you take medications for any of the following conditions:
- Thyroid disease
- Irregular heartbeat
- Cardiovascular disease
It's also important to check with your doctor if you've had:
- Gallbladder problems
- Kidney stones
- Irritable bowel syndrome
Alli isn't recommended if you:
- Are at a healthy weight
- Have had an organ transplant
- Are taking cyclosporine (Neoral, Sandimmune, others)
- Have problems already absorbing food
- Are pregnant or breast-feeding
How long do I need to take Alli?
A weight-loss plan with diet, exercise and drug therapy is generally considered successful if you lose about 1 pound (0.5 kilogram) a week during the first month and have lost 5 percent or more of the pre-treatment body weight within one year.
If the treatment is successful, you are more likely to keep weight off or lose more weight if you continue with the diet, exercise and drug treatment plan.
Most weight loss with the medication occurs within the first few months. If you have adhered to the diet and exercise plan and have not lost at least 5 percent of your initial body weight within a few months, continuing the medication may be of little benefit.
If you haven't lost 5 percent of your body weight within a year on the plan, discontinuing the drug would be a reasonable choice. The risks, side effects and cost associated with taking the medication likely override any potential benefit.
How does Alli fit into a healthy weight-loss plan?
Alli isn't an easy answer to weight loss. Losing weight and keeping it off require a commitment to eat a healthy diet and get regular physical activity.
Work with your doctor to evaluate the potential benefits and risks of Alli or any other weight-loss drugs. As a team, you and your doctor can create the right weight-loss plan for you.