Korean red ginseng (Panax ginseng) improves glucose and insulin regulation in well-controlled, type 2 diabetes: results of a randomized, double-blind, placebo-controlled study of efficacy and safety.

BACKGROUND AND AIM: To address the paucity of randomized clinical studies assessing ginseng on long-term outcomes in type 2 diabetes, we assessed the clinical antidiabetic efficacy and safety of 12 weeks of supplementation with a Korean red ginseng (KRG) preparation, dose, and mode of administration, selected from an acute, clinical, screening model.

METHODS AND RESULTS: Nineteen participants with well-controlled type 2 diabetes (sex: 11 M:8 F, age: 64+/-2 years, BMI: 28.9+/-1.4 kg/m(2), HbA(1c): 6.5%) completed the study. Using a double-blind, randomized, crossover design, each participant received the selected KRG preparation (rootlets) and placebo at the selected dose (2 g/meal=6 g/day) and mode of administration (preprandial oral agent [-40 min]) for 12 weeks as an adjunct to their usual anti-diabetic therapy (diet and/or medications). Outcomes included measures of efficacy (HbA1c and fasting- and 75-g oral glucose tolerance test [OGTT]-plasma glucose [PG], plasma insulin [PI], and insulin sensitivity index [ISI] indices); safety (liver, kidney, haemostatic, and blood-pressure function); and compliance (returned capsules, diet-records, and body-weight). There was no change in the primary endpoint, HbA(1c). The participants, however, remained well-controlled (HbA1c=6.5%) throughout. The selected KRG treatment also decreased 75 g-OGTT-PG indices by 8-11% and fasting-PI and 75 g-OGTT-PI indices by 33-38% and increased fasting-ISI (homeostasis model assessment [HOMA]) and 75 g-OGTT-ISI by 33%, compared with placebo (P<0.05). Safety and compliance outcomes remained unchanged.

CONCLUSIONS: Although clinical efficacy, as assessed by HbA1c, was not demonstrated, 12 weeks of supplementation with the selected KRG treatment maintained good glycemic control and improved PG and PI regulation safely beyond usual therapy in people with well-controlled type 2 diabetes. Further investigation with similarly selected KRG treatments may yield clinical efficacy.