> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hi-doctor.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Orlistat 120mg

> How orlistat (Xenical) blocks fat digestion, the XENDOS trial results, and the gastrointestinal side effects it is known for.

Orlistat is a capsule you swallow with meals. It is not a hormone and does not
act on the brain or on appetite: it blocks the gut enzymes that digest fat, so
roughly a third of the fat in a meal leaves the body in the stool instead of
being absorbed. In the EU it is sold as **Xenical** and is taken alongside a
slightly reduced-calorie, lower-fat diet.

<Info>
  **Active ingredient** orlistat  ·  **Dosages** 120 mg with each main
  meal  ·  **Authorised in the EU** since 29 July 1998
</Info>

## What it is

Orlistat is a lipase inhibitor: it blocks the intestinal enzyme that digests
fat, reducing the absorption of part of the fat you eat. Unlike GLP-1s, it
does not act on appetite — its effect depends on keeping to an appropriate diet
while taking it. It's a valid alternative for people who cannot or do not want
injectables, although average weight loss is usually lower.

## How it works

<CardGroup cols={3}>
  <Card title="It switches off fat-digesting enzymes" icon="lock">
    Orlistat binds to lipases, the enzymes your stomach and small intestine
    release to digest fat. It forms a chemical bond with the active site of
    gastric and pancreatic lipase and switches the enzyme off inside the gut.
    It is not an appetite medicine and does not act on the brain.
  </Card>

  <Card title="Dietary fat stays undigested" icon="droplet">
    The inactivated enzyme cannot break dietary fat, which arrives as
    triglycerides, into the smaller free fatty acids and monoglycerides that
    the gut wall is able to take up. The fat therefore stays whole, and whole
    fat molecules are too large to cross into the body.
  </Card>

  <Card title="The blocked fat leaves in stool" icon="route">
    The unabsorbed fat passes along the bowel and out in the stool, so those
    calories never reach you. The EMA describes the 120 mg dose as letting
    about 30% of the fat eaten in a meal pass through undigested.
  </Card>
</CardGroup>

<CardGroup cols={3}>
  <Card title="No injections" icon="pills">
    Taken as a hard capsule; it acts only inside the gut.
  </Card>

  <Card title="Local, not systemic" icon="stomach">
    Acts locally in the gut, not system-wide.
  </Card>

  <Card title="Adjunct to diet" icon="apple-whole">
    An alternative when GLP-1s aren't the right fit.
  </Card>
</CardGroup>

## What the studies reported

**XENDOS** (*Diabetes Care* 2004;27(1):155-161) was designed to test
prevention of type 2 diabetes rather than weight loss alone. Only 52% of the
orlistat group and 34% of the placebo group completed the four years, and
everyone in the trial also made lifestyle changes. The **European Multicentre
Orlistat Study** (*Lancet* 1998;352(9123):167-172) is the other cited trial.
Full prescribing detail is in the EMA EPAR for Xenical and its Summary of
Product Characteristics (SmPC).

## Interactions

Because orlistat blocks fat absorption, it can interfere with the absorption
of other medicines taken at the same time. The EU Summary of Product
Characteristics advises that orlistat and cyclosporine should not be taken
together, and that thyroid medicines, warfarin and some anti-epileptic
medicines may need dose adjustment. The reviewing doctor checks current
medication before prescribing.

## What happens when you stop

Because orlistat works only while it is in the gut, stopping means normal fat
digestion resumes. Weight that was lost during treatment can be regained if
the dietary changes made alongside it are not sustained. The reviewing doctor
discusses a maintenance plan when treatment ends.

