Upper respiratory tract infection (URTI)
Supplements studied for upper respiratory tract infection (URTI).
Overview
Several supplements show medium-level evidence for reducing upper respiratory tract infections. Vitamin D (14 studies) may lower croup risk in children when mothers took 2800 IU daily during late pregnancy. American Ginseng extract (Cold-FX) may reduce cold frequency and duration during influenza season when taken twice daily for months. Beta-Glucan from yeast may lower infection likelihood by about 65% and reduce symptom severity and duration.
Echinacea (10 studies) carries low ratings, though detailed summaries are not available here. Eleuthero has only been tested in combination products such as Kan Jang, with mixed results for cough relief. See the heatmap and evidence reviews below for evidence across nine supplements.
Effect graph
Relevant supplements
Relevant supplements sorted by DEX Score.
| Vitamin D | ★★★★★ | Medium |
| American Ginseng | ★★★★★ | Medium |
| Beta-Glucan | ★★★★★ | Medium |
| Echinacea | ★★★★★ | Low |
| Eleuthero | ★★★★★ | Low |
| Resveratrol | ★★★★★ | Low |
| Quercetin | ★★★★★ | Low |
| Vitamin A | ★★★★★ | Very Low / None |
| Green Tea | ★★★★★ | Very Low / None |
Studies
Find individual evidence reviews for supplements sorted by DEX Score.
9 supplements for , and rated at least stars. All purchase bands. No minimum star filter.
American GinsengView supplement →
Consider purchase·★★★★★
How we scored this▸
- Taking a specific American ginseng extract called CVT-E002 (Cold-FX) during flu season may help reduce the number of colds and shorten how long they last in adults.
- This extract works best when taken twice daily for several months, especially in older adults who have also had the flu vaccine.
- It seems to lower the chance of getting repeat colds but might not stop the first cold of the season.
- This extract is generally safe and well tolerated.
- In children, early studies show it is safe but do not prove it helps with cold symptoms.
- Supplementation does not appear to protect people with weakened immune systems from respiratory infections.
Browse 6 studies
RCTA randomized, controlled trial of Panax quinquefolius extract (CVT-E002) to reduce respiratory infection in patients with chronic lymphocytic leukemia2012n=293
In 293 early-stage CLL patients, CVT-E002 American ginseng did not reduce acute respiratory illness days versus placebo, though moderate sore throat and grade ≥3 toxicities were less frequent with ginseng.
- Effect
- No Benefit
- Population
- Patients with CLL
- Participants
- 293
RCTEfficacy and Safety of CVT-E002, a Proprietary Extract of Panax quinquefolius in the Prevention of Respiratory Infections in Influenza-Vaccinated Community-Dwelling Adults: A Multicenter, Randomized, Double-Blind, and Placebo-Controlled Trial2011
In 783 influenza-vaccinated adults over 6 months, CVT-E002 400–800 mg/day did not reduce laboratory-confirmed URI incidence but lowered Jackson-confirmed URI severity and duration.
- Effect
- No Benefit
- Duration
- 6 months
- Dose
- 400–800 mg/day
- Population
- Healthy adults
- Ages
- 65+
RCTSafety and tolerability of North American ginseng extract in the treatment of pediatric upper respiratory tract infection: a phase II randomized, controlled trial of 2 dosing schedules2008n=75
This PubMed record's abstract describes a rat cerebral ischemia microcirculation study, not the listed pediatric American ginseng URTI trial; no reliable ginseng outcome data are available from the abstract.
- Effect
- No Benefit
- Population
- Children/adolescents
- Participants
- 75
RCTEfficacy of COLD-fX in the prevention of respiratory symptoms in community-dwelling adults: a randomized, double-blinded, placebo controlled trial2006
In 43 community-dwelling seniors over 4 months, COLD-fX 400 mg/day after flu vaccine reduced acute respiratory illness incidence 48% and symptom duration 55% versus placebo in the last 2 months.
