I have mentioned Ginseng in several posts, but have not done one doing a deep dive into it. Asian Ginseng has a reported benefit (40%) on the surveys and sSupplementation helped 56% in one PubMed study (2005)
- “Fatigue among subjects assigned to either placebo or Siberian ginseng was substantially reduced during the study, but differences between treatment groups were not statistically significant in the full sample.”  – so the effect is small (if at all).
- “Ratings on the Visual Analogue Scale (VAS) revealed a reduction in pain (of Fibromyalgia) in the P. ginseng group (p < .0001), an improvement in fatigue (p < .0001) and an improvement in sleep (p < .001), with respect to baseline characteristics, but there were no differences between the three groups. With respect to anxiety, improvements occurred in the P. ginseng group compared to baseline (p < .0001); P. ginseng reduced the number of tender points and improved patients’ quality of life (using the Fibromyalgia Impact Questionnaire – FIQ); however, there were no differences between groups. “
- “consumption of white or red Korean ginseng (WG or RG) powder significantly increased the number of total bacteria and Lactobacillus strains compared to the control group.” 
The main impact of ginseng appears to be on coagulation (and thus improved oxygen delivery resulting in less pain caused by cellular hypoxia).
- ” herbal medicines that inhibit platelet function (e.g., garlic, ginseng, or ginkgo)” 
- The influence of herbal medicine on platelet function and coagulation: a narrative review . “ginseng, green tea, and St John’s wort were found to have potential interactions with warfarin.”
- Study on improving blood flow with Korean red ginseng substances using digital infrared thermal imaging and Doppler sonography: randomized, double blind, placebo-controlled clinical trial with parallel design.
The amount of information on ginseng is less than ideal. It appears to have only a limited impact on the microbiome. I ascribe most of its positive effects are due to improving blood flow.
Cost to benefit appear low, so I would place it low on desired herbs and supplements.There are other items that are cheaper, just as effective on improving blood flow and more effective in shifting the microbiome.