CYP2D6 is expressed in tissues including the liver, kidney, placenta, brain, breast, lungs, and small intestine. It is expressed at a low level in human liver, accounting for only approximately 3% of total CYP450 protein. In the small intestine, CYP2D6 is expressed in the duodenum and jejunum and not in the ileum and colon.
Approximately 7–10% of the Caucasian population shows an inherited deficiency in this enzyme due to the presence of one or several mutant alleles at the CYP2D6 gene locus.
CYP2D6 Inhibitors and Inducers
Potent Inhibitors | Strength | Dosage | Verified in Humans |
---|---|---|---|
9-(1,3-benzodioxol-5-yl)-1-pyrrolidin-1-ylnon-8-en-1-one1 (in black pepper) | >50 % inhibition | 10 mM[10] | ? |
Alpha-bisabolol (from German chamomile) | 50 % inhibition | IC50 = 2.18 microM[12] | ? |
Andrographis paniculata | >70% inhibition[11] | IC50 86 μg/ml | ? |
Benzyl isothiocyanate [6] | ? | ? | ? |
Berberine (in goldenseal)[1][15] | Potent inhibition (900% increase in substrates[15]) | 300 mg for 2 weeks[15] | Yes[15] |
Black Cumin seed (Nigella sativa) | 99% inhibition2 | 2.5 g twice daily for seven days | Yes[8] |
Black pepper extract | 72.8% inhibition[11] | ? | ? |
Cannabidiol (from cannabis) | ? | ? | ? |
Catharanthus roseus extract | 50% inhibition | IC50=11 microg/ml[11] | ? |
Chamazulene (from German chamomile) | 50 % inhibition | IC50 = 1.06 microM[12] | ? |
Cinnamomum burmanni | >70% inhibition[11] | IC50 1203 μg/ml | ? |
Dihydrotanshinone | 50% Inhibition | IC50=35.4 μM[9] | ? |
Goldenseal extract[1][4] | 50% Inhibition | 1070 mg3, 3 times daily | Yes |
Licorice root extract | 70% inhibition[11] | IC50= 515 μM/ml | ? |
Pipercyclobutanamide A4 (in black pepper) | >50 % inhibition | 10 mM[10] | ? |
Pomegranate extract (Punica granatum) | >70% inhibition[11] | IC50 32 μg/ml | ?5 |
Pummelo | ? | ? | ? |
Resveratrol | A 70% increase in substrates | 1 gram daily for 4 weeks | Yes[14] |
Rheum palmatum | >70% inhibition[11] | IC50 385 μg/ml | ? |
Santalum album | >70% inhibition[11] | IC50 886 μg/ml | ? |
Star fruit juice | ? | ? | ? |
Syzygium aromaticum | >70% inhibition[11] | IC50 249 μg/ml | ? |
Tinospora crispa | >70% inhibition[11] | IC50 488 μg/ml | ? |
Zingiber aromaticum | >70% inhibition[11] | IC50 693 μg/ml | ? |
Moderate Inhibitors | Strength | Dosage | Verified in in Humans |
Alpha-asarone (found in Calamus EO) [2] | ? | IC50 = 55.2 μg/ml | ? |
Calamus EO [2] | ? | 1-3 drops (unverified) | ? |
Pi. cubeba | ? | ? | ? |
Quercetin | ? | ? | ? |
Zingiber aromaticum | ? | ? | ? |
Weak Inhibitors | Strength | Dosage | Verified in in Humans |
Black cohosh [4] | Weak inhibition | ? | Yes |
Black cohosh extract6 [1] | No effect | 40 mg, twice daily | Yes |
Capsaicin (found in cayenne pepper, habanero peppers, etc.) | ? | ? | ? |
Cayenne pepper | ? | ? | ? |
Cryptotanshinone | ? | ? | ? |
Curcuma heyneana | ? | ? | ? |
Curcumin | ? | ? | ? |
German chamomile EO | ? | ? | ? |
Habanero pepper | ? | ? | ? |
Hydrastine (in goldenseal)[1] | 50% Inhibition | (IC50 = 350 μM | ? |
Safrole | ? | ? | ? |
Sage [5] | ? | ? | ? |
Tanshinone I | ? | ? | ? |
Turmeric | ? | ? | ? |
In Vitro Inhibitors Inactive in Humans | Strength | Dosage | Verified in in Humans |
Echinacea purpurea extract7 [1] | Inactive | 267 mg, three times daily | Yes |
Milk Thistle extract8 [1] | Inactive | 300 mg, three times daily | Yes |
Ginkgo biloba [4] | Inactive | ? | Yes |
Kava [4] | Inactive | ? | Yes |
Saint John’s Wort extract9 [1] | Inactive | 300 mg, three times daily | Yes |
Valerian Root [4] | Inactive | ? | Yes |
White grapefruit juice [7] | Inactive | 3 cups | Yes |
In Vitro Inhibitors Inactive in Rats | Strength | Dosage | Verified in Humans |
Chamomile [13] | Inactive | ? | ? |
Inducers | Strength | Dosage | Verified in Humans |
Valerian root (inhibits then induces) | ? | ? | ? |
Valerian root EO | ? | 2-5 drops (unverified) | ? |
If an inducer or inhibitor is present on this page and reliable human in vivo studies are available but not shown on this page please leave a comment about it using the Discuss link at the bottom of this page so we can update the inhibitor's data.