- Effect
- Benefit
- Duration
- 4 months
- Dose
- 400 mg/day
- Population
- Healthy adults
- Avg age
- ~65
RCTEfficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial2005n=323
In 323 healthy adults aged 18–65 over 4 months, North American ginseng extract reduced colds per person 0.68 vs 0.93, severe symptom scores, and total cold days 10.8 vs 16.5 versus placebo.
- Effect
- Benefit
- Duration
- 4 months
- Population
- Healthy adults
- Participants
- 323
- Ages
- 18–65
RCTA placebo-controlled trial of a proprietary extract of North American ginseng (CVT-E002) to prevent acute respiratory illness in institutionalized older adults2004n=101
In two trials totaling 198 institutionalized older adults, CVT-E002 400 mg/day reduced laboratory-confirmed influenza/RSV illness odds ~7–10-fold versus placebo during flu season.
- Effect
- Benefit
- Duration
- 8–12 weeks
- Dose
- 400 mg/day
- Population
- Women
- Participants
- 101
- Avg age
- ~81
Vitamin DView supplement →
Consider purchase·★★★★★
How we scored this▸
- A large study found that pregnant women who took 2800 IU of vitamin D daily from about six months of pregnancy until one week after birth had children who were 40% less likely to develop croup by age three compared to those who took a placebo.
- This benefit was seen even when considering other factors like omega-3 supplements and children’s breathing problems.
Browse 14 studies·1 meta-analysis
MetaEffect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis2024
A meta-analysis of 18 studies in 36,707 dark-skinned individuals found no significant effect of vitamin D supplementation on acute respiratory tract infections (OR 1.40).
- Effect
- No Benefit
- Population
- Adults
RCTEffect of Monthly High-Dose Vitamin D Supplementation on Acute Respiratory Infections in Older Adults: A Randomized Controlled Trial2020n=2,558
An RCT in 5,110 adults aged 50–84 found monthly vitamin D3 (200,000 IU then 100,000 IU/month) did not reduce acute respiratory infection incidence versus placebo.
- Effect
- No Benefit
- Dose
- 200,000 IU then 100,000 IU/month vitamin D3
- Population
- Older adults
- Participants
- 2,558
- Ages
- 50–84
RCTEffect of Vitamin D supplementation to reduce respiratory infections in children and adolescents in Vietnam: A randomized controlled trial2019n=1,300
In 1,300 Vietnamese children given 14,000 IU/week for 8 months, vitamin D did not reduce influenza but modestly reduced non-influenza respiratory viral infections (HR 0.76).
- Effect
- Benefit
- Duration
- 8 months
- Dose
- 2000 IU/day
- Population
- Children/adolescents
- Participants
- 1,300
- Ages
- 3–17
RCTIntake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study2018n=28
In 215 Japanese adults with low 25(OH)D given 10 µg/day 25-hydroxyvitamin D3 for 16 weeks, supplementation shortened URTI duration and improved symptom severity versus placebo.
- Effect
- Benefit
- Dose
- 10 mcg/day
- Population
- Adults
- Participants
- 28
- Ages
- 45–74
RCTVitamin D₃ Supplementation Reduces the Symptoms of Upper Respiratory Tract Infection during Winter Training in Vitamin D-Insufficient Taekwondo Athletes: A Randomized Controlled Trial2018n=13
A 4-week RCT in 13 vitamin D-insufficient taekwondo athletes found vitamin D3 5,000 IU/day reduced URTI symptoms during winter training versus placebo.
- Effect
- Benefit
- Duration
- 4 weeks
- Dose
- 5000 IU/day
- Population
- Athletes
- Participants
- 13
- Ages
- 19–22
RCTEffect of High-Dose vs Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy Children2017n=49
In 703 Canadian children aged 1–5 given 2000 versus 400 IU/day for ≥4 months, high-dose vitamin D did not reduce laboratory-confirmed upper respiratory infections.
- Effect
- No Benefit
- Dose
- 400 IU/day
- Population
- Children/adolescents
- Participants
- 49
- Ages
- 1–5
RCTVitamin D supplementation and upper respiratory tract infections in adolescent swimmers: a randomized controlled trial2015
An RCT in adolescent swimmers with vitamin D insufficiency found 2,000 IU/day vitamin D3 reduced URI burden during training versus placebo.
