Disclaimer: None of the information in this article constitutes medical advice. All statements are merely the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to prescription medication.
Alli is a weight loss pill that’s available over-the-counter (OTC) which means that it doesn’t require a prescription from a doctor. The drug is approved by the Food and Drug Administration (FDA) for weight loss, and to our knowledge is the only FDA-approved weight loss drug available OTC.
The generic name for Alli is orlistat, and we will use these terms interchangeably throughout this article as they refer to the same active drug ingredient.
In this article we’ll review the medical research on Alli to give our take on whether the medication is safe and effective for weight loss. We’ll overview the side effects of the drug, explain whether the generic version is likely to be as effective, and share a real Alli user review.
Does Alli Work?
The active ingredient in Alli has been studied in many medical trials.
One clinical trial examined whether Alli could lead to weight loss in U.S. soldiers. Over 6 months of treatment, the soldiers lost 2.87 pounds of fat mass. The soldiers weren’t obese, but they were slightly overweight.
While this trial did prove that Alli caused weight loss to a statistically significant degree, we don’t consider the results to be very impressive. Less than 0.5 pounds of fat loss per month is not worth the potential for side effects in our opinion.
A separate medical study on Alli had more impressive results. This study had a trial population of overweight and obese patients who took Alli for 24 weeks. The patients taking Alli lost 15.7% of visceral fat (fat around organs) compared to visceral fat loss of 9.4% on patients taking placebo.
Those taking Alli lost 10.25 pounds of fat overall, which is significant.
Alli has also been proven effective for patients who are only slightly overweight. A clinical trial published in the Annals of Pharmacotherapy journal tested the effects of Alli taken over 16 weeks in patients who were categorized as “mildly to moderately overweight.”
Patients in this trial were placed on a restricted calorie diet and instructed to take either Alli or a placebo pill. Both groups lost weight, but the group taking Alli lost 2.54 pounds more, which equates to a potential annuallized weight loss of 8.26 pounds on Alli.
We will conclude from the available research that Alli is effective for weight loss in patients who are slightly overweight, moderately overweight and obese, as it has been proven to work in all three types of patient populations.
How Does Alli Work?
It’s important for patients to know how their drugs function in the body.
Alli weight loss pills work by inhibiting production of certain proteins that break down fat consumed in the diet, as documented by StatPearls which is a leading database of pharmaceutical medications.
Patients taking Alli excrete more fat than they would otherwise, and the above-linked review reports that around 30% less dietary fat is absorbed on Alli than would be otherwise.
These effects are reversible, and when a patient stops taking Alli their enzyme and endogenous protein production returns to normal.
Alli Side Effects
Most side effects of Alli are relatively minor and gastrointestinal in nature, but there is a small risk of severe side effects.
The most common side effect as reported by the previously-linked StatPearls database is oily stool (medical term “steatorrhea”), but this should be expected because the way Alli works is by increasing the excretion rate of dietary fats.
A medical review of Alli noted that patients who kept dietary fat intake under 60 grams (g) daily experienced fewer GI-related side effects. It may be beneficial to even split this 60 g daily fat dose down into smaller portions to reduce side effect risk further.
For example, a patient eating three daily meals may benefit from consuming 20 g fat at each meal rather than 50 g fat at one meal and 5 g fat at the other meals.
StatPearls documents that there is a rare risk of acute kidney injury because Alli can increase oxalate production, which is deposited in the kidneys.
The FDA has also reported that Alli use is associated with a small but increased risk of severe liver injury. Only 13 out of over 40 million patients experienced this side effect.
Alli Real User Review
One of the most popular reviews of Alli from a real user is published by a channel called "The Killen Clan" and has achieved over 45,000 views at the time of updating this article.
The video appears unsponsored and the creator shares her experience using Alli for weight loss after 3 weeks:
Should I Take Alli Generic?
The generic form of Alli is called orlistat. Both of these drugs have the exact same active ingredient.
We typically recommend that patients speak with their doctor about the generic form of drugs rather than the brand-name versions, because medical research has found both drug types to be equally effective.
A medical review published in the PLOS Medicine journal compared the efficacy of generic and branded drugs, and found that there was no difference: “use of generics was associated with comparable clinical outcomes to use of brand-name products.”
Doctors may be compensated by drug companies in some cases to recommend brand-name versions of drugs, but in our opinion this does not benefit the patient.
Alli User Reviews
At the time of updating this article, Alli has been reviewed 95 times on Drugs.com, which is an online resource that allows patients to publish personal reviews of medications they're taking. The average review rating is 6/10.
The top positive review is written by a user named "Donna" who claims that, along with dietary changes, Alli has aided her weight loss efforts:
"I'm following more of a high veggie and low any type of carb diet, PLUS the Alli and I am *finally* losing those darn menopause pounds that, literally, sneak up on you. What am I saying? Take Alli to help with weight loss but if it doesn't work, you need to keep working with your Physician to get the right combination of diet & exercise for Alli to work."
The top negative review comes from a user named "FairyGardens" who claims that a new formulation of the drug has made it ineffective:
"The new generation of Orlistat, sold over the counter as Alli, does NOT work. I was on Xenical when it first came out in the 1990's. It worked very well and the orange discharge was a daily thing. Now 4 months ago I purchased Alli over the counter. Paid $85 and was very disappointed to find out that I had wasted my money."
Our Clean Weight Loss Picks
There are food-based nutrients which have been shown in medical studies to be effective for weight loss.
Dietary fiber was shown in a medical review published in The Journal of Nutrition to cause 16 pounds of weight loss in 6 months when combined with moderate caloric restriction (750 calories per day below baseline).
Supergut Fiber Mix is our recommended fiber supplement, because it contains three different types of fiber powder and no questionable additive ingredients. Interested consumers can check out Supergut Fiber Mix at this link to the product page on the brand's official website, where it retails for under $2 per serving at a subscription rate.
MCT oil is quickly absorbed by the body and increases metabolic rate, which causes fat loss. A 2015 meta-study on MCT oil documented more than one pound of weight loss over 10 weeks. This equates to potential annualized weight loss of 6 pounds per year with less than one tablespoon's worth of MCT oil per day.
Bulletproof MCT Oil is our top MCT oil product, because the only ingredient is MCT oil derived from coconuts. There are no questionable additives. Interested consumers can check out Bulletproof MCT Oil at this link to the product page on the brand's official website, where it currently costs only $15.50 for over a month's worth of product.
Coffee is one of the few whole food ingredients associated with weight loss in clinical trials. A meta-analysis published in the Nutrients journal found that coffee intake was associated with reduced body mass index (BMI) and waist circumference.
VitaCup Organic Instant Coffee Sticks is our top coffee product for weight loss, due to its convenience. No preparation or machinery is needed. The sticks can be mixed into hot or cold water (or other beverages) and consumed. The only ingredient is organic instant coffee; no questionable additives.
Interested consumers can check out VitaCup Organic Instant Coffee Sticks at this link to the product page on the brand's official website, where they retail for $1 per serving at a subscription rate.
We are not suggesting that any of the products referenced in this section are as effective as Alli, or any other FDA-approved weight loss medication. Rather, we're sharing options that patients with an aversion to pharmaceutical medication may wish to speak to their doctor about.
In 2014, Alli's manufacturer GlaxoSmithKline announced that it was recalling all Alli pills from the market due to potential tampering. The press release stated that some of the packages may have been tampered with and may contain inauthentic product.
Alli patients had reported opening the product and noting different shapes and colors of pills than that of the official product.
We haven't come across another medication that faced this issue in an Illuminate Health review.