Supplement analysis backed by scientific evidence · PT

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Moderate evidenceGeneral health

Panax Ginseng

Modest but reasonably consistent evidence that ginseng reduces subjective fatigue; essentially no evidence it improves physical performance, and no convincing evidence for cognition. The erectile dysfunction trials are positive but of low methodological quality.

What the science says

  • Reduces fatigue Moderate evidence

    A meta-analysis of 12 RCTs (630 participants) pooled 4 fatigue trials and found a significant benefit (SMD 0.34, 95% CI 0.16-0.52). The authors themselves cautioned that the number of trials and sample sizes were small, so the effect is best described as real but modest and not firmly established.

  • Does not improve physical performance Moderate evidence

    The same meta-analysis pooled 8 RCTs of exercise performance and found nothing: SMD -0.01 (95% CI -0.29 to 0.27). Despite heavy marketing to athletes, ginseng has no demonstrated ergogenic effect.

  • Cognitive enhancement Limited evidence

    A Cochrane review identified 9 double-blind placebo-controlled trials, but only 5 had extractable data and heterogeneity in dose, duration and outcome measures made pooling impossible. The reviewers concluded there is a lack of convincing evidence for a cognitive-enhancing effect in healthy people and no high-quality evidence in dementia.

  • Erectile dysfunction Limited evidence

    A systematic review of 7 RCTs of Korean red ginseng found a significant pooled effect versus placebo (n = 349, risk ratio 2.40, 95% CI 1.65-3.51) for improvement in erectile function. However, average methodological quality by Jadad score was low and the individual trials were small, so this is suggestive rather than conclusive.

Dosage & safety

Studied doseGeneral and fatigue trials: 200-400 mg/day of extract standardized to 2-8% ginsenosides, or 1-3 g/day of dried root, for 4-12 weeks. Erectile dysfunction trials typically used Korean red ginseng 600-1000 mg three times daily (1.8-3 g/day) for 8-12 weeks.
SafetyInsomnia is the most frequently reported effect, along with headache, nervousness and GI upset. Ginseng can lower blood glucose, which is additive with insulin and sulfonylureas. It has been shown to reduce the anticoagulant effect of warfarin (falling INR), and case reports describe headache, tremor and mania when combined with the MAOI phenelzine. Ginsenosides show weak estrogen-like activity in vitro, so caution is usually advised in hormone-sensitive cancers, though clinical data are lacking. Discontinue at least a week before surgery because of effects on glucose and platelets. Not banned in sport, but ginseng is a recurring target for adulteration and heavy-metal contamination, so third-party tested products matter.

Scientific references

Where to buy

Swanson Vitamins, Full Spectrum® Korean Red Ginseng Root, 400 mg, 90 Capsules

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