- Effect
- Benefit
- Dose
- 2000 IU/day
- Population
- Children/adolescents
RCTVitamin D3 and gargling for the prevention of upper respiratory tract infections: a randomized controlled trial2014n=85
In 600 university students given 10,000 IU/week vitamin D for ~2 months, vitamin D nonsignificantly reduced clinical URTIs but significantly lowered laboratory-confirmed infection risk (RR 0.54).
- Effect
- Benefit
- Dose
- 10000 IU/week
- Population
- Pregnant women
- Participants
- 85
RCTVitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trial2013n=2,228
In 759 adults given 1000 IU/day vitamin D in a colorectal adenoma trial, supplementation did not reduce winter upper respiratory tract infection episodes or duration over 4–5 years.
- Effect
- No Benefit
- Dose
- 1000 IU/day
- Population
- Healthy adults
- Participants
- 2,228
- Ages
- 45–75
RCTEffect of vitamin D3 supplementation on upper respiratory tract infections in healthy adults: the VIDARIS randomized controlled trial2012n=161
An RCT in 161 healthy adults found a single high dose of vitamin D3 did not significantly reduce URTI incidence or severity versus placebo.
- Effect
- No Benefit
- Duration
- 18 months
- Dose
- 200000 IU/day
- Population
- Healthy adults
- Participants
- 161
RCTVitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention study2012n=140
A 1-year RCT in 140 adults with frequent respiratory tract infections found vitamin D3 4,000 IU/day reduced infection frequency versus placebo.
- Effect
- Benefit
- Duration
- 1 year
- Dose
- 4000 IU/day
- Population
- Patients
- Participants
- 140
- Ages
- 18–75
RCTVitamin D supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young Finnish men2010
A randomized double-blind trial among young Finnish men evaluated vitamin D supplementation for prevention of acute respiratory tract infections.
- Population
- Men
RCTA randomized controlled trial of vitamin D3 supplementation for the prevention of symptomatic upper respiratory tract infections2009n=162
A 12-week RCT in 162 adults found vitamin D3 2,000 IU/day did not significantly reduce upper respiratory tract infection incidence or severity versus placebo.
- Effect
- No Benefit
- Duration
- 12 weeks
- Dose
- 2000 IU/day
- Population
- Healthy adults
- Participants
- 162
RCTVitamin D supplementation to prevent infections: a sub-study of a randomised placebo-controlled trial in older people (RECORD trial, ISRCTN 51647438)2007
A sub-study of the RECORD trial in older adults evaluated whether vitamin D supplementation prevents infections in a randomized placebo-controlled design.
- Population
- Older adults
Beta-GlucanView supplement →
Consider purchase·★★★★★
How we scored this▸
- Taking supplements that contain yeast-derived beta-glucans can help reduce the chance of getting colds and other upper respiratory infections.
- Studies show that taking beta-glucan daily for a few weeks to several months lowers the likelihood of catching these infections by about 65%, shortens how long symptoms last, and makes symptoms less severe.
- Beta-glucans help boost the immune system by activating immune cells and improving gut health.
- In young children (ages 2 to 6) who often get respiratory infections, a product that combined beta-glucans with elderberry, zinc, and vitamin D did not lower the number of infections while being taken.
- However, there were fewer infections months after stopping the supplement.
- More research is needed to know how well beta-glucans work in children.
Browse 2 studies·1 meta-analysis
RCTEffects of Chronic Barley Consumption on Upper Respiratory Tract Symptoms in Japanese Healthy Adults: A Randomized, Parallel-Group, Controlled Trial2024n=54
A randomized, parallel-group controlled trial in healthy Japanese adults found that daily consumption of cooked waxy barley (containing ~1.8 g β-(1,3/1,4)-glucan) for 8 weeks reduced cumulative days of sneezing and fatigue, and lessened severity of nasal symptoms and tension compared with white rice.
