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OtherNo evidence

Grapefruit seed extract

Also known as: GSE

Grapefruit seed extract (GSE) is made from grapefruit seeds, pulp and peel and sold as a 'natural antibiotic'. Independent analyses, however, found that the antimicrobial effect of some commercial products came from added synthetic preservatives (e.g. benzethonium chloride); clinical evidence in humans is lacking.

What it is used for

  • antimicrobial and antifungal effect – no reliable human evidence, lab data are questioned because of contaminants
  • support during colds and digestive complaints – no evidence, traditional use

Forms and how they differ

drops (concentrate)

always dilute in water or juice before use

capsules

composition and purity vary widely between products

When to take it

Diluted in water, with food, short term.

Pairs well with

Enough fluids and a varied diet; rest during a cold.

Do not combine / separate

Be careful with medicines – grapefruit affects how the liver and gut break down many medicines; if you take any medicines, consult your doctor.

Watch out for

Do not use during pregnancy, breastfeeding or in children. If you are allergic to citrus, have liver or kidney disease, or take medicines, consult your doctor.

Safety

Never take the undiluted concentrate – it can damage mucous membranes. Do not exceed the label dose.

Practical tip

For a bacterial infection, GSE is no substitute for treatment prescribed by a doctor.

Products containing Grapefruit seed extract 1

Grapefruit seed extractliquidImmunityDigestion & gut
How to read the evidence rating
Strong evidenceModerate evidenceWeak evidenceNo evidence

Strong = several good human studies or official recommendations; moderate = promising but smaller studies; weak = few studies or mixed results; no evidence = claims not confirmed.

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Select the supplements you take and, if relevant, your medicines. We show what interferes, what needs a time gap and what to watch out for.

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From the same group

AlfalfaNo evidenceAndrographisWeak evidenceAroniaWeak evidenceBarley grassWeak evidenceBee pollenWeak evidenceBeef organs (desiccated)Weak evidence
Important notice

This information is educational and does not replace advice from a doctor or pharmacist. We do not give medicine dosages. Supplements are no substitute for a varied diet; if pregnant, breastfeeding, ill or on medication, consult a doctor first.