Drug & supplement interaction

Galacto-oligosaccharides (gos) + Tofacitinib

Tofacitinib brand names: Xeljanz, Xeljanz XR.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Galacto-oligosaccharides (gos) has a moderate interaction with Tofacitinib. Theoretically, GOS might reduce the effects of immunosuppressants.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Galacto-oligosaccharides (gos) and Tofacitinib

Here is the interaction we found between these two, with the evidence behind it.

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Tofacitinib

Tofacitinib falls under IMMUNOSUPPRESSANTS — the group Galacto-oligosaccharides (gos) interacts with.

Theoretically, GOS might reduce the effects of immunosuppressants.
Human and animal studies suggest that GOS may stimulate the immune system. This could theoretically alter the effects of immunosuppressant medications.
Severity Moderate Likelihood Possible Evidence D

Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the idea behind this one. Tofacitinib (Xeljanz) works by calming down an overactive immune system, which is exactly what you want for rheumatoid arthritis, psoriatic arthritis, or ulcerative colitis. GOS, on the other hand, is a prebiotic fiber that may give your immune system a gentle nudge in the opposite direction. So on paper, GOS could push against what tofacitinib is trying to do and slightly weaken its benefit, meaning your joint pain, swelling, or gut symptoms might creep back.

The important part: this is only a theory based on how each one behaves, not something seen happening in real patients. It's also rated as a moderate, possible concern. I wouldn't lose sleep over it, but since tofacitinib is a serious medication, just mention to your doctor or pharmacist that you'd like to try GOS so they can keep an eye on how you're feeling.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Bakker-Zierikzee AM, Tol EA, Kroes H, et al. Faecal sIgA secretion in infants fed on pre- or probiotic infant formula. Pediatr Allergy Immunol 2006;17(2):134-140. PubMed
  2. Vos AP, Haarman M, Buco A, et al. A specific prebiotic oligosaccharide mixture stimulates delayed-type hypersensitivity in a murine influenza vaccination model. Int Immunopharmacol 2006;6(8):1277-1286. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Galacto-oligosaccharides (gos) Also Interacts With Other Medications

Galacto-oligosaccharides (gos) has 120 moderate known drug interactions in our database — the Tofacitinib one above is one of them. If you take anything else, check it against the full list below.

Moderate 120 No known interaction 2,710 (incl. Tofacitinib)
Taking anything else?

Check Another of Your Medications Against Galacto-oligosaccharides (gos)

Covers the 2,830 medications we’ve checked against Galacto-oligosaccharides (gos). Pick one to open its full report.

Everything else you take

See Every Supplement That Interacts With Tofacitinib

This page covers Galacto-oligosaccharides (gos) only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tofacitinib page lists 184 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), Acacia Rigidula (moderate) and Active Hexose Correlated Compound (ahcc) (moderate).

By severity: 3 major · 143 moderate · 38 minor.

From our pharmacist’s overview on the Tofacitinib page

“Supplements deserve genuine care alongside tofacitinib (Xeljanz, Xeljanz XR), a medicine that deliberately dials down the immune system to control conditions like rheumatoid arthritis and ulcerative colitis. Most of the interactions on this page run through the liver enzymes that clear the drug, meaning an herb can push its blood level…”

Reviewed by 2 · Jul 18, 2026

Open the Tofacitinib interaction page

How much people look this up

Where Galacto-oligosaccharides (gos) and Tofacitinib 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 Galacto-oligosaccharides (gos)
Steady interest

#1,405 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Tofacitinib
Top half

#828 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.

Supplement

About Galacto-oligosaccharides (gos)

What is Galacto-oligosaccharides (gos)?

  • Prebiotic to support gut bacteria
  • Constipation
  • Digestive health
  • Immune support
  • Infant gut health

Galacto-oligosaccharides (GOS) are a type of prebiotic fiber that feed the helpful bacteria in your gut. They are generally well tolerated and may help with digestive regularity and gut balance, though they can cause gas and bloating, especially at higher doses. Evidence is promising but still limited for many uses, so talk with your pharmacist or doctor before starting.

Read the full Galacto-oligosaccharides (gos) monograph & all interactions
Medication

About Tofacitinib

What Is Tofacitinib Used For?

Brand names: Xeljanz, Xeljanz XR

  • Tofacitinib is used alone or with other medications to treat rheumatoid arthritis (condition in which the body attacks its own joints causing pain, swelling, and loss of function) in adults who are unable to take or did not respond to one or more tumor necrosis factor (TNF) inhibitor medication(s). It is also used to treat psoriatic arthritis (a condition that causes joint pain and swelling and scales on the skin) in adults who are unable to take or did not respond to or tolerate one or more TNF inhibitor medication(s). Tofacitinib is used to treat ulcerative colitis (a condition which causes swelling and sores in the lining of the colon [large intestine] and rectum) in adults who are unable to take or who did not respond to one or more TNF inhibitor medication(s). It is also used to treat polyarticular juvenile idiopathic arthritis (PJIA; a type of childhood arthritis that affects five or more joints during the first six months of the condition, causing pain, swelling, and loss of function) in children 2 years and older who are unable to take or who did not respond to one or more TNF inhibitor medication(s). Tofacitinib is in a class of medications called Janus kinase (JAK) inhibitors. It works by decreasing the activity of the immune system.

See full Tofacitinib drug information
Keep checking

Other Drugs & Galacto-oligosaccharides (gos)

Browse every other medication we’ve checked against Galacto-oligosaccharides (gos) — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
120Moderate
0Minor
2,709No known interaction
120 Moderate 2,709 No interaction
Moderate

120 interactions

Showing 60 of 120 moderate interactions — see all 120 on the Galacto-oligosaccharides (gos) page.

No interaction 2,709 drugs checked — show the list

We also checked Galacto-oligosaccharides (gos) against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,709 medications checked with no known interaction — see the full Galacto-oligosaccharides (gos) list.

See the full Galacto-oligosaccharides (gos) interactions page
See every supplement checked against Tofacitinib, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Keep exploring
Galacto-oligosaccharides (gos) monograph › Uses, safety, and every drug interaction in one place Tofacitinib supplement interactions › Every supplement checked against Tofacitinib, ranked by severity Tofacitinib drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Galacto-oligosaccharides (gos) and Tofacitinib Together: Common Questions

Can you take Galacto-oligosaccharides (gos) with Tofacitinib?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Galacto-oligosaccharides (gos) and Tofacitinib interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

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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.