- Effect
- Benefit
- Duration
- 8 weeks
- Dose
- 100 g/day
- Population
- Healthy adults
- Participants
- 54
MetaEffects of yeast β-glucans for the prevention and treatment of upper respiratory tract infection in healthy subjects: a systematic review and meta-analysis2021
A meta-analysis of 13 RCTs found yeast beta-glucan significantly reduced URTI incidence (OR 0.35), episode count (SMD −0.32), and duration (SMD −0.31) versus placebo in healthy subjects.
- Effect
- Benefit
- Population
- Healthy adults
EchinaceaView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- No summary is available.
Browse 10 studies·1 meta-analysis
MetaEfficacy and safety of Echinacea purpurea in treating upper respiratory infections and complications of otitis media in children: Systematic review and meta-analysis2025n=1,651
A meta-analysis of 9 pediatric RCTs (1,651 placebo, 1,518 treatment) found E. purpurea reduced URTI duration (SMD −0.19), incidence (RR 0.81), and antibiotic use (RR 0.18), and lowered otitis media episodes (RR 0.56), with mildly increased adverse events.
- Effect
- Benefit
- Population
- Children/adolescents
- Participants
- 1,651
RCTTherapeutic Potential of a Natural Blend of Aronia melancarpa, Lonicera caerulea, and Echinacea purpurea Extracts in Treating Upper Respiratory Tract Infections: Preliminary Clinical and In Vitro Immunomodulatory Insights2024n=61
In 61 URTI-prone adults over 60 days, an ELA blend (echinacea, Lonicera, Aronia) reduced URTI episodes (2 vs 8; p = 0.044) and throat symptoms (8 vs 16; p = 0.038) versus placebo, with in vitro antiviral and immunomodulatory effects.
- Effect
- Benefit
- Duration
- 60 days
- Population
- RA patients
- Participants
- 61
- Ages
- 18–70
RCTEvaluating the Efficacy and Safety of EZC Pak, a 5-Day Combination Echinacea-Zinc-Vitamin C Dose Pack with or without Vitamin D, in the Management of Outpatient Upper Respiratory Infections2023n=360
In 360 outpatients with URIs, EZC Pak (echinacea-zinc-vitamin C) shortened illness by 1.39 days (p = 0.017) and reduced symptom severity by 17.4% (p = 0.029) versus placebo; adding vitamin D did not add benefit.
- Effect
- Benefit
- Duration
- 5 days
- Population
- RA patients
- Participants
- 360
- Ages
- 18+
RCTEchinacea Purpurea For the Long-Term Prevention of Viral Respiratory Tract Infections During Covid-19 Pandemic: A Randomized, Open, Controlled, Exploratory Clinical Study2022n=120
In 120 healthy adults over ~6 months, daily 2,400 mg E. purpurea reduced any viral RTI (RR 0.68) and SARS-CoV-2 positivity (RR 0.37, p = 0.03) versus control, with fewer fever days during acute treatment.
- Effect
- Benefit
- Dose
- 2400 mg/day
- Population
- Healthy adults
- Participants
- 120
- Ages
- 18–75
RCTEffects of echinacea on the frequency of upper respiratory tract symptoms: a randomized, double-blind, placebo-controlled trial2008n=90
In 58 hospital workers over 8 weeks, E. purpurea 6 capsules/day did not significantly reduce sick days (9 vs 14 days per person) compared with parsley placebo (p = 0.67).
- Effect
- No Benefit
- Duration
- 8 weeks
- Dose
- 6 capsules/day
- Population
- Women
- Participants
- 90
- Ages
- 18–65
RCTEchinacea purpurea and mucosal immunity2007n=32
In 32 subjects over 4 weeks, echinacea attenuated exercise-induced salivary IgA suppression and shortened reported URTI duration (3.4 vs 8.6 days) versus placebo, without reducing URTI incidence.
- Effect
- Benefit
- Duration
- 4 weeks
- Participants
- 32
RCTEfficacy and safety of echinacea in treating upper respiratory tract infections in children: a randomized controlled trial2003n=407
In 407 children (ages 2–11) with URIs over 4 months, E. purpurea did not reduce URI duration (9 days both groups) or severity, and was associated with increased rash (7.1% vs 2.7%, P = 0.008).
