It is uncertain whether ashwagandha affects immune health by reducing stress, but chronic stress tends to suppress immune function.[1][2][3] Ashwagandha’s general immunomodulatory capability (at a dosage of 60–500 mg daily for 1–4 weeks) has been explored through direct assessment of immune parameters (immunoglobulin A, immunoglobulin M, immunoglobulin G, cytokines, natural killer cells, and lymphocytes) with encouraging results for fighting infection.[4][5][6][7][8][9] These findings, however, still require replication with more robust methodological approaches.
When examining the prevention or treatment of respiratory infection, studies tended to take a more complete ayurvedic approach by using ashwagandha alongside additional therapies and/or herbs. Although these studies have promising initial results, the methods and interventions used were variable, and more research is needed.[5][10][11][8][9]
A few clinical trials in adults with and without health conditions appear to suggest that antioxidant and anti-inflammatory properties provide the main effects on immune health. Ashwagandha use (500–5,000 mg daily for 8–12 weeks) correlated with increases in antioxidants and decreases in oxidation markers such as malondialdehyde, along with improvements in exercise recovery, fertility, lung function, oxygen uptake, perceived stress, and quality of life.[12][13][14] Several studies have also explored ashwagandha (500–1,000 mg daily for 8–12 weeks) for treating arthritis, where anti-inflammatory capacity was the proposed mechanism of action, though this mechanism and effect still has yet to be confirmed.[15][16][17]