How Alli Works

Alli is a drug created for treating obesity. It was developed later than similar medications but Alli the first drug for the obesity treatment which acts only in the gastrointestinal tract. It’s been approved for use in the USA since 1999.

Alli is the first weight loss medicine that doesn’t work systematically. Alli’s effective in the gastrointestinal tract only.

Alli blocking fat. It inhibits gastric and pancreatic lipases that prevents absorption of approximately 30% of dietary fats. It belongs to the group of pentanoic acid esters and forms covalent bonds with the active sites of serine residues in gastric and pancreatic lipases by inhibiting their activity and preventing the absorption of approximately 30% of fats our body gets from food. Weight loss effect from Alli caused by two factors: a decrease in intake of fat and development of side effects – unpleasant sensations in the stomach when taking fatty food that causes the patient to limit fatty food.

When you are following a 2000 calories diet plan made up of 30% fat, Alli blocks the digestion of 22 grams of fat which equals the intake of 200 kcal a day. This helps you to eat 6000 less calories a month and reduce your body weight by nearly 900g. The second treatment factor motivates you to change your diet plan. When used properly, this medication can reduce your body weight even if the initial change in lifestyle proved to be ineffective.

How Alli Works

The effectiveness of Alli in treating obesity has been proved by several randomized, placebo-controlled clinical trials each lasting for 1-2 years. Alli side effects were studied in two placebo-controlled trials. Patients were taking 120 mg Alli 3 times a day. At first, all participants were following a low-calorie diet plan for 1 year. After that, they started to take either Alli or placebo for another year. The research results were similar. The average weight loss was 10% when treated with Alli and 6% when treated with placebo. During the following year, patients who continued taking Alli increased their body weight by 1.5-3 kg and patients who kept taking placebo gained 4-6 kg (this body weight was close to the original). Besides, Alli has shown a positive change in the contents of total cholesterol, LDL, glucose, insulin and blood pressure levels. This drug was revealed to have a unique property. It affected the concentration of lipids in serum by inhibiting the absorption of fat in the digestive tract. Alli can be used for the correction of lipid levels.

Another study involved patients who suffered from both obesity and type 2 diabetes and were treated with sulfonylurea drugs. As statistics shows, Alli has significantly improved the plasma glucose levels and reduced the hemoglobin A1c, and lipids in the blood. It also helped to reduce the dose of sulfonylurea.

For patient compliance with the treatment it is very important to control the severity of side effects. All patients who didn’t control the consumption of fats in their diet plan had a problem with oily loose stools. In about 20-40% cases Xenical caused other side effects in the gastrointestinal tract, including frequent defecation, bloating, intense flatus, soiled clothes, peremptory urging to stool, and fecal incontinence. Thus it is very important to explain patients the rules of taking this drug and the importance of reducing the dietary fat content.

The most significant concerns of Xenical therapy are big chances of malabsorption of fat-soluble vitamins A, D, E, K, B-carotene and other carotenoids. Indeed, Alli treatment decreased the amount of these substances in the plasma compared to placebo treatment. Still it remained within normal limits. Nonetheless, manufacturers recommend that all patients who take Xenical should also take multivitamins with B-carotene and fat-soluble vitamins 2 hours before or after taking Xenical.

Doctors usually prescribe their patients to take Alli 120mg (1 capsule) 3 times a day during fat meals. It is allowed to take the drug during or within 1 hour after a meal.

There is one more precaution that concerns Alli treatment. The caloric value of food is determined by 4 groups of substances: fats, carbohydrates, proteins, and alcohol. Alli partly prevents the absorption of only one of them. If a patient increases the intake of other substances instead of fats, the total caloric value of a diet plan also increases along with body weight. In order to make Xenical treatment effective, it is necessary to pay attention at your diet plan and reduce its total caloric value.

Alli side effects

• Stomach discomfort
• Increased number of bowel movements
• Loss of control of bowel movements
• Urgent need to go to the bathroom
• Gas with release of stool
• Oily/fatty stools
• Oily discharge
• Clear, orange or brown colored bowel movements

How Effective is Alli

For example: if you observe the 2000 calorie diet, which contains 30% fat, orlistat will block the digestion of approximately 22 grams of fat that is 200 calories per day.

At this rate, one month of treatment, the total caloric of your food is reduced by 6000 calories, which will reduce weight by nearly 2.2 lbs, or nearly 25 lbs per year of treatment.

Xenical vs Alli

Xenical and Alli contain the same active ingredient (orlistat), but they are not identical. The drugs have different indications and dosage. Xenical is manufactured by Roche, contains 120 mg of orlistat and prescribed by doctors for people with a body mass index (BMI) greater than or equal to 30, or greater than 28, which is associated with risk factors. Alli contains 60 mg of orlistat and is licensed in the EU and the US, as OTC diet pills for adults with a BMI equal to or higher than 25 who hold a low-calorie diet with low fat diet.

Xenical at 15% More Effective than Alli. Traditionally, Orlistat was available in one 120 mg dose and sold under the brand name Xenical. It was produced by Roche and sold by prescription only since 1999.

The American company GlaxoSmithKline Consumer Healthcare presented the results of their own research in 2007 assuring that their version of Orlistat (Alli) available in 60 mg doses was only 15 percent less effective than Xenical. In other words, Alli 60 mg capsules provided roughly 85 percent of Xenical 120 mg dose effectiveness. Source:

Besides, the reduction of dosage, in theory, helps to reduce the frequency of side effects.

Generic Xenical

Alli is a generic of Xenical that is a medication contains Orlistat, but its capsules have a different name on them (not Xenical) which depends on the country of the generic drug production. To date, we know of at least three different generic Orlistat brands:

1. Xenical, produced by the Swiss company Roche since 1999.
2. Alli, produced by the American company GlaxoSmithKline since 2007.
3. Orsoten, produced by the Slovenian company Krka since 2009.
4. Obelit produced by Indian manufactures.

How Effective is Generic Orlistat

The main purpose of clinical trials that were conducted in Russia in 2009 was to compare the effectiveness of generic Orlistat and original brand Xenical that was more familiar to obese patients.

Krka, the leading generic company from Slovenia, spent 12 weeks studying the difference between Xenical produced by the Swiss company Roche and Krka’s own brand Orsoten, each pill of which contained 120 mg of Orlistat, the chemical substance that was included in Xenical produced by the Swiss company and Alli produced by the American company GlaxoSmithKline.168 patients (both men and women 18+ years old) were divided into two equal groups: Xenical group and Orlistat group. Their weight reduction results are shown in the table below:

Brand Xenical vs Generic Orlistat – Clinical Trial on 169 Patients
Weight Reduction Generic Orlistat

Xenical Brand

Less 5% 44 (52,4%) 41 (48,8%)
From 5% to 10% 34 (40,5%) 38 (45,2%)
More 10% 6 (7,1%) 5 (5,9%)
As the table shows, the results of these clinical trials have proved that generic Orlistat is nearly as effective as original Xenical.

Buying Xenical or Alli

The Food and Drug Administration has approved only 2 versions of Orlistat for online sales in the U.S.:

1. Xenical 120 mg capsules sold by prescription only.
2. Alli 60 mg pills sold without a prescription (over-the-counter).

The only difference because of which buying Xenical require a prescription, but Alli is over-the-counter – is due dosage form of each tablet.

Alli is Smaller no Prescription Version of Xenical. Alli is also known as half-reduced form of Xenical.