- Effect
- No Benefit
- Duration
- 4 months
- Population
- Children/adolescents
- Participants
- 407
- Ages
- 2–11
RCTA randomized controlled trial of the effect of fluid extract of Echinacea purpurea on the incidence and severity of colds and respiratory infections1999n=109
In 108 adults with frequent colds over 8 weeks, E. purpurea fluid extract (8 mL twice daily) did not significantly reduce cold incidence (65% vs 74%), duration (4.5 vs 6.5 days), or severity versus placebo.
- Effect
- No Benefit
- Duration
- 8 weeks
- Dose
- 4 mL twice/day
- Population
- Healthy adults
- Participants
- 109
RCTEchinacea root extracts for the prevention of upper respiratory tract infections: a double-blind, placebo-controlled randomized trial1998n=18
In 302 healthy adults over 12 weeks, echinacea root extracts did not significantly delay time to first URTI (66–69 vs 65 days) or reduce infection rate (~29–32% vs 37% placebo), though subjects perceived greater benefit.
- Effect
- No Benefit
- Duration
- 12 weeks
- Population
- Healthy adults
- Participants
- 18
RCTPlacebo-controlled, double-blind study of Echinaceae pallidae radix in upper respiratory tract infections1997
A 1997 placebo-controlled, double-blind study of Echinaceae pallidae radix for upper respiratory tract infections; outcome details were not available in the indexed abstract.
EleutheroView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Eleuthero has only been tested together with other herbs, so its effect alone is unknown.
- In people with common colds or upper respiratory tract infections, one study found that taking 30 mL per day of a liquid product called Kan Jang (which contains eleuthero, echinacea, and malabar nut) for 3–4 days did not make cough symptoms better than placebo or a standard medicine.
- Another study that was not blinded showed that taking the same product at a higher dose (30 mL three times daily for 6 days) improved cough, nasal congestion, and recovery time compared with bromhexine, although the study design makes the results less reliable.
- A capsule version of Kan Jang, containing eleuthero and andrographis, has also been studied.
- In people with uncomplicated colds, taking two capsules three times per day for 5 days helped shorten sick leave by about one day and increased the number of patients who felt recovered by day 3 compared with placebo.
Browse 3 studies
RCTEarly intervention with Kan Jang® to treat upper-respiratory tract infections: A randomized, quadruple-blind study2021n=179
In 179 URTI patients over 5 days, early Kan Jang (60 mg andrographolides/day) reduced sick leave by >21% (2.38 vs 3.02 days, p = 0.005) and improved all URTI symptoms from day 2 versus placebo.
- Effect
- Benefit
- Duration
- 5 days
- Dose
- 60 mg andrographolides/day
- Population
- URTI patients
- Participants
- 179
RCTAntitussive effect of a fixed combination of Justicia adhatoda, Echinacea purpurea and Eleutherococcus senticosus extracts in patients with acute upper respiratory tract infection: A comparative, randomized, double-blind, placebo-controlled study2015n=177
In 177 adults (18–65 years) with acute URI over 5 days, Kan Jang oral solution (30 mL/day) relieved cough comparably to bromhexine and better than placebo, with good tolerability.
- Effect
- Benefit
- Duration
- 5 days
- Dose
- 30 mL/day
- Population
- URTI patients
- Participants
- 177
- Ages
- 18–65
RCTRandomized trial of a fixed combination (KanJang) of herbal extracts containing Adhatoda vasica, Echinacea purpurea and Eleutherococcus senticosus in patients with upper respiratory tract infections2005
In URTI patients, KanJang (Adhatoda, echinacea, eleuthero) improved coughing, mucus discharge, nasal congestion, and sickness versus bromhexine, with recovery ~2 days faster.
- Effect
- Benefit
- Population
- URTI patients
QuercetinView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- Studies use quercetin together with vitamins like C and niacin, so it’s unclear if quercetin alone can help with colds or upper respiratory infections.
- Studies using 500 to 1000 mg of quercetin daily for 12 weeks showed no overall benefit in reducing how often or how badly people get sick.
- But in a group of healthy, active people over 40 years old, taking 1000 mg of quercetin reduced the severity of colds by 36% and the number of sick days by 31%.
