Orlistat & Nutrient Depletion
Also searched as Xenical, Alli. What the clinical evidence reports, what it may mean, and what to discuss with your pharmacist.
Orlistat has been associated with depletion of BETA-CAROTENE, VITAMIN D, VITAMIN A and VITAMIN E and 1 more. This does not mean a deficiency will occur — it means these are worth knowing about and, if you take Orlistat long-term, worth raising with your pharmacist or healthcare provider.
Take more than one medication? Open the checker with Orlistat pre-loaded and add the rest to see overlapping nutrient signals.
Reported nutrient depletions with Orlistat
Each record below is shown as published in our licensed clinical database, with its evidence rating and citations. Expand a section for food sources and talking points.
BETA-CAROTENE
Major DepletionORLISTAT (Xenical, Alli)
Orlistat blocks the enzyme that breaks down fat for absorption. Theoretically, in addition to reducing fat absorption, it might also reduce absorption of fat-soluble vitamins like beta-carotene. Recommend that patients take a multivitamin supplement, and separate the dosing time by at least 2 hours from orlistat.
Orlistat works by blocking fat digestion in your gut, which is exactly how it helps with weight loss. The catch is that beta-carotene, a nutrient your body converts into vitamin A to support your eyes, skin, and immune system, needs fat to be absorbed properly. Because orlistat cuts fat absorption so significantly, it can pull beta-carotene out of the picture too. Given the major rating here, most long-term users are advised to take a daily multivitamin, just be sure to take it at least two hours apart from your orlistat dose so it can actually absorb. Ask your pharmacist or doctor what works best for your routine.
What Vitamin A does & food sources
Vitamin A supports vision, immune function, and skin health.
Common food sources:
- Liver and fish oils
- Dairy and eggs
- Orange and yellow vegetables (as beta-carotene)
- Leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask your provider before supplementing vitamin A — status testing is not routine, and intake from food plus multivitamins is often already adequate.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin A is fat-soluble and accumulates; excess is harmful (and dangerous in pregnancy). Prefer food sources unless a clinician advises otherwise.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Avoid high-dose vitamin A in pregnancy or when trying to conceive unless a clinician directs it.
Learn more about this nutrient: Beta-carotene — uses, safety & interactions
References (1)
- Roche Laboratories, Inc. Package insert for Xenical. April 1999.
VITAMIN D
Major DepletionORLISTAT (Xenical, Alli)
Orlistat decreases absorption of fat-soluble vitamins including vitamin D, reducing plasma levels in some patients. The manufacturer recommends that patients take a multivitamin supplement containing all fat-soluble vitamins, separating the dosing time by at least 2 hours from orlistat.
Orlistat works by blocking your gut from absorbing dietary fat, and since vitamin D is a fat-soluble nutrient, it gets caught in that same block and less of it makes it into your bloodstream. Vitamin D is something your bones, immune system, and muscles genuinely depend on, so this is considered a major concern, not a minor or theoretical one. Most people taking orlistat long-term are advised to take a multivitamin that includes vitamin D, just timed at least two hours apart from the medication so they do not interfere with each other. It is worth bringing this up with your pharmacist or doctor so they can help you figure out the right approach for your situation.
What Vitamin D does & food sources
Vitamin D helps the body absorb calcium and supports bone, muscle, and immune health.
Common food sources:
- Fatty fish (salmon, mackerel)
- Fortified milk and cereals
- Egg yolks
- Sunlight exposure (the main natural source)
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
A 25-hydroxyvitamin D blood test is the standard way to assess status — ask whether it is appropriate if you take an associated medication long-term, have limited sun exposure, or have bone concerns.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin D dosing varies a lot between people; some medications change how vitamin D is processed. Your provider can target a dose to your level instead of guessing.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin D is fat-soluble and can accumulate — very high doses over time can cause harm, so follow a clinician-guided plan.
Learn more about this nutrient: Vitamin D — uses, safety & interactions
References (3)
- Roche, Inc. Xenical package insert. Nutley, NJ. May 1999.
- McDuffie JR, Calis KA, Booth SL, et al. Effects of orlistat on fat-soluble vitamins in obese adolescents. Pharmacotherapy 2002;22:814-22.. PubMed
- Davidson MH, Hauptman J, DiGirolamo M, et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat. JAMA 1999;281:235-42. DOI
VITAMIN A
Moderate DepletionORLISTAT (Xenical, Alli)
Orlistat can decrease absorption of fat-soluble vitamins including vitamin A, leading to low plasma levels in some patients. Several studies suggest that vitamin A is not affected as much by orlistat as some other fat-soluble vitamins. However, the manufacturer of orlistat recommends that all patients take a multivitamin supplement containing all the fat-soluble vitamins, separating the dosing time by at least 2 hours from orlistat.
