Ren Shen

The principal bioactive markers of ginseng. They are broadly adaptogenic, immunomodulatory and neuroprotective. Panaxadiol-type saponins such as Rb1 tend to be CNS-depressant and hypotensive, whereas panaxatriol-type saponins such as Rg1 are CNS-stimulant and mildly hypertensive, which is thought to underlie ginseng's balancing (adaptogenic) reputation. Rg3 shows the most studied anti-tumour and anti-angiogenic activity.

Immunostimulant, promoting macrophage and NK-cell activity and cytokine release; the panaxan fraction contributes much of ginseng's documented hypoglycaemic activity in animal models.

Antiplatelet and cytotoxic to cultured tumour cell lines; contribute to ginseng's inhibitory effect on platelet aggregation and thromboxane formation.

Reported to lower blood glucose in experimental models, reinforcing the polysaccharide-mediated hypoglycaemic effect.

Antioxidant; a Maillard-type product generated during the steaming that converts white ginseng into red ginseng and a marker of that processing.

Contributes the characteristic aroma; minor anti-inflammatory and spasmolytic activity.

The peeled or unpeeled root is simply dried. This milder form tonifies Qi and generates fluids and is preferred when there is heat or Yin deficiency. Because ginseng is costly and its actives are heat-stable but the classic caution is to preserve potency, the sliced root is typically decocted separately (ling jian) over low heat and the strained liquid added to the finished decoction; a common dose is 3-9 g (up to 15-30 g for collapse/rescue).

The fresh root is steamed and then dried, turning it reddish and generating maltol and specific ginsenosides such as Rg3. Red ginseng is warmer and more strongly tonifying to Yang and Qi, favoured for cold, deficient and collapse patterns. Prepared and dosed as for white ginseng, usually decocted separately and combined.

Finely ground root taken directly by swallowing with warm water, 1-2 g once or twice daily, to conserve the expensive material and for chronic Qi tonification.

Reviewed 65 RCTs of Panax ginseng across domains including psychomotor and physical performance, glucose metabolism, respiratory disease, erectile dysfunction and quality of life. The authors concluded that many trials suggest benefit but methodological quality was often limited, so definitive efficacy claims require larger rigorous trials.

Meta-analysis of 16 RCTs found that ginseng significantly improved fasting blood glucose compared with control in people with and without diabetes, though effects on HbA1c and fasting insulin did not reach significance. The overall evidence supports a modest glucose-lowering effect.

This is the most tonifying herb. Rescues qi.