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A proven (though pricey) fat blocker, if you can stand the disgusting and messy "treatment effects"...

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Alli Slimming Pill Review

AlliAlli is a proven fat blocker that has taken the dieting world by storm since its 2007 introduction; it is effective if you can stomach the nasty side effects, but there are some excellent alternatives available instead. Alli contains half the dosage of the active ingredient Orlistat that is found in the prescription obesity treatment Xenical, but the great thing is Alli still blocks 25% of dietary fat compared to Xenical's 30%, so you're really not missing that much by going with the cheaper Alli. Also, some users have reported considerably less nasty side effects compared with the prescription-strength version.

Even so, we'd suggest trying a less harsh fat blocker like Proactol (around 28% effective at blocking fat with few side effects according to studies) or Lipobind (allegedly 27% effective) before turning to Alli or Xenical.

Unlike many slimming pills, Alli is not an appetite suppressant and does not work on the brain--it works in the digestive system by blocking about 25% of the fat you ingest from being digested. Alli attaches to lipase enzymes and prevent them from breaking down the fat, which instead of being absorbed into the body is passed when you go to the loo.

You take one 60g capsule with liquid at each main meal that contains fat--up to three times a day. You can take the pill up to an hour afterwards and still get the desired effect. You should eat a sensible diet, consisting of about 30% of calories from fat. As the pill only works in the presence of fat, if you eat say a cereal breakfast with skim milk that has very little fat, then there's no need to take it for that meal.

Xenical was the first lipase inhibitor approved by the US Food and Drug Administration in 1999, and reduced strength over-the-counter Alli version hit the market in 2007. There are many conditions and medications which are not compatible with Alli, so you should consult your doctor before getting this medication.

Alli is only recommended for those with a BMI of 30 or above, or with a BMI of 27 and other risk factors such as high blood pressure, cholesterol, heart disease, or diabetes.


Side Effects: As 25% of the fat you eat will be undigested, you should expect your bowl movements to change--often to a more orange colour. Alli is notorious for its various side effects which many users experience: according to clinical study language, "faecal urgency or incontinence gas with faecal discharge, fatty or oily stools." In fact, these nasty side effects are described as "treatment effects" in the literature and this "aversion therapy," is part of the drug's effectiveness. It encourages the user to associate eating fat with unpleasant side effects and therefore stick to a low fat diet. The drug’s maker, GlaxoSmithKline, has been up front about the pill’s side effects, suggesting that new users wear dark pants or bring a change of clothes to work until they get used to the diet pill’s potentially messy consequences (!!!)

There are some concerns that Alli could cause liver damage, and the matter is currently under investigation by the FDA. The manufacturer has publicly responded that the active ingredient in Alli, Orlistat, is the most highly tested weight loss drug in history, with over 100 clinical trials and 30,000 patients, which did not reveal liver damage as a side effect.

Because Alli interferes with the body's absorption of some fat soluble vitamins, you should take a daily multivitamin supplement at bedtime that contains vitamins D, E, and K and beta carotene.


Prices: Alli can be purchased over the counter at chemists and such, but you can almost always get a better deal online; it costs around £36 for 84 pills (essentially a one-month supply).


Common Misspellings: Ally, Alle, Allie


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Key Facts

Alli Diet Service Logo

• Clinically proven with 100+ studies
• Will cut fat absorption by 25%
• Will almost certainly lead to weight loss

• two words: "fecal incontinence"
• Slow weight loss
• High cost

Price: around £36 for month's supply

Philosophy: Fat Blocker

Clinical Trials: 100+




The information on is intended to promote weight loss and weight maintenance, and does not offer medical advice. If you have, or believe you have, a medical condition you should consult your doctor before starting a weight loss, slimming pill, or exercise programme. is not intended to be used as reference for pregnant or breast-feeding women, people with medical conditions, or anyone under age 18. New diets or weight loss supplements should be attempted only after consulation with your GP.

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