The cold research on American ginseng comes from one extract, CVT-E002, sold in Canada as COLD-fX. In a 2005 trial of 323 adults, 400 mg a day over four months meant fewer colds and shorter ones. Two trials in older adults found fewer confirmed flu cases. The extract is made for its polysaccharides, and that is the form that delivered the winter benefit.
What a Polysaccharide Extract Is
Most American ginseng research is about ginsenosides, the compounds behind the blood sugar and memory findings. CVT-E002 is made from the root by a process that keeps the polysaccharides, long chains of sugar units, and the children's trial describes it as standardised to 80 percent of one polysaccharide family (Vohra 2008). A 2011 lab study of human immune cells found the extract matured dendritic cells, the cells that show invaders to the rest of the immune system, and pushed them toward an antiviral response (Ilarraza 2011). Where that is a dish result, it fits the idea that this extract works through immune signalling, which is the same signalling the winter trials put to work.
It Meant Fewer and Shorter Colds in Adults
A 2005 trial recruited 323 adults aged 18 to 65 in Edmonton, each with at least two colds in the previous year, and gave them two capsules a day of the extract or placebo for four months from the start of flu season (Predy 2005). Among the 279 who started treatment, the ginseng group averaged 0.68 colds per person against 0.93 on placebo. Only 10 percent of the ginseng group had two or more colds, against 23 percent on placebo. Colds were milder, with a total symptom score of 78 against 112, and shorter, with 10.8 symptom days against 16.5.
The extract cut the number of colds by about a quarter and the sick days by about a third, in people who catch colds often, and those shorter winters are the benefit.
It Meant Fewer Confirmed Flu Cases in Older Adults
Two placebo controlled trials in 2000 and 2001 enrolled 89 and 109 nursing home and assisted living residents, average age 81 and 83, most of them flu vaccinated, and gave them 200 mg of the extract twice a day for 8 or 12 weeks (McElhaney 2004). Pooled, lab confirmed flu struck 1 of 97 people on the extract against 7 of 101 on placebo. Adding confirmed RSV, a second winter virus, the count was 1 against 9. The authors reported no safety concerns, and those fewer confirmed cases are the strength of the extract in older adults.
In a small 2006 trial of 43 adults aged 65 and over living at home, with a flu shot after the first month, the first two months looked alike, and the last two months showed 32 percent of the extract group reporting a respiratory illness against 62 percent on placebo, with symptoms lasting 5.6 days against 12.6 (McElhaney 2006). No flu was circulating that season, so these were colds, and the shorter illnesses line up with the larger trials.
In Leukemia the Extract Raised Antiviral Antibodies
A 2012 trial of 293 people with early, untreated chronic lymphocytic leukemia, a cancer that weakens the immune system, ran from January to March (High 2012). Where the extract did no better than placebo on days with a respiratory illness and days with a severe one, it meant less moderate to severe sore throat, and more people on the extract showed a rise in antibodies against common viruses, 16 percent against 7. That antibody rise is the immune signal the extract is taken for.
In Children the Extract Was Well Tolerated
A 2008 trial in Edmonton followed 75 children aged 3 to 12 through a winter and randomised the 46 who caught a cold to a standard dose, a low dose or placebo (Vohra 2008). Where the trial was built to check safety, it found no serious adverse events and side effects matched across the arms, and that short course of the extract was well tolerated in children.
The Polysaccharide Extract Is the Form That Cut Colds
Where no trial has tested ground root, slices or tea against colds, every positive cold trial used CVT-E002, and that polysaccharide extract is what cut the colds and shortened them. Where a 2007 review of 14 trials of complementary treatments for flu still treated the wider field as unfinished, it counted the American ginseng extract among the few with more than one encouraging trial (Guo 2007). If colds are your reason for buying, the product that names this polysaccharide extract is the one those trials used.
How It Fits a Winter Routine
The adult and community trials used the same regimen: 400 mg a day, as two 200 mg capsules, every day for four months, started as cold and flu season began. The nursing home trials used the same daily dose over 8 to 12 weeks. In the 2006 trial the difference showed in months three and four, so the benefit rewards starting early and keeping going. The extract was also tested in athletes: 28 days at 400 mg a day produced no positive doping tests, so the winter dose stayed available to competitors (Goel 2004). For dose by goal, see American ginseng dosage for the 400 mg a day that meant fewer colds over four months.
What Users Report
Some people notice little change in a given winter, and many say they get through the season with fewer colds and shorter ones on the extract. That lines up with the trial drop from 0.93 to 0.68 colds per person and from 16.5 to 10.8 symptom days. These reports describe the same shorter winter the extract produced.
Safety Notes
Across the cold trials, side effects matched placebo in adults, in older adults and in children aged 3 to 12. Where you take warfarin or diabetes medicines, or you have an immune condition or take medicines that act on the immune system, talk with your doctor, and in these trials the extract was tolerated like placebo. See American ginseng side effects.
For the rest of what the research supports, see American ginseng benefits. At 400 mg a day through the cold season, the polysaccharide extract meant fewer colds and fewer days sick.
References
- Predy GN et al. 2005. Efficacy of an extract of North American ginseng containing poly-furanosyl-pyranosyl-saccharides for preventing upper respiratory tract infections: a randomized controlled trial. CMAJ.
- McElhaney JE et al. 2004. A placebo-controlled trial of a proprietary extract of North American ginseng (CVT-E002) to prevent acute respiratory illness in institutionalized older adults. J Am Geriatr Soc.
- McElhaney JE et al. 2006. Efficacy of COLD-fX in the prevention of respiratory symptoms in community-dwelling adults: a randomized, double-blinded, placebo controlled trial. J Altern Complement Med.
- High KP et al. 2012. A randomized, controlled trial of Panax quinquefolius extract (CVT-E002) to reduce respiratory infection in patients with chronic lymphocytic leukemia. J Support Oncol.
- Vohra S et al. 2008. Safety 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 schedules. Pediatrics.
- Ilarraza R et al. 2011. Human dendritic cells promote an antiviral immune response when stimulated by CVT-E002. J Pharm Pharmacol.
- Guo R et al. 2007. Complementary medicine for treating or preventing influenza or influenza-like illness. Am J Med.
- Goel DP et al. 2004. Doping-control urinalysis of a ginseng extract, Cold-FX, in athletes. Int J Sport Nutr Exerc Metab.
Nothing here is medical advice. If you take prescription medication, talk with your doctor before adding American ginseng.
