Drug & supplement interaction

Danshen + Niacin, Simvastatin

Niacin, Simvastatin brand name: Simcor.

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

Niacin, Simvastatin falls into 2 drug categories that Danshen can interact with; the most serious is rated moderate. Danshen might alter the levels and clinical effects of drugs metabolized by CYP3A4.

Read the full interaction report
SeverityModerate
LikelihoodPossible
Interactions2
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Danshen and Niacin, Simvastatin

These two interact in 2 distinct ways. Each one is explained separately below.

Why Are There 2 Interactions?

Danshen interacts with whole categories of medication. Niacin, Simvastatin falls into 2 of those categories, so it can interact with Danshen in 2 different ways. We’ve listed each one below — your overall risk is driven by the most serious of them (Moderate).

Moderate

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES

1 of 2

Why this applies to Niacin, Simvastatin

Niacin, Simvastatin falls under CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES — the group Danshen interacts with.

Danshen might alter the levels and clinical effects of drugs metabolized by CYP3A4.
Preliminary clinical research in healthy males shows that the administration of danshen for 10-14 days induces intestinal CYP3A4 and increases the clearance of midazolam, a CYP3A4 substrate. The maximum concentration of midazolam was decreased by 31% to 67%, and drug levels were decreased by 27% to 80%. However, a single dose of danshen has the opposite effect, increasing maximum concentrations of midazolam by 87%.
Severity Moderate Likelihood Possible Evidence B

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

The simvastatin portion of Simcor is cleared by an enzyme in your gut and liver called CYP3A4. Here's the tricky part with Danshen: when taken regularly for a week or two, it tends to speed up that enzyme, which could lower your simvastatin levels and make it less effective at controlling your cholesterol. But a single dose seems to do the opposite, briefly raising simvastatin levels, which can bump up the risk of muscle aches or, rarely, more serious muscle problems.

The niacin part isn't really affected this way. This is based on small early studies, so it's not a sure thing, but it's worth a quick chat with your pharmacist or doctor before mixing the two so they can keep an eye on things.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Qiu F, Wang G, Zhang R, Sun J, et al. Effect of danshen extract on the activity of CYP3A4 in healthy volunteers. Br J Clin Pharmacol 2010;69:656-62. PubMed
  2. Qiu F, Jiang J, Ma Y, Wang G, Gao C, Zhang X, Zhang L, Liu S, He M, Zhu L, Ye Y, Li Q, Miao P. Opposite Effects of Single-Dose and Multidose Administration of the Ethanol Extract of Danshen on CYP3A in Healthy Volunteers. Evid Based Complement Alternat Me PubMed
Moderate

GLUCURONIDATED DRUGS

2 of 2

Niacin, Simvastatin also falls under GLUCURONIDATED DRUGS.

Theoretically, danshen might affect the levels and clinical effects of drugs requiring glucuronidation.
In vitro research shows that danshen induces the expression of glucuronosyltransferases. However, it also inhibits the activity of glucuronosyltransferases, including various members of the 1A and 2B families. The extent of inhibition of a specific glucuronosyltransferase seems to be dependent on whether or not the danshen is processed via 'sweating'. This type of processing may affect the levels of constituents in danshen that alter glucuronosyltransferase activity. So far, this interaction has not been reported in humans.
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 honest picture with Simcor, which combines niacin and simvastatin. Danshen has been shown in lab dishes to mess with glucuronidation, a process your body uses to package up and clear certain drugs (including niacin). In theory, if Danshen slows that down, niacin could build up a bit, which might mean more flushing, itching, an upset stomach, or changes in liver enzymes. But Danshen also seems to speed that same process up in other experiments, so the direction isn't even consistent.

The big caveat: this has never actually been reported in people so far, only in test tubes and animals. So I wouldn't lose sleep over it. Still, since Danshen can also thin the blood, it's worth a quick chat with your pharmacist or doctor before combining them.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Liu J, Shi Y, Wu C, et al. Comparison of sweated and non-sweated ethanol extracts of Salvia miltiorrhiza Bge. (Danshen) effects on human and rat hepatic UDP-glucuronosyltransferase and preclinic herb-drug interaction potential evaluation. Curr Drug Metab

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

Danshen Also Interacts With Other Medications

Danshen has 123 major, 935 moderate known drug interactions in our database — the Niacin, Simvastatin one above is among them. If you take anything else, check it against the full list below.

Major 123 Moderate 935 No known interaction 1,772 (incl. Niacin, Simvastatin)
Taking anything else?

Check Another of Your Medications Against Danshen

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

Everything else you take

See Every Supplement That Interacts With Niacin, Simvastatin

This page covers Danshen 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 Danshen as Part of a Dietary Supplement Product? Check It for Interactions

We hold 18 real supplement products containing Danshen, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Danshen. Your product may carry other ingredients that interact with Niacin, Simvastatin too, on top of Danshen — 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 Danshen 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 Danshen
Top half

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

29 days ago today
Medication Niacin, Simvastatin
Steady interest

#1,627 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 Danshen

What is Danshen?

Danshen
  • Heart and circulation support
  • Angina (chest pain)
  • High blood pressure
  • Anxiety and stress
  • Liver health

Danshen is a root used in traditional Chinese medicine, mainly for heart and circulation problems. Some early research is promising, but the evidence is not strong enough to confirm it works for any condition, and it may affect blood clotting. Talk to a pharmacist or doctor before using it, especially if you take other medicines or have a health condition.

Read the full Danshen monograph & all interactions
Keep checking

Other Drugs & Danshen

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

123Major
935Moderate
0Minor
1,771No known interaction
123 Major 935 Moderate 1,771 No interaction
Major

123 interactions

Showing 60 of 123 major interactions — see all 123 on the Danshen page.

Moderate

935 interactions

Showing 60 of 935 moderate interactions — see all 935 on the Danshen page.

No interaction 1,771 drugs checked — show the list

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

Showing the 60 most looked-up of 1,771 medications checked with no known interaction — see the full Danshen list.

See the full Danshen 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
Danshen 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 Danshen and Niacin, Simvastatin Together: Common Questions

Can you take Danshen with Niacin, Simvastatin?
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.
Why are there 2 interactions listed for Danshen and Niacin, Simvastatin?
Niacin, Simvastatin belongs to more than one drug category, and Danshen interacts with each of those categories a little differently. We list every one so nothing is missed — your overall risk is driven by the most serious of them.
How serious is the Danshen and Niacin, Simvastatin 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.