Astragalus membranaceus (Fisch.) Bunge, syn. Astragalus mongholicus · herb
Evidence tier: limited
Builds long term immune resilience and has adaptogenic properties
Astragalus polysaccharides and saponins, principally astragaloside IV, modulate immune cell activity in laboratory and animal models, and the polysaccharide fraction activates macrophages. This is genuine, replicated preclinical pharmacology. It has not been shown to translate into a measurable immune benefit in humans in a well controlled trial, which is the gap between what astragalus does in a dish and what it is sold to do in a person.
Limited. Astragalus has an enormous preclinical literature, a 2,000 year place in traditional Chinese medicine, and almost no trustworthy human evidence. Memorial Sloan Kettering's About Herbs entry is the plainest read available: the immunomodulating and antioxidant properties are shown in preclinical work, but 'the majority of studies included in these analyses were limited by poor methodology', and while some small studies suggest benefit for cancer related fatigue and chemotherapy side effects, 'larger, well designed trials are needed to confirm the findings'. The clinical trial base is overwhelmingly Chinese, small, and frequently unblinded or uncontrolled; recent reviews state that the therapeutic potential is strongly supported by extensive PRECLINICAL evidence while the lack of robust human clinical evidence greatly constrains clinical translation, with existing studies limited by small sample sizes and inadequate blinding and controls. The specific human results that do exist are narrow and mostly in disease populations: intravenous astragalus improved one facet of immune function in dialysis patients, and early Chinese trials suggest possible benefit in chronic viral hepatitis. Intravenous administration in kidney failure patients is not the product a consumer buys. There is no good placebo controlled evidence that oral astragalus prevents colds, shortens infections, or does anything measurable to immunity in healthy adults, which is what it is sold for. The safety picture is the part that deserves more weight than the seed gives it: because astragalus is an immunoSTIMULANT, MSK flags that it can reduce the effectiveness of immunosuppressant drugs, may increase bleeding risk with warfarin, may add to the effect of antihypertensives, and has possible estrogenic activity relevant to hormone sensitive cancers.
No authority establishes one. Practice in the supplement literature runs 500 to 1,500 mg of dried root extract daily, or decoctions of 9 to 30 g of dried root in the traditional Chinese medicine setting. These figures come from practice and tradition, not from dose finding trials.
Daily, long term. Best taken in the morning.
Well tolerated in healthy adults at standard doses. Limited safety data in pregnancy and lactation, use with caution. Contraindicated with immunosuppressant drugs.
Pregnancy: caution
Breastfeeding: caution
Active compounds: astragalus polysaccharides, astragaloside IV, cycloastragenol, formononetin, calycosin
Remedies using Astragalus · Browse by body system · Check it against what you take
*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.