NOW Supplements, Astragalus (Astragalus membranaceus) 500 mg, supports Immune System. Other Ingredients: Cellulose (capsule), Cellulose Powder, Silica and Magnesium Stearate (vegetable source). Not manufactured with yeast, wheat, gluten, soy, milk, egg, fish, shellfish or tree nut ingredients. Produced in a GMP facility that processes other ingredients containing these allergens. Astragalus 500 mg Veg Capsules. Astragalus root (huang qi) has been used as a popular herbal tonic in China for many centuries. Some of the known active components include flavonoids, free amino acids, trace minerals and polyphenols.