Drug & supplement interaction

Ilex Guayusa + Orlistat

Orlistat brand names: Xenical, Alli.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Ilex Guayusa and Orlistat in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Ilex Guayusa and Orlistat

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Orlistat and Ilex Guayusa in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Ilex Guayusa safety at a glance

Ilex Guayusa overall Use caution Generally well tolerated in tea amounts, but it contains caffeine that can cause stimulant side effects.
Pregnancy Use caution Limit or avoid because of its caffeine content and a lack of safety studies in pregnancy.
Breastfeeding Use caution Caffeine passes into breast milk, so limit intake or avoid until more is known.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Orlistat and Ilex Guayusa? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Orlistat

Interactions in our licensed database are recorded against drug classes, not just single drug names. Orlistat is filed under 2 classifications — including oral drugs. Ilex Guayusa has documented interactions with 37 drug classes — the most serious being ephedrine (major), adenosine (adenocard) (moderate) and anticoagulant/antiplatelet drugs (moderate) — and none of Orlistat’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Ilex Guayusa Does Interact With Other Medications

Ilex Guayusa has 8 major, 470 moderate, 127 minor known drug interactions in our database — Orlistat isn’t one of them. If you take anything else, check it against the full list below.

Major 8 Moderate 470 Minor 127 No known interaction 2,225 (incl. Orlistat)
Taking anything else?

Check Another of Your Medications Against Ilex Guayusa

Covers the 2,830 medications we’ve checked against Ilex Guayusa. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Ilex Guayusa and Orlistat May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Low mood Worth acting on Additional detail

    Ilex Guayusa

    “Chronic use of caffeine, especially in large amounts, may produce tolerance, habituation, and psychological dependence. There is some concern that stopping regular use of caffeine may cause withdrawal symptoms such as headache, tiredness and fatigue, decreased energy, alertness, and attentiveness, drowsiness, decreased contentedness, depressed mood, difficulty concentrating, irritability, and lack of clear-headedness…”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in anxiety.

    5 sources cited
    1. 3719. Boozer CN, Nasser JA, Heymsfield SB, et al. An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial. Int J Obes Relat Metab Disord 2001;25:316-24. PubMed
    2. 13738. Juliano LM, Griffiths RR. A critical review of caffeine withdrawal: empirical validation of symptoms and signs, incidence, severity, and associated features. Psychopharmacology (Berl) 2004;176:1-29. PubMed
    3. 2723. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
    4. 11839. Dews PB, O'Brien CP, Bergman J. Caffeine: behavioral effects of withdrawal and related issues. Food Chem Toxicol 2002;40:1257-61. PubMed
    5. 13736. Anderson BJ, Gunn TR, Holford NH, Johnson R. Caffeine overdose in a premature infant: clinical course and pharmacokinetics. Anaesth Intensive Care 1999;27:307-11. PubMed

    Orlistat

    Listed in the ADVERSE REACTIONS section of the FDA label for Orlistat. Read the label on DailyMed ›

  • Anxiety or restlessness Additional detail

    Ilex Guayusa

    “Orally, jitteriness increased in females, but not males, taking a single dose of guayusa extract in a clinical trial. The level of jitteriness reported was greater in those taking 1200 mg than those taking 600 mg. In one clinical trial, a study participant reported tremors after taking a single 650 mg dose of guayusa extract.”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in myasthenia gravis.

    2 sources cited
    1. 115148. Helwig NJ, Schwager LE, Berry AC, et al. Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization. J Int Soc Sports Nutr 2024;21(1):2379424. PubMed
    2. 113625. La Monica MB, Raub B, Ziegenfuss EJ, et al. Acute effects of naturally occurring guayusa tea and Nordic lion's mane extracts on cognitive performance. Nutrients 2023;15(24):5018. PubMed

    Orlistat

    Listed in the ADVERSE REACTIONS section of the FDA label for Orlistat. Read the label on DailyMed ›

  • Swelling Additional detail

    Ilex Guayusa

    “Some evidence shows that caffeine, a constituent of Ilex guayusa, is associated with fibrocystic breast disease, breast cancer, and endometriosis in females; however, this is controversial since findings are conflicting. Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain.”

    Ilex Guayusa · Natural Medicines adverse-effect record, reported in breast cancer.

    5 sources cited
    1. 8043. Ferrini RL, Barrett-Connor E. Caffeine intake and endogenous sex steroid levels in postmenopausal women. The Rancho Bernardo Study. Am J Epidemiol 1996:144:642-4. PubMed
    2. 8996. Horner NK, Lampe JW. Potential mechanisms of diet therapy for fibrocystic breast conditions show inadequate evidence of effectiveness. J Am Diet Assoc 2000;100:1368-80. PubMed
    3. 108806. Zheng KH, Zhu K, Wactawski-Wende J, et al. Caffeine intake from coffee and tea and invasive breast cancer incidence among postmenopausal women in the Women's Health Initiative. Int J Cancer 2021;149(12):2032-2044. PubMed
    4. 108807. Wang S, Li X, Yang Y, et al. Does coffee, tea and caffeine consumption reduce the risk of incident breast cancer? A systematic review and network meta-analysis. Public Health Nutr 2021;24(18):6377-6389. PubMed
    5. 91023. Beaudoin MS, Allen B, Mazzetti G, Sullivan PJ, Graham TE. Caffeine ingestion impairs insulin sensitivity in a dose-dependent manner in both men and women. Appl Physiol Nutr Metab. 2013;38(2):140-7. doi: 10.1139/apnm-2012-0201. Epub 2012 9. PubMed

