Echinacea purpurea is an herb commonly used either in response to or daily for prevention of the common cold. It outperforms placebo unreliably and the amount of benefit derived is similarly unreliable.
Echinacea is most often used for
The term "echinacea" refers to a genera of plants, and a few species in this family including purpurea and angustifolia are desired due to their alkylamide content (seen as the active ingredients). It's often taken as a tincture, but dry capsules are also common.
Overall, echinacea appears to be somewhat effective for fighting off upper respiratory tract infections (mostly studied for the common cold), and when taken consistently as a prophylactic, it has support from research. It has also been studied for its potential ability to accelerate the rate of recovery in sickness, but the current evidence for that highly ambiguous. There are trials suggesting remarkable recovery rates, and there are trials suggesting no benefits whatsoever. Overall, it doesn't look very potent. Limited research suggests that it can increase the levels of a variety of immune cells, but more research is needed to be confident in this.
Echinacea hasn't demonstrated notably, greater adverse events in trials than placebo, however, as with herbal extracts in general, there may be a risk for drug interactions, particularly for those who take multiple medications.
- Brauneria purpurea
- Echinacea intermedia
- Rudbeckia purpurea
- Purple coneflower herb
- Red sunflower
For dehydrated powders (including encapsulated echinacea) the species of purpuera tends to be used and oral doses are taken upwards of 300mg thrice a day (900mg daily) and 500mg thrice daily (1,500mg daily).
Tinctures of an ethanolic extract of the aerial parts (leaves and stems) appears to be used in the concentration of 2.5mL thrice a day or up to 10mL daily.
There is no much evidence as to whether these are the optimal doses, and studies seem to be very hetereogeneous in their benefits due to lack of standardization.