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About Grapefruit Seed Extract
Plant: Citrus paradisi (grapefruit seed extract)
Used in the source protocol as an alternative to rifampin/tinidazole for cyst-form Borrelia.
Reference dosing
| Dosing | No dose is given in the main source material. Napiers lists Viridian Grapefruit Seed Extract capsules (400 mg per capsule): 1 to 3 capsules daily with food. Follow the label or your practitioner. |
Can change how the body handles many prescription medicines (it affects liver enzymes, as grapefruit does), so blood levels can become unpredictable. ConsumerLab lists statins, benzodiazepines, carbamazepine, cyclosporine, protease inhibitors and estrogen. Some liquid products have been found adulterated with synthetic preservatives such as benzethonium chloride or triclosan, and benzethonium chloride has been linked to reduced warfarin effect in case reports. Not recommended in pregnancy or breastfeeding (Napiers/Viridian label). Check with your prescriber or pharmacist before combining it with anything.
These are figures from the sources used on this site. They are not a prescription. Follow the product label and your prescriber.
Safety and cautions
Contraindications: A strong CYP3A4 inhibitor — significantly raises blood levels of many other medications (certain statins, some calcium channel blockers, immunosuppressants). Review all current prescriptions with a doctor or pharmacist before combining. Also: some liquid products have been found adulterated with synthetic preservatives (benzethonium chloride, triclosan), and benzethonium chloride has been linked to reduced warfarin effect in case reports. ConsumerLab also lists statins, benzodiazepines, carbamazepine, protease inhibitors and estrogen as grapefruit-type interactions. Not recommended in pregnancy or breastfeeding.
Herbs can interact with prescription medicines and other supplements. Check with your prescriber or pharmacist first, and do not use herbs in pregnancy or while breastfeeding unless a doctor agrees.
Information last checked: 6 November 2026.
Symptoms linked to this herb
Traditional uses from our symptom map. Not medical advice.
Where to buy
Napiers (UK)Higher Nature Citricidal Grapefruit Seed Extract — 25 ml · See product page · LiquidNapiers (UK)Viridian Grapefruit Seed Extract Capsules · £12.00 (30 capsules) · Capsules, 400 mgCheck the label and the seller. A link is not a recommendation.
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Educational only, not medical advice. See the disclaimer.