Turmeric / curcumin — interactions

Curcuminoids inhibit several CYPs plus the phase-2 conjugating enzymes (UGT and SULT). Phase 2 matters here: the corpus' own metabolism files turn on glucuronidation and sulfation, and this is a common seasoning that moves both.

Also known as: curcumin, Curcuma longa, curcuminoids. Category: seasoning.

What it does, mechanism by mechanism

CYP3A4 inhibition — inhibits, moderate

Slows the enzyme that metabolises roughly half of all prescription drugs. A CYP3A4 substrate taken with a CYP3A4 inhibitor reaches higher blood levels than its dose implies.

Also inhibits UGT and SULT — a phase-2 interaction, which most interaction checkers do not model at all.

Sources: Volak LP 2008, Bahramsoltani R 2017 · more on CYP3A4 inhibition

CYP2C9 inhibition — inhibits, moderate

Slows the enzyme handling S-warfarin, phenytoin and NSAIDs. S-warfarin is the clinically dominant enantiomer; small shifts move the INR.

Sources: Volak LP 2008, Bahramsoltani R 2017 · more on CYP2C9 inhibition

UGT inhibition (glucuronidation) — inhibits, moderate

Slows the phase-2 conjugation that makes a compound water-soluble enough to excrete. Phase 2 is the step most interaction checkers skip. Cannabinoids are heavily glucuronidated, so this is not a side issue in this corpus.

Curcuminoids inhibit UDP-glucuronosyltransferase as well as the CYPs, which is a phase-2 interaction and is exactly the pathway cannabinoids are cleared through.

Sources: Volak LP 2008 · more on UGT inhibition (glucuronidation)

SULT inhibition (sulfation) — inhibits, moderate

Slows sulfotransferase conjugation, which is also readily saturated by a large phenolic load. Saturation and inhibition look the same from outside: the substrate is routed down a different pathway than expected.

Sources: Volak LP 2008 · more on SULT inhibition (sulfation)

What it reaches in this dataset

Via CYP3A4 inhibition

Via CYP2C9 inhibition

Via UGT inhibition (glucuronidation)

This list is what is IN the table. It is not the set of substances this interacts with — that set is larger and partly unknown, and the mechanism is the thing to carry to a substance we have not listed.

Specific combinations

What a clean result means here

A clean result means NO DOCUMENTED INTERACTION IN THIS DATASET. It does not mean safe, and it is not a clearance. Most substances are not in this dataset at all, and for many pairs that are, nobody has ever studied the combination.

In this dataset

  • Monoamine oxidase inhibition (prescription MAOIs, RIMAs, linezolid, methylene blue, harmala alkaloids)
  • Serotonergic drugs and the serotonin-toxicity mechanism
  • Dietary tyramine and L-dopa loads
  • The major cytochrome P450 pathways: CYP3A4, CYP2D6, CYP1A2, CYP2C9, CYP2C19 — inhibition and induction
  • P-glycoprotein inhibition and induction
  • 11β-HSD2 inhibition (the licorice mechanism) and the potassium consequences that follow it
  • QT prolongation as an additive pharmacodynamic axis
  • Culinary seasonings and common foods with documented pharmacological activity
  • A selected set of narrow-therapeutic-index drugs where those shifts matter most
  • The endocannabinoid enzymes and transport: FAAH, MAGL, endocannabinoid membrane transport, CB1 and CB2
  • Additive CNS depression and GABA-A positive modulation — the alcohol / benzodiazepine / opioid / kava axis
  • The phytocannabinoids delta-9-THC, cannabidiol and the converted cannabinoids, as both substrates and inhibitors
  • Synthetic full CB1 agonists as a class, and why they are pharmacologically unlike cannabis
  • CYP2E1, and phase-2 glucuronidation and sulfation where a specific entry names them
  • The sedative and potentiator botanicals of the kava literature, and dietary L-dopa from Mucuna

Not in this dataset

  • Any substance not named in this dataset — which is most substances. There are tens of thousands of marketed drugs and this table holds fewer than a hundred entries.
  • Phase-2 conjugation (UGT, SULT, NAT2, COMT) except where a specific entry names it. The oilahuasca corpus turns heavily on phase 2 and this engine models it only in passing.
  • Pharmacogenomics. CYP2D6 and CYP2C19 are strongly polymorphic; a poor metaboliser and an ultra-rapid metaboliser can have opposite outcomes from the same pair, and this engine does not know your genotype.
  • Dose, timing, duration, formulation and route — all of which change whether a documented interaction is clinically real for you.
  • Renal and hepatic impairment, age, pregnancy, and body composition.
  • Bleeding and antiplatelet risk, hypoglycaemia, anticholinergic load, and most other pharmacodynamic axes beyond the ones listed above. Additive CNS depression and GABA-A modulation ARE now modelled — see the covers list — but the absence of a sedation finding still only means the agents you named are not on that axis in this dataset.
  • Herb–herb interactions outside the named entries, and essentially the whole botanical world: most plants have no interaction literature at all.
  • Allergy, intolerance, and contamination or adulteration of unregulated products.
  • Anything published after the last-reviewed date below.
  • Bleeding and antiplatelet risk, which is the mechanism that matters most for garlic, ginkgo and several other common supplements. It is not modelled at all, so a clean result says nothing about it.
  • Whether any of the natural FAAH, MAGL or transport inhibition reported in vitro occurs at all at a dose a person would take. For most of these compounds nobody has measured it.
  • The actual contents of an unregulated cannabinoid product. This engine models named compounds; an unidentified isomer or side-product in a converted-cannabinoid product is outside it by construction.
  • Dose. Every cannabinoid interaction here scales with dose, and consumer product labelling for this category is repeatedly found inaccurate in published surveys.
  • Inhalation-specific hazards — thermal degradation products, diluents chosen for rheology rather than for inhalation toxicology, and carrier and adulterant contamination.

101 substances, 33 mechanisms, 101 citations. Last reviewed . Primary literature (every DOI resolved against the Crossref API) and FDA drug labelling. There is no free, openly-licensed, comprehensive drug-interaction dataset to draw on; NLM retired its Drug Interaction API on 2024-01-02 and DrugBank's interaction set is a commercial licence.

References

  1. Volak LP, Ghirmai S, Cashman JR, Court MH (2008). Curcuminoids Inhibit Multiple Human Cytochromes P450, UDP-Glucuronosyltransferase, and Sulfotransferase Enzymes, whereas Piperine is a Relatively Selective CYP3A4 Inhibitor. Drug Metabolism and Disposition. doi:10.1124/dmd.108.020552
  2. Bahramsoltani R, Rahimi R, Farzaei MH (2017). Pharmacokinetic interactions of curcuminoids with conventional drugs: A review. Journal of Ethnopharmacology. doi:10.1016/j.jep.2017.07.022

Every DOI above was resolved against the Crossref API on 2026-09-09 and the returned title checked against the one printed here. Three DOIs in the first draft resolved to real but different papers and were corrected before publication.

Last reviewed . All interaction pages.