Supplement analysis backed by scientific evidence · PT · ES · DE · FR

← All supplements
Limited evidenceImmunity

Echinacea

The most-studied cold remedy in the supplement aisle, and still an unresolved one: the Cochrane review of 24 trials found no reliable treatment effect and only a small, statistically fragile prevention signal. Product-to-product variability in species and plant part makes the literature nearly impossible to pool.

View on iHerb Ships to 180+ countries · welcome discount for new customers

What the science says

  • Treating an established cold Limited evidence

    The 2014 Cochrane review (24 trials, ~4,600 participants) concluded that Echinacea products do not reliably shorten or lessen a cold once symptoms have started; individual positive trials exist but are outweighed by null results and heterogeneity. Where an effect was seen, it amounted to roughly half a day to a day and a half of illness — within the noise of unblinded symptom diaries.

  • Preventing colds and respiratory infections Limited evidence

    Cochrane found a weak prevention trend (relative risk ~0.83-0.90) that lost significance in most sensitivity analyses. An industry-linked meta-analysis of 6 trials (Schapowal 2015) reported a 35% reduction in recurrent infections and fewer complications, but it pooled a narrow set of trials on one alcoholic E. purpurea extract and is not independent confirmation.

  • Preparations are not interchangeable Limited evidence

    Trials have used E. purpurea, E. angustifolia and E. pallida, and root versus aerial parts, in pressed juice, alcoholic tincture and dried powder. Marker compounds (alkylamides, cichoric acid) vary several-fold between commercial products, so a positive trial on one extract says little about the bottle on the shelf.

Dosage & safety

Studied doseTrial doses vary by preparation. Pressed juice of E. purpurea aerial parts: 6-9 mL/day. Standardized alcoholic extract (e.g. 2,400 mg/day of a 1:11 tincture) during the cold season, raised to 4,000 mg/day at symptom onset. Dried root: 900-1,500 mg/day in divided doses. Typical courses run 7-10 days for treatment and up to 4 months for prevention.
SafetyGenerally well tolerated; the commonest complaints are rash, GI upset and unpleasant taste. Echinacea is in the Asteraceae family, so people allergic to ragweed, chrysanthemums, marigolds or daisies can react, and anaphylaxis has been reported (Australia's TGA issued a warning after ~50 hypersensitivity reports). Rare hepatitis and autoimmune-flare case reports exist. Avoid in progressive systemic disease (tuberculosis, HIV, multiple sclerosis) and with immunosuppressants such as tacrolimus or ciclosporin, since immune-modulating effects are theoretically opposed. It weakly inhibits CYP1A2 and may affect caffeine clearance. Data in pregnancy are limited but not alarming.

How to take it

TimingSplit it into divided doses and start at the first symptom rather than after a day or two.
With food?Food makes no meaningful difference.
Worth knowingTreatment courses run 7-10 days; the preventive use is the weaker evidence and means months of continuous dosing.

Interactions

With medications

  • tacrolimus, ciclosporin and other immunosuppressants

    Echinacea's immune-modulating action theoretically opposes the drug's purpose. do not combine after transplant or on immunosuppressive therapy

  • caffeine and other CYP1A2 substrates

    Echinacea weakly inhibits CYP1A2 and can slow their clearance. no action needed unless you are on a narrow-therapeutic-index CYP1A2 drug such as theophylline

Well-established interactions only — this is not a complete list. Always tell your doctor and pharmacist what you take.

Frequently asked questions

Does echinacea shorten a cold?

The evidence is limited: the 2014 Cochrane review of 24 trials concluded echinacea does not reliably shorten or lessen a cold once symptoms start. Where an effect was seen it amounted to roughly half a day to a day and a half.

Can echinacea prevent colds?

Cochrane found only a weak prevention trend for echinacea that lost significance in most sensitivity analyses. An industry-linked meta-analysis reporting a 35% reduction pooled trials of a single extract and is not independent confirmation.

Which echinacea product and dose should I use?

Echinacea products are not interchangeable: species, plant part and preparation differ, and marker compounds vary several-fold. Trial doses include 6-9 mL/day of E. purpurea pressed juice or 900-1,500 mg/day of dried root, usually for 7-10 days starting at the first symptom.

Who should not take echinacea?

People allergic to ragweed, chrysanthemums, marigolds or daisies can react to echinacea, including rare anaphylaxis. Avoid echinacea with immunosuppressants such as tacrolimus or ciclosporin and in progressive systemic diseases such as tuberculosis, HIV or multiple sclerosis.

Scientific references

Where to buy

Nature's Way, Echinacea Purpurea Herb, 180 Vegan Capsules (400 mg per Capsule)

View on iHerb

Ships to 180+ countries · welcome discount for new customers

Referral link — this site may earn a commission on purchases.

Related in Immunity