## Common questions

<AccordionGroup>
  <Accordion title="Can I take orlistat alongside a GLP-1 medicine?">
    Orlistat and GLP-1 medicines work through completely different mechanisms
    — one in the gut, one through hormone signalling. A doctor reviews whether
    combining them is appropriate for your case, but the two are not routinely
    prescribed together.
  </Accordion>

  <Accordion title="How long until I see results with orlistat?">
    The effect on fat absorption starts with the first capsule taken with a
    fatty meal. Weight change is reviewed by the doctor at month 3, the first
    meaningful assessment point.
  </Accordion>

  <Accordion title="Do I need to change my diet when taking orlistat?">
    Yes. Orlistat is authorised alongside a mildly reduced-calorie, lower-fat
    diet. Bowel side effects are more likely after a fatty meal, so adjusting
    meals towards lower fat from day 1 is part of the approach.
  </Accordion>

  <Accordion title="Can I take a multivitamin with orlistat?">
    Orlistat can reduce absorption of vitamins A, D, E and K. The EU product
    information advises a diet rich in fruit and vegetables and says a
    multivitamin supplement taken at bedtime may be considered.
  </Accordion>

  <Accordion title="Is orlistat safe for long-term use?">
    Orlistat has been authorised for use in the EU since 29 July 1998, with
    long-term safety data from the XENDOS trial that followed people for four
    years. The doctor reviews response at month 3 and periodically thereafter.
  </Accordion>
</AccordionGroup>

## What has been reported

<Accordion title="Side effects, from the EU Summary of Product Characteristics">
  | Effect                                                                                        | Frequency                       |
  | --------------------------------------------------------------------------------------------- | ------------------------------- |
  | Oily spotting from the rectum, fatty/oily stools, wind with discharge, urgent bowel movements | Very common (more than 1 in 10) |
  | Abdominal pain or discomfort, flatulence, liquid stools                                       | Very common (more than 1 in 10) |
  | Headache                                                                                      | Very common (more than 1 in 10) |
  | Faecal incontinence, soft stools                                                              | Common (1 in 100 to 1 in 10)    |
</Accordion>

**Lower absorption of fat-soluble vitamins.** Orlistat can reduce absorption of
vitamins A, D, E and K; the EU product information advises a diet rich in
fruit and vegetables and says a multivitamin supplement, taken at bedtime, may
be considered.

<Warning>
  Oily stools are very common. Yellowing skin can signal serious liver injury and
  needs urgent medical attention.
</Warning>

## How to take it

<Steps>
  <Step title="Days 1–7">
    Adjust meals towards lower fat.
  </Step>

  <Step title="Weeks 2–8">
    Consistent use with each main meal.
  </Step>

  <Step title="Month 3">
    Response reviewed by your doctor.
  </Step>
</Steps>

Take it with the meal — one 120 mg capsule with each main meal, up to three
capsules a day. Skip meals that have no fat, since there is nothing for it to
act on.

## How Hi-Doctor handles it

An EU-licensed doctor reviews your case and, if eligible, issues an electronic
prescription valid at any EU pharmacy under Directive 2011/24/EU. See
[pricing](/essentials/pricing) for the consultation fee; the medicine is paid
separately at a pharmacy. For injectable alternatives, see
[liraglutide](/library/medicines/liraglutide),
[semaglutide](/library/medicines/semaglutide), or
[tirzepatide](/library/medicines/tirzepatide). For the non-prescription version,
see [alli](/library/medicines/alli). The full eligibility checks are on
[safety](/essentials/safety) and the [weight-loss treatment
area](/essentials/treatments).

## Start a consultation

<Card title="Weight-loss consultation" icon="stethoscope" href="https://hi-doctor.ai/consultation/weight-loss/1">
  Answer the weight-loss questionnaire and a registered doctor reviews it.
  They decide whether treatment is appropriate, which one, and at what dose —
  and declining is a normal outcome. See [what it costs](/essentials/pricing)
  and [how the review works](/essentials/how-it-works).
</Card>

<Warning>
  This page is reference information, not medical advice and not a prescription.
  Whether a medicine is appropriate for you is decided by a registered doctor
  after reviewing your consultation.
</Warning>