Drug & supplement interaction

Selenium + Niacin, Simvastatin

Niacin, Simvastatin brand name: Simcor.

Minor Interaction
Medically reviewed by · Updated October 2026
The bottom line Minor

Selenium has a minor interaction with Niacin, Simvastatin. Selenium might reduce the beneficial effects of niacin on high-density lipoprotein (HDL) levels.

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

Selenium and Niacin, Simvastatin

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

Minor

NIACIN

Selenium might reduce the beneficial effects of niacin on high-density lipoprotein (HDL) levels.
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease. It is not known whether this adverse effect is due to a single antioxidant such as selenium, or to the combination. It also is not known whether it will occur in other patient populations.
Severity Minor Likelihood Possible Evidence A

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 gist with Simcor (niacin plus simvastatin): one big reason people take niacin alongside a statin is to nudge up their HDL, the so-called "good" cholesterol. In a well-run clinical trial, folks who took a mix of antioxidants (including selenium, along with vitamins C and E and beta-carotene) saw that helpful HDL boost cut by more than half. So selenium may quietly work against one of the benefits you're hoping for.

The good news: this is rated a minor interaction, and it isn't clear whether selenium alone causes it or only the full antioxidant combo. Everyday food amounts of selenium are unlikely to be the issue, but a concentrated supplement might. Before adding selenium, just run it by your pharmacist or doctor so they can check your cholesterol goals.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Brown BG, Zhao XQ, Chait A, et al. Simvastatin and niacin, antioxidant vitamins, or the combination for the prevention of coronary disease. N Engl J Med 2001;345:1583-93. DOI
  2. Cheung MC, Zhao XQ, Chait A, et al. Antioxidant supplements block the response of HDL to simvastatin-niacin therapy in patients with coronary artery disease and low HDL. Arterioscler Thromb Vasc Biol 2001;21:1320-6. 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

Selenium Also Interacts With Other Medications

Selenium has 288 moderate, 32 minor known drug interactions in our database — the Niacin, Simvastatin one above is one of them. If you take anything else, check it against the full list below.

Moderate 288 Minor 32 No known interaction 2,510 (incl. Niacin, Simvastatin)
Taking anything else?

Check Another of Your Medications Against Selenium

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

From our Q&A

Questions About Selenium or Niacin, Simvastatin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Selenium or Niacin, Simvastatin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Niacin, Simvastatin

This page covers Selenium only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Niacin, Simvastatin page lists 187 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Beer (major), Grapefruit (major) and Siberian Cocklebur (major).

By severity: 8 major · 140 moderate · 39 minor.

From our pharmacist’s overview on the Niacin, Simvastatin page

“Simcor combines niacin with simvastatin to lower cholesterol, and its interaction list deserves genuine care. Simvastatin is cleared by the CYP3A4 enzyme, and well over a hundred of these ingredients can push its blood level up or drag it down through that pathway.”

Reviewed by 2 · Jul 18, 2026

Open the Niacin, Simvastatin interaction page

One more smart check

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

We hold 16,942 real supplement products containing Selenium, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Selenium. Your product may carry other ingredients that interact with Niacin, Simvastatin too, on top of Selenium — 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 Selenium and Niacin, Simvastatin 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 Selenium
Top 1%

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

29 days ago today
Medication Niacin, Simvastatin
Steady interest

#1,536 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 Selenium

What is Selenium?

  • Thyroid health support
  • Antioxidant support
  • Immune support
  • General nutrient supplementation
  • Reproductive/fertility support

Selenium is an essential trace mineral your body needs in small amounts for thyroid function, antioxidant defense, and immune health. Most people who eat a varied diet get enough, and supplements are mainly useful for those who are deficient. Because too much selenium can be toxic, stick to recommended amounts and check with your pharmacist or doctor before supplementing.

Read the full Selenium monograph & all interactions
Keep checking

Other Drugs & Selenium

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

0Major
288Moderate
32Minor
2,509No known interaction
288 Moderate 32 Minor 2,509 No interaction
Moderate

288 interactions

Showing 60 of 288 moderate interactions — see all 288 on the Selenium page.

Minor

32 interactions

No interaction 2,509 drugs checked — show the list

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

Showing the 60 most looked-up of 2,509 medications checked with no known interaction — see the full Selenium list.

See the full Selenium interactions page
See every supplement checked against Niacin, Simvastatin, 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
Selenium monograph › Uses, safety, and every drug interaction in one place Niacin, Simvastatin supplement interactions › Every supplement checked against Niacin, Simvastatin, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Selenium and Niacin, Simvastatin Together: Common Questions

Can you take Selenium with Niacin, Simvastatin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Selenium and Niacin, Simvastatin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Niacin, Simvastatin and Selenium?

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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.