St. John's Wort: The Full Interaction List You Need to Read

If you read one ingredient page before taking any supplement containing St. John's Wort, make it this one. The interaction profile is not a formality.

The mechanism behind the interactions

Hyperforin, one of the characterised constituents of Hypericum perforatum, is a potent inducer of the cytochrome P450 enzyme CYP3A4 and of the P-glycoprotein transporter. In plain terms, it makes the liver and gut clear a large number of medicines faster than normal, lowering their blood concentrations. Because CYP3A4 metabolises a very large share of prescription drugs, the list of affected medicines is unusually long. Separately, St. John's Wort has serotonergic activity, which creates a different category of risk.

Which medicines are affected

Documented or strongly suspected interactions include hormonal contraceptives, where breakthrough bleeding and contraceptive failure are reported; warfarin and other anticoagulants; ciclosporin and tacrolimus, where transplant rejection has been reported; digoxin; some statins; antiretrovirals used in HIV treatment; certain cancer medicines including some tyrosine kinase inhibitors; some anticonvulsants; theophylline; and certain benzodiazepines. With SSRIs, SNRIs, MAOIs, triptans, tramadol and other serotonergic agents there is a serotonin syndrome risk rather than a reduced-efficacy risk.

What to do about it

Do not take a St. John's Wort-containing product alongside any prescription medicine without a pharmacist or doctor check first. This is free, takes minutes, and pharmacists have interaction databases they can query immediately. Note that the risk does not end when you stop - enzyme induction takes time to reverse, so drug levels can shift again on discontinuation. Also note that hormonal contraception is the interaction most people are unaware of, and it is one of the most consequential.

How this relates to Cognizil

Cognizil works through nutrient and botanical support rather than any acute stimulant effect, so it is not designed to produce a same-day change — the Bacopa research it rests on ran to roughly twelve weeks. Our 30-day assessment guide explains how to test it properly against a recorded baseline. The Cognizil discount is applied automatically by quantity on the order page.