Panax Ginseng

Panax ginseng is the root of a slow-growing perennial native to Korea and northeastern China. Roots are typically harvested at four to six years, which is much of why genuine ginseng is expensive. The genus name comes from the Greek for all-healing.

The active compounds are ginsenosides, of which more than a hundred have been identified. Extracts are standardised to total ginsenoside content, commonly 2 to 8 per cent.

The detail that matters and is almost never explained: individual ginsenosides have opposing effects. Rg1 tends to be stimulating, Rb1 tends to be calming, and the ratio between them determines how a given extract actually feels. Red ginseng is steamed before drying, which alters the ginsenoside profile again. American ginseng, Panax quinquefolius, is a different species with a different profile and is generally considered the calmer of the two.

Ginseng is classed as an adaptogen, a term describing compounds proposed to improve resistance to stressors generally rather than acting on one target. The most cited route is modulation of the stress hormone axis.

Ginsenosides also influence nitric oxide production, which affects blood flow, and have been reported to act on neurotransmitter systems involved in alertness and mood.

An important practical point is that ginsenosides are extensively transformed by gut bacteria before absorption. Individual differences in gut microbiota therefore affect what actually reaches circulation, which may partly explain why responses to ginseng vary so much between people.

Fatigue is the most consistently supported area. Systematic reviews have generally reported reductions in self-reported fatigue, with effects clearer in people who are run down than in the well-rested.

Cognitive research has produced mixed but leaning-positive results for attention and working memory, often from acute dosing studies. Effects are modest.

Exercise performance findings are inconsistent, with many trials showing no meaningful benefit to endurance or strength. There is a body of research on blood sugar markers with reasonably favourable results, though that is not why most people buy it. The recurring caveat across this literature is that extracts differ so much that pooling results is genuinely difficult.

Generally well tolerated. The most commonly reported effects are difficulty sleeping, headache, digestive upset and jitteriness, most of which relate to taking too much or taking it too late in the day.

Ginseng can lower blood sugar and has a mild effect on how readily blood clots, so check with your doctor before use if you take regular medication.

Some ginsenosides show oestrogenic activity in laboratory models, which is worth mentioning to your doctor if your hormones are being monitored or managed.