Ginseng, along with Gotu Kola and FoTi, are cornerstone recommendations for hair growth in both ancient systems of Traditional Chinese Medicine (TCM) and Ayurvedic Medicine from India.
Recent published research on Ginseng Extract has shown it has incredibly reliable effects as a hair growth stimulating agent in both topical and systemic forms. Studies on both cellular function and oral supplementation have shown a consistently positive effect on hair growth in both those with Androgenetic Alopecia and auto-immune variants such as Alopecia Areata. Significantly, not a single published study has shown either a negative or even negligible effect; the data on Ginseng’s effect on hair growth and have been uniformly positive.
A published literature review by the same title showed that Ginseng’s stimulating effect on hair growth come through a multitude of mechanisms.

Hair-Growth Potential of Ginseng and Its Major Metabolites: A Review on Its Molecular Mechanisms
 In one particular study, published in the Journal of Ginseng Research, 40 cohorts with androgenic alopecia were recruited and randomly divided into the experimental (20 patients) and control (20 patients) groups.The intervention group took Korean red ginseng extract (3,000 mg/day) for 24 weeks while the controls took a placebo.
Pre and post intervention hair counts, thickness, and density were assessed.Patient satisfaction was determined through a questionnaire, and clinical photographs were rated by dermatologists. The result of the study showed that  Ginseng Extract  effectively increased hair density and thickness. In another study, mice were orally administered either Ginseng Extract or finasteride.
In contrast to the finasteride-treated group, the Ginseng -treated group exhibited 20 percent higher hair-growth rates as evidenced by increased number of hair follicles, epidermal thickness, and proportion of follicles in the anagen phase Ginseng Extract contains bioactive components, known as ginsenosides.Dr Choi stated “There has been mounting evidence suggesting that Ginseng and its major bioactive constituents, ginsenosides, promote hair growth.”They may function in this regard by enhancing proliferation of dermal papilla.
Ginseng Extract also prevents hair loss via modulation of specific cell-signaling pathways, and increases the number of Dermal Papilla Cells, by preventing the programmed cell death, seen in Androgenetic Alopecia. Ginseng Extract has additionally been shown to increase Vascular Endothelial Growth Factor (VEGF) stimulates the peripheral growth of blood vessels, including the scalp. 
On a possibly related note, Ginseng Extract has been demonstrated to reduce hypertension in a similar way to oral Minoxidil, which has also been established to stimulate some degree of hair growth. It also has well established adaptogenic stress modulating effects, both protecting and supporting adrenal function, and regulation of cortisol, the stress hormone. Several studies have demonstrated that elevated cortisol is present in all forms of hair loss, including Alopecia Areata, Telogen Effluvium, and Androgenetic Alopecia.
So there are multiple pathways by which Ginseng can slow aging and stimulate hair growth.  
There are an infinite number of Ginseng products on the market. Our recommended Ginseng Formulation, Asian Energy Boost combines Cordyceps and Panax ginseng that has been naturally fermented, a process shown to increase absorption of the active compound—Compound K (Ginsenosides metabolite)—by over 15-fold. Evidence indicates that ginseng supports ATP production in the mitochondria. Studies have shown that this extract promotes hair growth, both physical and mental energy, and improves cognitive performance. Cordyceps, like Ginseng has been shown to balance cortisol and stress hormones.