Orlistat works by blocking your gut from absorbing dietary fat, and unfortunately that same process can reduce how well your body takes in fat-soluble vitamins like vitamin A, which your eyes, immune system, and skin all depend on. Research suggests vitamin A tends to be less affected than some other fat-soluble vitamins with orlistat, but levels can still dip in some people over time. Because of this moderate concern, the maker of orlistat recommends taking a daily multivitamin that includes vitamin A, timed at least two hours apart from your orlistat dose. It is worth asking your pharmacist or doctor whether a multivitamin makes sense for you.
What Vitamin A does & food sources
Vitamin A supports vision, immune function, and skin health.
Common food sources:
- Liver and fish oils
- Dairy and eggs
- Orange and yellow vegetables (as beta-carotene)
- Leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Ask your provider before supplementing vitamin A — status testing is not routine, and intake from food plus multivitamins is often already adequate.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Vitamin A is fat-soluble and accumulates; excess is harmful (and dangerous in pregnancy). Prefer food sources unless a clinician advises otherwise.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Avoid high-dose vitamin A in pregnancy or when trying to conceive unless a clinician directs it.
Learn more about this nutrient: Vitamin A — uses, safety & interactions
References (5)
- Roche, Inc. Xenical package insert. Nutley, NJ. May 1999.
- Melia AT, Koss-Twardy SG, Zhi J. The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. J Clin Pharmacol 1996;36:647-53. PubMed
- McDuffie JR, Calis KA, Booth SL, et al. Effects of orlistat on fat-soluble vitamins in obese adolescents. Pharmacotherapy 2002;22:814-22.. PubMed
- Davidson MH, Hauptman J, DiGirolamo M, et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat. JAMA 1999;281:235-42. DOI
- Sjostrom L, Rissanen A, Andersen T, et al. Randomised placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients. Lancet 1998;352:167-73.. DOI
VITAMIN E
Moderate DepletionORLISTAT (Xenical, Alli)
Orlistat decreases absorption of fat-soluble vitamins including vitamin E. In most studies, vitamin E levels fall but remain within reference ranges, and only a few patients require supplements. However, the manufacturer of orlistat recommends that all patients take a multivitamin supplement containing all fat-soluble vitamins. Tell patients to separate the dose of the multivitamin by at least 2 hours from orlistat.
Orlistat works by blocking your gut from absorbing dietary fat, and since vitamin E (a nutrient your cells use as an antioxidant to protect themselves from damage) travels through the body attached to fat, less fat absorption means less vitamin E gets in too. Research shows levels do tend to dip, though they usually stay within a normal range for most people. That said, this is rated a moderate concern, so the maker of orlistat recommends taking a daily multivitamin that includes fat-soluble vitamins. Just be sure to take it at least two hours apart from your orlistat dose, and check with your pharmacist about whether a standalone vitamin E supplement makes sense for you.
What Vitamin E does & food sources
Vitamin E is a fat-soluble antioxidant that protects cell membranes.
Common food sources:
- Vegetable oils
- Nuts and seeds
- Wheat germ
- Leafy greens
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
Deficiency is rare; ask your provider before supplementing, particularly if you take blood thinners.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Higher-dose vitamin E can increase bleeding tendency, especially with warfarin or antiplatelet medications.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Discuss vitamin E supplements with your provider if you take any blood thinner.
Learn more about this nutrient: Vitamin E — uses, safety & interactions
References (5)
- Melia AT, Koss-Twardy SG, Zhi J. The effect of orlistat, an inhibitor of dietary fat absorption, on the absorption of vitamins A and E in healthy volunteers. J Clin Pharmacol 1996;36:647-53. PubMed
- Roche, Inc. Xenical package insert. Nutley, NJ. May 1999.
- McDuffie JR, Calis KA, Booth SL, et al. Effects of orlistat on fat-soluble vitamins in obese adolescents. Pharmacotherapy 2002;22:814-22.. PubMed
- Davidson MH, Hauptman J, DiGirolamo M, et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat. JAMA 1999;281:235-42. DOI
- Sjostrom L, Rissanen A, Andersen T, et al. Randomised placebo-controlled trial of orlistat for weight loss and prevention of weight regain in obese patients. Lancet 1998;352:167-73.. DOI
VITAMIN K
Moderate DepletionORLISTAT (Xenical, Alli)
Orlistat can reduce the absorption of some fat-soluble vitamins, although the extent of its effect on food-derived vitamin K hasn't been determined. In healthy people, small decreases in plasma vitamin K levels can occur, usually without any change in clotting times. However, prolonged clotting times might occur when orlistat is added to warfarin therapy. This may be due to both direct effects of orlistat on vitamin K absorption, and reduced intake of vitamin K-rich fatty foods that cause unpleasant side effects with orlistat. The manufacturer of orlistat recommends that all patients take a multivitamin supplement containing all fat-soluble vitamins, separating the dosing time by at least 2 hours from orlistat.
