Ginseng (Panax)

Panax ginseng contains active compounds called ginsenosides and other constituents that act as adaptogens (supporting stress resilience) and have antioxidant, anti-inflammatory, immune-modulating, mitochondrial and neurotransmitter-modulating effects — all of which are plausible mechanisms for reducing fatigue and improving mental focus. Several preclinical and clinical reviews conclude these mechanisms can translate to reduced fatigue scores in people. Frontiers

Key mechanistic points from the reviews and trials:

• Antioxidant effects: trials measured lower markers of oxidative stress (ROS, MDA) after Panax use; this is one proposed pathway by which fatigue is relieved. PLOS
• Neurotransmitter / HPA axis effects: animal and some human data show effects on neurotransmitters (serotonin, dopamine, GABA) and stress-response systems that may improve mental fatigue and concentration. Frontiers
• Energy / mitochondrial support and immune modulation: preclinical work and biomarkers (e.g., better heart-rate recovery, metabolic markers) support a biologic plausibility for reducing both physical and mental fatigue. Frontiers

What clinical trials actually used (so you have concrete, evidence-based dosing & durations):

• PLOS ONE (Kim et al., 2013) — a randomized, double-blind RCT in people with idiopathic chronic fatigue: Panax ginseng ethanol extract 1 g/day or 2 g/day (given as four 250 mg capsules twice daily at 09:00 and 19:00) for 4 weeks. The 2 g/day group had statistically significant reductions in visual analogue fatigue scores and improvements in mental fatigue; antioxidant markers (ROS, MDA, GSH) changed in ways consistent with benefit. PLOS
• Korean Red Ginseng trials (multiple; e.g., Sung et al., 2019 and related KRG RCTs) — trials in chronic-fatigue populations commonly used around 2–3 g/day of (Korean) red ginseng, often for 4–6 weeks; some trials reported improved fatigue scores and objective markers. (Example trial: 3 g KRG/day for 6 weeks in a randomized, double-blind design). Europe PMC

Practical, cautious instructions that align with published practice and safety resources:

• Typical clinical/trial ranges: ~1–3 g/day of whole root equivalent or an extract providing the study-level ginsenoside content (many studies used 1 g–3 g/day). Some standardized extracts used 200–400 mg/day of a concentrated extract in other settings — but the CFS trials above used gram-level whole/extract doses. PLOS
• Administration timing: because ginseng can be mildly stimulating, take in the morning and early afternoon rather than late evening to reduce insomnia risk (PLOS ONE dosing split at 09:00 and 19:00 in that trial; many clinicians prefer morning dosing). PLOS
• Duration to assess effect: most RCTs ran 4–6 weeks; consider a trial of at least 4 weeks to see an effect (unless adverse effects occur). PLOS
• Start low, go slow: start at the lower end (e.g., ~1 g/day or a lower standardized extract dose) for several weeks and increase only if tolerated and needed. Monitor symptoms, blood pressure, sleep, and blood glucose if diabetic. PLOS
• Product quality: use a reputable, third-party tested product that states ginsenoside content and species (Panax ginseng / Korean red ginseng) — supplement regulation varies by country. Verywell Health

Randomized clinical trials

• Kim H-G et al., PLoS ONE, 2013 — Antifatigue Effects of Panax ginseng: RCT in 90 subjects with idiopathic chronic fatigue; used 1 g/day and 2 g/day for 4 weeks and reported improvements (not all outcomes reached significance vs placebo but mental fatigue and some VAS results improved; antioxidant markers were favorable). PLOS
• Sung WS et al., (2019) / Korean red ginseng RCTs — randomized, double-blind trials in chronic fatigue using ~3 g/day KRG for several weeks reporting improvements in fatigue scales and objective markers in some cohorts. (Multiple KRG antifatigue trials exist in the literature). Europe PMC

Systematic reviews / meta-analyses

• Frontiers in Pharmacology, 2020 (Jin et al.) — systematic review of Panax ginseng and compounds for fatigue: pooled evidence from several RCTs (eight RCTs, 678 participants) and many animal studies; concluded P. ginseng and compounds showed superiority over placebo on fatigue scales and had a similar rate of adverse effects to placebo, and summarized plausible mechanisms (oxidative stress, neurotransmitters, immune effects). Frontiers
• Systematic review focused on ginseng for CFS (2021/2022 reviews) — reviews that specifically surveyed trials in CFS/ICF concluded that direct evidence is limited but promising, and more high-quality, larger RCTs are needed. (See specialized systematic reviews and Europe PMC summary). SAGE Journals

Preclinical / mechanism reviews

• The Frontiers review (2020) also compiles preclinical data describing antioxidant, mitochondrial, neurotransmitter, and immune pathways that could explain antifatigue effects. Frontiers

Summary: there are well-conducted small RCTs and systematic reviews showing signal of benefit (improved fatigue scores, some objective markers) but larger, longer trials in well-characterized CFS/ME populations are still limited. The balance of evidence is promising but not definitive. PLOS