- More research is needed to understand if quercetin helps certain groups of people.
Browse 2 studies
RCTQuercetin supplementation and upper respiratory tract infection: A randomized community clinical trial2010n=1,002
In 1002 adults over 12 weeks, 500 or 1000 mg/day quercetin did not reduce upper respiratory infection rates overall; the 1000 mg group had fewer sick days in fit adults over 40.
- Effect
- No Benefit
- Duration
- 12 weeks
- Dose
- 1000 mg/day
- Population
- Adults
- Participants
- 1,002
- Ages
- 18–85
RCTQuercetin reduces illness but not immune perturbations after intensive exercise2007n=40
In 40 trained cyclists over 3 weeks plus intensive exercise, 1000 mg/day quercetin did not alter exercise-induced immune changes but reduced upper respiratory tract infections (1/20 vs 9/20).
- Effect
- Benefit
- Duration
- 2 weeks
- Dose
- 1000 mg/day
- Population
- Athletes
- Participants
- 40
ResveratrolView supplement →
Reconsider purchase·★★★★★
How we scored this▸
- A small study in young children who wheeze after colds found that using a nose spray with resveratrol and water-soluble beta-glucan for 7 days lowered how long and often they wheezed but did not reduce how many colds they caught.
- It is not known which ingredient, or the combination, was responsible for the benefit.
Browse 1 study
RCTEffects of Nasal Solution Incorporating Resveratrol and Carboxymethyl-Β-Glucan in Preschool Non-Atopic Children with Wheezing2024n=19
In chronically stressed adults, a magnesium-B-vitamin-rhodiola-green tea supplement reduced stress scores versus placebo over 28 days.
- Effect
- Benefit
- Duration
- 7 days
- Population
- Children/adolescents
- Participants
- 19
Vitamin AView supplement →
Do not purchase·★★★★★
How we scored this▸
- Research in young children from some countries shows that taking vitamin A supplements does not clearly reduce how often they get colds or other upper respiratory infections.
- There isn’t enough information to say if vitamin A helps with cold symptoms either.
- More studies are needed.
Browse 1 study·1 meta-analysis
MetaOral vitamin A supplements to prevent acute upper respiratory tract infections in children up to seven years of age2024n=27,351
A meta-analysis of 27351 participants found that we are uncertain of the effect of vitamin A supplementation on the number of acute URTIs over two weeks (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.92 to 1.09; I 2 = 44%; 3 studies, 22,668 participants; low-certainty evidence).
- Effect
- No Benefit
- Population
- Women
- Participants
- 27,351
- Ages
- 0–7
Green TeaView supplement →
Do not purchase·★★★★★
How we scored this▸
- Early research suggests that gargling and drinking a small amount of green tea daily for four days is not as effective as a specific herbal lozenge made from labdanum (CYSTUS052) for relieving symptoms of common upper respiratory tract infections.
Browse 1 study
RCTEffect of CYSTUS052 and green tea on subjective symptoms in patients with infection of the upper respiratory tract2010n=300
In 300 patients with upper respiratory tract infection, CYSTUS052 and green tea were compared for symptom relief in a randomized double-blind study.
- Effect
- No Benefit
- Population
- Patients with upper respiratory tract infections
- Participants
- 300
Evidence visualised
Same ratings as above, aggregated so you can see coverage and imbalance.
| Supplement | DEX | Studies | Meta-analyses | Share |
|---|---|---|---|---|
| Vitamin D | ★★★★★68% | 14 | 1 | 35% |
| Echinacea | ★★★★★56% | 10 | 1 | 25% |
| American Ginseng | ★★★★★68% | 6 | 0 | 15% |
| Eleuthero | ★★★★★48% | 3 | 0 | 8% |
| Beta-Glucan | ★★★★★64% | 2 | 1 | 5% |
| Quercetin | ★★★★★44% | 2 | 0 | 5% |
| Green Tea | ★★★★★32% | 1 | 0 | 3% |
| Resveratrol | ★★★★★44% | 1 | 0 | 3% |
| Vitamin A | ★★★★★36% | 1 | 1 | 3% |