Bergamottin

Bergamottin (and its metabolite 6',7'-dihydroxybergamottin) irreversibly inhibits intestinal cytochrome P450 3A4 (CYP3A4), the enzyme that metabolizes many medications. By disabling CYP3A4 in the gut wall, bergamottin increases the bioavailability and blood levels of affected drugs, sometimes dangerously. This is the mechanism behind why grapefruit juice can raise levels of statins, calcium channel blockers, immunosuppressants, and many other medications. In supplements, bergamottin is rarely intentionally included; it appears as a label disclosure when grapefruit or bergamot extracts are used.

There is no recommended supplemental dose. Even small amounts of bergamottin (from one glass of grapefruit juice) can meaningfully inhibit CYP3A4 for 24-72 hours.

Not applicable as a supplement. If consuming grapefruit-derived products, separating from medication does not reliably avoid the interaction because CYP3A4 inhibition lasts 24-72 hours.

Bergamottin itself is not directly toxic at dietary levels, but it can dramatically alter drug exposure. Furanocoumarins can also cause skin photosensitivity if applied topically and exposed to sunlight (phytophotodermatitis).

Major: bergamottin inhibits CYP3A4 and can elevate blood levels of statins (simvastatin, atorvastatin, lovastatin), calcium channel blockers (felodipine, nifedipine), immunosuppressants (cyclosporine, tacrolimus), some antiarrhythmics, certain benzodiazepines, sildenafil, and many other drugs. Check with a pharmacist if you take prescription medication and consume grapefruit or bergamot products regularly.