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Korean Red Ginseng Boosts the Immune System of Healthy Participants


Reviewed: Hyun SH, Ahn HY, Kim HJ, et al. Immuno-enhancement effects of Korean red ginseng in healthy adults: A randomized, double-blind, placebo-controlled trial. J Ginseng Res. January 2021;45(1):191-198. doi: 10.1016/j.jgr.2020.08.003. 

A decline in immune function reduces the body’s ability to heal. The South Korean Ministry of Food and Drug Safety has recognized Korean red ginseng (KRG; Panax ginseng, Araliaceae), also known as Asian ginseng, for its antioxidant properties and role in improving immunity, fatigue, blood circulation, memory, and the health of postmenopausal women. KRG’s immune system activation has been studied in vitro and in vivo. In human clinical studies, KRG is reported to have beneficial effects in people with acute respiratory diseases and on immune cell count and cytokines in people with cancer. In this randomized, double-blind, placebo-controlled trial, the authors examined the effects of two months of KRG consumption on the immune cells of healthy participants who had a recent upper respiratory infection.

The study was conducted in South Korea. Eligible participants were healthy males and females aged 40-65 years whose white blood cell (WBC) count was “below 6.0 × 10/mL.”* Included participants reported having an upper respiratory infection within the preceding month.

At the first visit, the participants’ demographic information, medical history, and medication use were recorded. The KRG group and placebo group each included 50 participants, who were instructed to take two tablets twice daily for eight weeks. The total daily dose of 2 g of KRG contained ginsenosides Rb1 (8.03 mg/g), Rc (3.29 mg/g), Rb2 (2.80 mg/g), Rg3 (2.50 mg/g), Rf (1.47 mg/g), Re (1.29 mg/g), Rg1 (1.18 mg/g), and Rd (1.0 mg/g). The placebo tablets contained corn (Zea mays, Poaceae) starch, cellulose, and KRG flavoring and color.

Primary outcome measures were changes in T cells, B cells, and WBCs, which are components of the body’s immune system, after eight weeks of intervention. Secondary measures included changes in cytokines (tumor necrosis factor-alpha, interferon-gamma, interleukin [IL]-2, and IL-4), WBC differential count, and incidence of upper respiratory infections. One participant in the KRG group withdrew from the trial, leaving 99 participants in the final analysis.

After eight weeks of treatment, the number of T cells was significantly greater in the KRG group compared with the placebo group (P = 0.0191); the changes in the number of T cells from baseline to the end of the trial were also significantly greater in the KRG group compared with the placebo group (P = 0.0348). The subtypes of T cells (helper T cells and cytotoxic T cells) increased significantly in the KRG group compared with the placebo group during the trial (P < 0.05 for all). In addition, the increase of the B cell distribution in the KRG group was significantly greater than that in the placebo group after eight weeks (P = 0.0061). WBCs also significantly increased in the KRG group compared with the placebo group (P = 0.0490).

No significant between-group differences were observed in changes in cytokines, the WBC differential count, or the incidence of upper respiratory infections. No significant adverse effects were reported, and safety outcome measures were unremarkable.

The authors concluded that “KRG boosts the immune system through an increase in T cells, B cells, and WBCs, and that it is safe according to the study’s safety evaluation.” The authors declared no conflicts of interest.

* 6.0 × 10/μL, or 60 WBCs/μL, is a dangerously low WBC count and likely erroneous. The authors later describe WBC counts in terms of “× 108/μL,” which corresponds to WBC counts in the hundreds of millions, which have not been reported in humans. Normal WBC counts typically range between 4,500 and 11,000 WBCs/μL.1 HerbalGram editors attempted to contact the authors to clarify these discrepancies but received no response.


  1. Normal blood counts. Leukemia and Lymphoma Society website. Available at: Accessed September 26, 2021.