Supplement analysis backed by scientific evidence · PT

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Limited evidenceImmunity

Hyssop

A Mediterranean mint-family herb with a long tradition in cough and cold remedies. There is essentially no clinical research behind that use; the only controlled trial is a small one in asthma.

Evidence last reviewed: August 2026

What the science says

  • No trials for coughs or colds Limited evidence

    Despite centuries of traditional use for respiratory complaints, no controlled trial of hyssop for cough, colds or influenza is indexed in PubMed. A 2022 review of Hyssopus essential oil found only laboratory work on antimicrobial and antioxidant activity, with no human efficacy data.

  • One small asthma trial Limited evidence

    A randomized, double-blind, placebo-controlled trial of hyssop syrup in mild to moderate asthma reported improvement in symptom scores. It is a single small trial in a different condition from the one hyssop is usually sold for, and it has not been replicated.

Dosage & safety

Studied doseNo dose has been established. Traditional use is 1–2 g of dried herb as an infusion, two to three times a day; commercial syrups follow their own label.
SafetyThe essential oil contains pinocamphone, which is convulsant at high doses — the oil should not be taken internally, and people with epilepsy should avoid hyssop preparations entirely. Avoid in pregnancy. Not enough data to judge long-term use.

Scientific references

Where to buy

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