Orlistat works by blocking your gut from absorbing dietary fat, and because vitamin K (the nutrient your body uses to help blood clot properly) travels into the bloodstream on the back of fat, less fat absorption means less vitamin K gets through too. In most healthy people this causes only a small dip in vitamin K levels without any real clotting changes, but if you also take a blood thinner like warfarin the combination deserves closer attention. The manufacturer actually recommends a daily multivitamin covering all fat-soluble vitamins while you are on orlistat, taken at least two hours apart from the medication. If you are on orlistat long-term, it is worth a quick conversation with your pharmacist or doctor about whether a multivitamin or any monitoring makes sense for you.
What Vitamin K does & food sources
Vitamin K is required for normal blood clotting and contributes to bone health.
Common food sources:
- Leafy green vegetables (spinach, kale, broccoli)
- Vegetable oils
- Fermented foods like natto
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
What to discuss with your clinician
If you take warfarin, vitamin K intake is a central part of your therapy — consistency matters more than avoidance. Discuss any planned change in vitamin K intake (diet or supplements) with the clinic that manages your INR.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Supplement considerations
Never start or stop a vitamin K supplement on your own if you take warfarin — it directly changes how the medication works.
Do not start or stop medications or supplements without professional guidance — supplements can interact with prescription medications.
HelloPharmacist pharmacist-reviewed education — separate from the licensed record above.
Caution: Vitamin K interacts with warfarin: keep intake consistent and involve your anticoagulation clinic in any change.
Learn more about this nutrient: Vitamin K — uses, safety & interactions
References (4)
- Roche, Inc. Xenical package insert. Nutley, NJ. May 1999.
- McDuffie JR, Calis KA, Booth SL, et al. Effects of orlistat on fat-soluble vitamins in obese adolescents. Pharmacotherapy 2002;22:814-22.. PubMed
- Davidson MH, Hauptman J, DiGirolamo M, et al. Weight control and risk factor reduction in obese subjects treated for 2 years with orlistat. JAMA 1999;281:235-42. DOI
- MacWalter RS, Fraser HW, Armstrong KM. Orlistat enhances warfarin effect. Ann Pharmacother 2003;37:510-2. PubMed
This tool is educational and is not a substitute for professional medical advice. An association is not a diagnosis and does not mean a deficiency will occur. Always talk to your pharmacist or healthcare provider before starting, stopping, or changing any medication or supplement.
Disclaimer: This checker finds which nutrients might be depleted by prescription or over-the-counter medications. Each nutrient depletion issue is rated based on clinical significance. Use your own professional judgment prior to making clinical decisions.© 2026 Therapeutic Research Center Licensed records refresh weekly · last updated July 3, 2026.
More about Orlistat
What drug-induced nutrient depletion means
Some medications can, over time, lower the levels of certain vitamins, minerals, or other nutrients — through reduced absorption, increased loss, or changes in how the body uses them.
Association is not deficiency
An entry here means a depletion has been reported or studied — not that it happens to everyone, or that you are deficient. Dose, duration, diet, and your own health all matter.
Evidence varies by pair
Some drug–nutrient links (like metformin and vitamin B12) are well studied; others rest on limited or preliminary research. Each entry shows the evidence rating from our licensed clinical database.
When to ask about labs
If you take an associated medication long-term, ask your healthcare provider whether monitoring is appropriate for you. Not everyone needs testing — your provider can weigh your dose, duration, and symptoms.
Don't self-supplement blindly
Supplements are not risk-free: some can interact with medications, and some (like potassium or magnesium) can be risky with kidney disease. Talk to your pharmacist before adding anything.
Never stop a medication over this
These medications are prescribed for good reasons, and the benefit usually far outweighs a manageable nutrient consideration. Any change belongs in a conversation with your prescriber.
Food first, usually
For many nutrients, a varied diet covers the gap. Each entry lists common food sources; a supplement is a decision to make with your pharmacist or provider, not a default.
Orlistat & nutrients: FAQs
Does Orlistat deplete BETA-CAROTENE?
Should I take a supplement because I take Orlistat?
Should I stop taking Orlistat?
Where does this information come from?
Questions about Orlistat and your nutrition?
Ask a licensed pharmacist — free, no appointment needed.
Sources & How We Checked
Nutrient depletion records for Orlistat are evidence-graded and sourced from the Natural Medicines database, and are displayed as published with their citations.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference for drug-induced nutrient depletions, supplements, and interactions — the basis for this page.
- MedlinePlus, U.S. National Library of Medicine — NIH consumer drug information, used for medication overviews across the site.
Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.