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 an FDA- approved 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 the only OTC weight loss medication in the US at the time of updating this article.
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.
But is Alli proven in research studies to cause weight loss? And if so, how much weight loss is possible? Does Alli cause side effects? And how do real Alli users rate and describe the effects of the drug?
In this article we’ll answer all of these questions and more, as we review clinical studies on Alli to determine if the drug is effective for weight loss, and if so, how much weight loss it's shown to cause.
We'll discuss side effects, feature unsponsored customer reviews, and explain where to buy Alli for the best price.
We'll also share our thoughts on whether the generic version of Alli is a better option, and explain why Alli was recalled from the market in 2014.
Does Alli Cause Weight Loss?
Alli has been studied in many clinical trials for its effects on weight in overweight and obese individuals.
A 2012 clinical trial examined Alli's effects on weight in US soldiers. Over six months of treatment, the soldiers lost 2.87 pounds of fat mass. The soldiers weren’t obese at baseline, but they were slightly overweight.
A separate 2012 clinical trial on Alli reported more impressive results.
Participants in this trial were overweight and obese, and took Alli for 24 weeks. Those taking Alli lost 15.7% of visceral fat (fat around organs), compared to visceral fat loss of 9.4% in patients taking placebo pills.
Those taking Alli in the above-linked trial lost 10.25 pounds of fat overall, which is significant.
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 shown to work in all three patient populations.
Does Alli Cause Side Effects?
Alli does cause side effects in some patients.
The most common side effect is oily stool (medical term “steatorrhea”), according to a 2022 medical review, but this should be expected because the way Alli works is by increasing the excretion rate of dietary fats.
A medical review published in the Expert Opinion on Pharmacotherapy journal noted that patients who kept dietary fat intake under 60 grams (g) daily experienced fewer gastrointestinal side effects.
It may be beneficial to split this 60 g daily fat dose down into smaller portions to reduce side effect risk further.
For example, someone taking Alli who eats three daily meals may benefit from consuming 20 g of fat at each meal, rather than 50 g of fat at one meal and 5 g of fat in the other two meals.
The above-linked 2022 medical review documents that Alli use is associated with 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.
Real People Try Alli
A YouTube creator named "The Circuses" shares her experience after using Alli for three weeks, in a video with over 50,000 views:
A TikTok creator named "abigailrussel" claims that Alli caused 50 pounds of weight loss, and shares a before-and-after image:
@abigailrussell Reply to @kokobbyyy #greenscreen #weightlossjourney #weightlossprogress #alli #orllistat ♬ Steven Universe - L.Dre
Where to Get the Best Price
Alli is sold at a variety of online retailers. Here's a price breakdown for a one-time purchase of a 120-count bottle at the time of updating this article:
Rite Aid: $80.99 (free shipping, link)
Walgreens: $79.99 (free shipping, link)
Walmart: $70 (free shipping, link)
Amazon: $70 (free shipping, link to official Amazon listing)
Alli is currently 14% cheaper at Amazon and Walmart than at Rite Aid.
Patients Rate Alli
Drugs.com is a website where patients taking prescription medication can publish reviews sharing their experience.
We cannot verify the accuracy or authenticity of any reviews on this site.
Alli has been reviewed 100 times on Drugs.com at the time of updating this article, with an average review rating of 6 out of 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."
Should I Take the Generic Version?
As referenced in the intro to this article, the generic form of Alli is called orlistat.
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 shown 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.”
While generic drugs are usually considerably cheaper, this is not the case with Alli.
Alli currently costs around $70, while generic orlistat has a retail price over $500 at the time of updating this article, according to GoodRx.
The above-linked version of orlistat does have a higher dose than Alli, but not enough to offset the price differential.
Why Was Alli Recalled?
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 they were used to.
We haven't come across another medication that faced this issue in an Illuminate Health review.
At the time of updating this article, we haven't come across any information suggesting this is an ongoing issue.
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 in the 2022 medical review cited in the side effects section of this article.
Patients taking Alli excrete more fat than they would otherwise, and 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.
Our Clean Weight Loss Picks
Ceylon cinnamon was described as "an effective anti-obesity agent" in a 2022 meta-analysis. The study authors concluded that effects were greater at doses at or over 3 grams daily.
Illuminate Labs Ceylon Cinnamon Extract is our standardized Ceylon cinnamon supplement which is third-party tested to ensure purity and potency.
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).
MBG Organic Fiber Potency+ is our top fiber pick because it's certified organic, provides 7 g of fiber per serving and costs under $1.85 per serving at the time of updating this article.
Both of the products mentioned in this section are entirely free of additive ingredients that we consider to be unhealthy.
We are not suggesting that 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.
Pros and Cons of Alli
Here are the pros and cons of Alli in our opinion:
Pros:
- Available OTC
- Reasonable retail prices
- Clinically proven to work
- Milder side effect profile than some weight loss drugs
- Currently cheaper than generic version
Cons:
- May cause oily stool
- Shown to cause liver damage in very small minority of users
- Drug tampering issue in 2014
