Drug & supplement interaction

Neem + Guselkumab

Guselkumab brand name: Tremfya.

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

Neem has a moderate interaction with Guselkumab. Theoretically, neem might decrease the effectiveness of immunosuppressants.

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

Neem and Guselkumab

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

Moderate

IMMUNOSUPPRESSANTS

Why this applies to Guselkumab

Guselkumab falls under IMMUNOSUPPRESSANTS — the group Neem interacts with.

Theoretically, neem might decrease the effectiveness of immunosuppressants.
Animal research suggests that neem might have immunostimulant effects.
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 basic idea with Tremfya (guselkumab): it's a monoclonal antibody that works by quieting down part of your overactive immune system to calm psoriasis or psoriatic arthritis. Neem, on the other hand, has shown signs in animal and lab studies of doing the opposite, gently revving the immune system up. So in theory, the two could work against each other, and neem might slightly blunt how well your Tremfya controls your symptoms.

I want to be honest with you though: this is theoretical only, based on early animal research, not real human cases. If neem did interfere, you might notice your plaques or joint flares creeping back. Before adding a neem supplement, just run it by your pharmacist or doctor so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Upadhyay SN, Dhawan S, Garg S, Talwar GP. Immunomodulatory effects of neem (Azadirachta indica) oil. Int J Immunopharmacol 1992;14:1187-93. 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

Neem Also Interacts With Other Medications

Neem has 1,012 moderate known drug interactions in our database — the Guselkumab one above is one of them. If you take anything else, check it against the full list below.

Moderate 1,012 No known interaction 1,818 (incl. Guselkumab)
Taking anything else?

Check Another of Your Medications Against Neem

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

Everything else you take

See Every Supplement That Interacts With Guselkumab

This page covers Neem only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guselkumab page lists 53 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Active Hexose Correlated Compound (ahcc) (moderate), Alfalfa (moderate), American Ginseng (moderate), Andrographis (moderate) and Ashwagandha (moderate).

By severity: 52 moderate · 1 minor.

From our pharmacist’s overview on the Guselkumab page

“Guselkumab (Tremfya) quiets an overactive branch of the immune system to control psoriasis and psoriatic arthritis, and all 53 supplements on this list interact the same way, by potentially revving that system back up. None is rated major, 52 are moderate and one is minor, so for most people this reads as a watch list rather than a sto…”

Reviewed by 2 · Jul 18, 2026

Open the Guselkumab interaction page

One more smart check

Taking Neem as Part of a Dietary Supplement Product? Check It for Interactions

We hold 288 real supplement products containing Neem, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Neem. Your product may carry other ingredients that interact with Guselkumab too, on top of Neem — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Neem and Guselkumab 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 Neem
Top 25%

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

29 days ago today
Medication Guselkumab
Top 10%

#208 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 Neem

What is Neem?

Neem
  • Skin conditions
  • Dental and gum health
  • Antimicrobial and antiparasitic
  • Digestive upset
  • Blood sugar support
  • Insect repellent/pesticide

Neem is a tree from India used for centuries in traditional medicine, especially for skin, dental, and antimicrobial purposes. Some small studies are promising for oral health and skin, but high-quality human evidence is limited for most uses. Neem oil and seed extracts can be toxic if swallowed, especially in children, so use with caution and talk to your pharmacist or doctor first.

Read the full Neem monograph & all interactions
Medication

About Guselkumab Injection

What Is Guselkumab Injection Used For?

Brand name: Tremfya

Tremfya (guselkumab) injection is approved to treat adults and children 6 years of age and older who weigh at least 40 kg (about 88 lbs) with moderate-to-severe plaque psoriasis or active psoriatic arthritis. It is also approved for adults with moderately to severely active ulcerative colitis or Crohn's disease.

For plaque psoriasis and psoriatic arthritis, Tremfya is an option when systemic therapy or phototherapy is appropriate. For ulcerative colitis and Crohn's disease, Tremfya is approved for adult patients only — it has not been established as safe and effective for children with those conditions.

See full Guselkumab Injection drug information
Keep checking

Other Drugs & Neem

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

0Major
1,012Moderate
0Minor
1,817No known interaction
1,012 Moderate 1,817 No interaction
Moderate

1,012 interactions

Showing 60 of 1,012 moderate interactions — see all 1,012 on the Neem page.

No interaction 1,817 drugs checked — show the list

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

Showing the 60 most looked-up of 1,817 medications checked with no known interaction — see the full Neem list.

See the full Neem interactions page
See every supplement checked against Guselkumab, 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
Neem monograph › Uses, safety, and every drug interaction in one place Guselkumab supplement interactions › Every supplement checked against Guselkumab, ranked by severity Guselkumab Injection 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 Neem and Guselkumab Together: Common Questions

Can you take Neem with Guselkumab?
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 Neem and Guselkumab 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

Still Have a Question About Guselkumab and Neem?

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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.