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Xenical (Orlistat) Slimming Pills

Clinically proven, but some very unpleasant side effects; turning to Xenical would be our LAST resort after trying other proven fat blockers (and you need to get a doctor's consultation as it's prescription only).

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Xenical Slimming Pill Review

Visit Xenical Slimming Pill SiteXenical is a prescription medication that is clinically proven to help obese people lose weight, but the side effects are nasty. Unlike many slimming pills, Xenical is not an appetite suppressant and does not work on the brain--it works in the digestive system by blocking about 30% of the fat you ingest from being digested. Xenical attaches to lipase enzymes and prevent them from breaking down the fat, which is then passed when you go to the loo.

While Xenical is effective, the side effects are pretty disgusting, and we'd suggest trying a slightly lower-strength 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 this. Some users have even found that the over-the-counter version of Xenical, Alli (which has half the active ingredient Orlistat) has less side effects, yet still blocks and impressive 25% of fat ingested.

Xenical has been well-studied in over 100 trials of up to four years' duration, so its effects are well known. One study showed that 69% of people taking Xenical lost an average of 13 pounds after three months, and 19 pounds after a year. Another study showed that taking Xenical with a reduced calorie diet over a year led to an average weight loss of approximately 13.4 pounds, compared to 5.8 pounds on diet alone. Yet another study showed an average loss of 5-10% of body weight in one year. Typically, most people begin losing weight within two weeks of starting Xenical and continue losing for 6 to 12 months, at which point losses start to trail off.

You take one 120g 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. There are many conditions and medications which are not compatible with Xenical, so it's important to consult your doctor before getting this prescription medication (it is one of only two prescription weight loss drugs available in the UK, the other being Reductil).

Xenical 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 30% of the fat you eat will be undigested, you should expect your bowel movements to change--often to a more orange colour. Xenical is notorious for its side effects: according to clinical study language, 22% of patients experience "faecal urgency or incontinence," 23% experience "gas with faecal discharge," and 20% experience "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 more likely to 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 nasty consequences (!!!)

There are some concerns that Xenical could cause liver damage, and the matter is currently under investigation by the FDA. The manufacturer has publicly responded that Xenical 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 Xenical 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: As Xenical is a prescription medication and illegal to purchase in the UK over the counter or over the internet, we don't provide purchase links or prices. However, for comparison only, a one-month supply costs around £115.


Common Misspellings: Xenicel, Zenical, Zenacal, Xinical, and Zanacal

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Key Facts

Xenical Diet Service Logo

• Clinically proven
• Will cut fat absorption by 30%
• Will almost certainly lead to weight loss

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

Price: Prescription only--international prices around £115

Philosophy: Fat Blocker

Clinical Trials: 100+


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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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