Upper Respiratory Tract Infection Risk

Upper respitatory tract infections (URTIs) are sicknesses that mostly affect the lung and breathing capacities, and is the cause of many cold symptoms. Supplements that reduce the risk of developing URTIs are said to promote immunity.


Research analysis by and verified by the Examine.com Research Team. Last updated on Apr 29, 2017.

Human Effect Matrix

The Human Effect Matrix looks at human studies (it excludes animal and in vitro studies) to tell you what supplements affect upper respiratory tract infection risk

Grade Level of Evidence
Robust research conducted with repeated double-blind clinical trials
Multiple studies where at least two are double-blind and placebo controlled
Single double-blind study or multiple cohort studies
Uncontrolled or observational studies only
Level of Evidence
? The amount of high quality evidence. The more evidence, the more we can trust the results.
Outcome Magnitude of effect
? The direction and size of the supplement's impact on each outcome. Some supplements can have an increasing effect, others have a decreasing effect, and others have no effect.
Consistency of research results
? Scientific research does not always agree. HIGH or VERY HIGH means that most of the scientific research agrees.
Notes
Echinacea
All comparative evidence is now gathered in our ​Supplement Goals Reference.
The evidence for each separate supplement is still freely available ​here.
Andrographis paniculata  
Colostrum  
Garlic  
Vitamin E  
Lactobacillus reuteri  
Vitamin C  
Vitamin D  
Zinc  
Lactobacillus casei  
Polypodium leucotomos