    Orlistat

    Listed in the ADVERSE REACTIONS section of the FDA label for Orlistat. Read the label on DailyMed ›

  • Tiredness / Headache Additional detail

    Ilex Guayusa

    Recorded for Ilex Guayusa in the same Natural Medicines adverse-effect record shown under Low mood above.

    Orlistat

    Listed in the ADVERSE REACTIONS section of the FDA label for Orlistat. Read the label on DailyMed ›

Reported for Ilex Guayusa but not commonly for Orlistat: trouble concentrating, dependence or withdrawal symptoms, raised blood pressure and mood changes or irritability.

Effects for Orlistat come from the ADVERSE REACTIONS section of its FDA label; effects for Ilex Guayusa come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Overlapping uses

What Orlistat Is Prescribed For, and What Ilex Guayusa Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Orlistat is a prescription medicine with approved uses on its FDA label. Ilex Guayusa is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Orlistat is prescribed for: Orlistat helps with obesity management. That means weight loss and keeping the weight off, used together with a reduced-calorie diet. It is also used to lower the chance of regaining weight after you have lost it. Prescription Xenical and Orlistat capsules are for people with a BMI of 30 or higher, or 27 or higher if they also have risk factors such as high blood pressure, diabetes or abnormal cholesterol (dyslipidemia).

Read the rest of what Orlistat is prescribed for

Alli is an over-the-counter product for overweight adults 18 and older, used with a reduced-calorie, low-fat diet.

Ilex Guayusa has been studied for:

  • Diabetes studied, not established Ilex Guayusa has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Ilex Guayusa for diabetes

    Although there has been interest in using oral Ilex guayusa for diabetes, there is insufficient reliable information about the clinical effects of Ilex guayusa for this condition.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Orlistat on your own; if you are taking Ilex Guayusa for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

Everything else you take

See Every Supplement That Interacts With Orlistat

This page covers Ilex Guayusa only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Orlistat page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Fish Oil (moderate) and Glucomannan (moderate).

By severity: 1 major · 8 moderate · 9 minor.

From our pharmacist’s overview on the Orlistat page

“People who take Orlistat (Xenical, Alli) for weight loss often browse the very supplement aisle where fiber products and fish oil sit, and both show up on this page, so it deserves genuine attention before you mix anything in. Nearly all 18 ingredients on file can change how oral medications absorb from the gut, and the single major-ra…”

Reviewed by 2 · Jul 18, 2026

Open the Orlistat interaction page

How much people look this up

Where Ilex Guayusa and Orlistat Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Ilex Guayusa
Top half

#707 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Orlistat
Top 25%

#618 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Ilex Guayusa reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Ilex Guayusa and Orlistat records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Ilex Guayusa

What is Ilex Guayusa?

  • Energy and alertness
  • Mental focus
  • Antioxidant support
  • Appetite control
  • Athletic and physical performance

Ilex guayusa is a caffeine-containing holly leaf from the Amazon, traditionally brewed as a tea for energy and alertness, much like yerba mate or green tea. There is limited human research confirming specific health benefits, and its main reliable effect comes from its caffeine content. Because it is a stimulant, use it cautiously and check with your pharmacist or doctor if you have heart concerns or are pregnant.

Ilex guayusa · Aquifoliaceae · Leaves · Tea, brewed infusion, capsules, powdered extract, energy drinks

An interaction check asks whether these two react with each other — it does not ask whether Ilex Guayusa is a good idea for someone in your situation. Here is what our Ilex Guayusa record says about it on its own.

Ilex Guayusa: dosing

There is no official standardized dose for guayusa. It is most commonly taken as a brewed tea, and the amount of caffeine you get can vary widely depending on how much leaf you use and how long you steep it.If you use a packaged product, follow the directions on the label and do not exceed the recommended serving. Keep your total daily caffeine from all sources in mind.

From our Ilex Guayusa monograph — the full record covers uses, side effects and every documented interaction.

Read the full Ilex Guayusa monograph & all interactions
Medication

About Orlistat

What Is Orlistat Used For?

Brand names: Xenical, Alli

Orlistat helps with obesity management. That means weight loss and keeping the weight off, used together with a reduced-calorie diet. It is also used to lower the chance of regaining weight after you have lost it.

Prescription Xenical and Orlistat capsules are for people with a BMI of 30 or higher, or 27 or higher if they also have risk factors such as high blood pressure, diabetes or abnormal cholesterol (dyslipidemia). Alli is an over-the-counter product for overweight adults 18 and older, used with a reduced-calorie, low-fat diet.

