Ad-free. Unbiased. Consumer-powered.

 
Product Guru
About Us FAQ Contact Us

Alli Weight-Loss Pill: Does it Work?

Alli Weight-Loss Pill: Does it Work?
Jared Cole

By Jared Cole

April 19, 2025


By Mayo Clinic Staff


Introduction to Alli

Alli, pronounced as AL-eye, is an over-the-counter drug designed to aid weight loss in overweight adults. This medication, categorized as a 60-milligram version of orlistat, complements a comprehensive weight-loss strategy involving a low-calorie, low-fat diet and consistent physical activity. Its prescription counterpart, Xenical, is available at 120 milligrams.


Alli is FDA-approved for adults 18 and older with a BMI of 25 or more, whereas Xenical suits those with a BMI of 30 or over, including those with BMI ranging from 27 to 30 if they have accompanying health risks like hypertension or diabetes.


Understanding How Alli Works

The active component of Alli, orlistat, facilitates weight loss by reducing the absorption of dietary fats in the intestines. This process is achieved by inhibiting lipase, the enzyme that breaks down fats for storage or energy. Consequently, approximately 25% of ingested fat is excreted in bowel movements when Alli is consumed with fat-containing meals.


Clinically, the effectiveness of Alli is observed when used alongside calorie-restricted diets and exercise, often resulting in a modest weight loss. In studies, over 40% of participants taking Alli lost 5% or more of their body weight within a year, potentially lowering the risks of heart disease, diabetes, and other conditions.


How to Use Alli

For optimal results, a standard recommendation is to take one Alli pill within an hour of a meal that contains fat, up to three times daily. It is imperative to distribute your daily fat intake evenly across three meals, ensuring it does not surpass 30% of total daily calories. If a meal is fat-free, skipping the dose is advisable to minimize digestive discomfort.


Notably, Alli hinders the absorption of fat-soluble nutrients, including vitamins A, D, E, and K, and beta-carotene. Therefore, taking a multivitamin at bedtime, or two hours post the final Alli dose, helps maintain nutritional balance.


Potential Side Effects of Alli

The consumption of Alli may lead to several digestive side effects, primarily resulting from undigested fats. Common symptoms include:


  • Stomach pain or upset stomach
  • Oily discharge from the anus
  • Gas with oily anal discharge
  • Oily stools
  • Increased frequency or urgency of bowel movements

Additional reactions might involve headaches, back pain, cold-like symptoms, and menstrual variations. These side effects typically subside with time and correct usage.


Precautions and Considerations

Before commencing Alli, it is essential to discuss with healthcare providers about possible interactions, especially if you utilize medications for diabetes, thyroid disease, heart conditions, seizures, or HIV. Additionally, caution is advised for individuals with past issues like gallbladder complications, kidney stones, or pancreatitis.


Alli is unsuitable for individuals at a healthy weight, those who have undergone organ transplants, are pregnant or breastfeeding, or experiencing malabsorption issues.


Evaluating Alli's Role in a Weight-Loss Plan

To achieve successful weight loss, while Alli can be a supplementary tool, it necessitates a committed approach towards a healthy lifestyle. This involves maintaining a calorie-conscious diet and performing regular physical exercises. Collaborating with a healthcare provider to develop a personalized weight-loss plan, including evaluating the risks and benefits of Alli or similar drugs, is advisable for achieving best results.


It should be noted that most weight loss occurs in the initial months of use. If after a few months there’s less than a 5% body weight reduction, considering cessation of Alli might be advantageous due to associated costs and side effects overshadowing the expected benefits.


Published by Mayo Clinic Staff on April 09, 2024


© 1998-2025 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.



If you're looking for a next-gen fat burner with whole-body benefits—not just a temporary thermogenic boost—Mitolyn may be the smarter, longer-lasting choice.






Jared Cole

Jared Cole

Jared Cole is a former clinical nutritionist turned journalist who now writes extensively on weight management, aging, and hormonal balance. His work has been featured in Balance Weekly, Wellness Blueprint, and Smart Health Digest.


Get Our Top Product Reviews

Our free weekly newsletter has the latest on wellness, nutrition, and product safety.




By clicking "Sign Up" I agree to the Privacy Policy and Terms of Service.




Our #1 Pick for 2025

Mitolyn

Visit Website