Ashwagandha (Withania somnifera) is an adaptogen working on the endocrine system and the Hypo-Pituitary-Axis (HPA). The Sanskrit implies it gives the user the strength and stamina of a horse- with some doctors saying that taking it in the morning will allow you to run 20 miles while taking it at night will allow you to sleep like a baby. I am sure that is an exaggeration (at least in my case), but you get the idea.
It is most well known to decrease fatigue [1], allow you to handle stress more effectively, increase strength and stamina, increase libido, improve memory and clarity [2], and produce restful sleep when needed [3]. The various conditions it has been used for include arthritis (it is anti-inflammatory) [4, 5], chronic lung condition, [6] immune deficiency [7], hypertension [8], autoimmune problems [9], hypothyroidism [10], and many others.
With ashwagandha being an adaptogen, it is said to be an extremely effective anti-stress herb. Research on mice has shown it to increase both endurance and speed while swimming, and increase muscle mass. This study shows ashwagandha may be used for both anti-stress activity as well as anabolic muscle growth [1]. By inhibiting NFκB cells, ashwagandha can lower stress and help those suffering from cystic fibrosis [6].
For patients on immunosuppressive drugs ashwagandha may act as an adjunct to minimize the side effects and increase ones immune response when needed. Studies show patients on ashwagandha while on immunosuppressive drugs showed decreased myelosuppression, and an increase in hemoglobin concentration, red blood cell count, white blood cell count, platelet count, and body weight. An immuno-stimulatory effect was also observed [7].
Animal studies have shown it may be useful in treating drug-induced dyskinesia [11]. In one animal study, ashwagandha increased brain levels of superoxide dismutase, catalase and glutathione peroxidase [12]. This could easily be the mechanism of how it improves cognition, memory and perhaps longevity. The increased superoxide dismutase can be used to break down histamine, helping reduce allergy symptoms. Other studies have shown it increases acetylcholine receptor activity, stimulates the growth of axons and dendrites and has GABA-like activity [13, 14]. In most cases we prefer it to GABA because it is a “whole natural food” and has many complementary properties.