See full Orlistat drug information
Keep checking

Other Drugs & Ilex Guayusa

Browse every other medication we’ve checked against Ilex Guayusa — both the ones with a known interaction and the ones without. Select any drug for the full detail.

8Major
470Moderate
127Minor
2,224No known interaction
8 Major 470 Moderate 127 Minor 2,224 No interaction
Major

8 interactions

Moderate

470 interactions

Showing 60 of 470 moderate interactions — see all 470 on the Ilex Guayusa page.

Minor

127 interactions

Showing 60 of 127 minor interactions — see all 127 on the Ilex Guayusa page.

No interaction 2,224 drugs checked — show the list

We also checked Ilex Guayusa against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,224 medications checked with no known interaction — see the full Ilex Guayusa list.

See the full Ilex Guayusa interactions page
See every supplement checked against Orlistat, ranked by severity
Evidence & sources

Ilex Guayusa References

The 90 references that drive our Ilex Guayusa monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. McEvoy GK, ed. AHFS Drug Information. Bethesda, MD: American Society of Health-System Pharmacists, 1998.
  2. Harder S, Fuhr U, Staib AH, Wolff T. Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro investigations. Am J Med 1989;87:89S-91S. PubMed
  3. Carbo M, Segura J, De la Torre R, et al. Effect of quinolones on caffeine disposition. Clin Pharmacol Ther 1989;45:234-40. PubMed
  4. Healy DP, Polk RE, Kanawati L, et al. Interaction between oral ciprofloxacin and caffeine in normal volunteers. Antimicrob Agents Chemother 1989;33:474-8. PubMed
  5. Mester R, Toren P, Mizrachi I, et al. Caffeine withdrawal increases lithium blood levels. Biol Psychiatry 1995;37:348-50. PubMed
  6. Jefferson JW. Lithium tremor and caffeine intake: two cases of drinking less and shaking more. J Clin Psychiatry 1988;49:72-3.
  7. Joeres R, Klinker H, Heusler H, et al. Influence of mexiletine on caffeine elimination. Pharmacol Ther 1987;33:163-9. PubMed
  8. Vahedi K, Domingo V, Amarenco P, Bousser MG. Ischemic stroke in a sportsman who consumed MaHuang extract and creatine monohydrate for bodybuilding. J Neurol Neurosurg Psychiatr 2000;68:112-3.
  9. Wakabayashi K, Kono S, Shinchi K, et al. Habitual coffee consumption and blood pressure: A study of self-defense officials in Japan. Eur J Epidemiol 1998;14:669-73. PubMed
  10. Hodgson JM, Puddey IB, Burke V, et al. Effects on blood pressure of drinking green and black tea. J Hypertens 1999;17:457-63. PubMed
  11. Rapuri PB, Gallagher JC, Kinyamu HK, Ryschon KL. Caffeine intake increases the rate of bone loss in elderly women and interacts with vitamin D receptor genotypes. Am J Clin Nutr 2001;74:694-700. PubMed
  12. Pollock BG, Wylie M, Stack JA, et al. Inhibition of caffeine metabolism by estrogen replacement therapy in postmenopausal women. J Clin Pharmacol 1999;39:936-40. PubMed
  13. Nurminen ML, Niittynen L, Korpela R, Vapaatalo H. Coffee, caffeine and blood pressure: a critical review. Eur J Clin Nutr 1999;53:831-9. PubMed
  14. Dews PB, Curtis GL, Hanford KJ, O'Brien CP. The frequency of caffeine withdrawal in a population-based survey and in a controlled, blinded pilot experiment. J Clin Pharmacol 1999;39:1221-32. PubMed
  15. Boozer CN, Nasser JA, Heymsfield SB, et al. An herbal supplement containing Ma Huang-Guarana for weight loss: a randomized, double-blind trial. Int J Obes Relat Metab Disord 2001;25:316-24. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Ilex Guayusa and Orlistat Together: Common Questions

Is it safe to take Ilex Guayusa with Orlistat?
We do not list a known interaction between Ilex Guayusa and Orlistat. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Ilex Guayusa and Orlistat have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Are Ilex Guayusa and Orlistat used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Ilex Guayusa in each. That is a conversation for your prescriber, especially if Orlistat is being adjusted to a target.
How was the Ilex Guayusa and Orlistat combination checked?
Interactions in our licensed database are recorded against drug classes. Orlistat is filed under 2 classifications, and Ilex Guayusa has documented interactions with 37 drug classes — none of Orlistat's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Ilex Guayusa interact with any other medications?
Yes. Ilex Guayusa has 605 documented drug interactions in our database — Orlistat is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Orlistat interact with any supplements?
Yes. Orlistat has documented interactions with 18 supplements in our database — Ilex Guayusa is not one of them. The Orlistat interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Ilex Guayusa monograph Uses, safety profile, and every drug interaction in one place Orlistat drug information The full plain-English guide to this medication Orlistat supplement interactions Every supplement checked against Orlistat, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 90 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Orlistat and Ilex Guayusa?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.