astragalus

Astragalus (Astragalus membranaceus) is a flowering plant whose root has long been used in traditional Chinese medicine, often in combination with other herbs. It is sometimes classified as an "adaptogen," a term for a substance theorized to help the body resist physical, environmental, and emotional stress, though that classification reflects tradition rather than proven effect.

According to the NIH's NCCIH, there is not sufficient reliable scientific evidence to know whether astragalus is useful for any health condition. Recent reviews in areas such as type 2 diabetes, immune function, and kidney disease have reported some improvements, but NCCIH notes the underlying studies were generally small, of low quality, and prone to bias, so the findings are not conclusive. Promotion for uses like allergic rhinitis, asthma, chronic fatigue, and wound healing is not backed by adequate efficacy data.

There is no established standard dose. NCCIH notes that taking up to 60 grams per day for as long as 4 months does not seem to cause adverse effects, but this is not a recommendation of an effective amount. Because evidence is limited and herbs can interact with medicines, talk with your health care provider before starting astragalus, especially if you take any medication or have a health condition.

Astragalus may be safe for most adults when taken by mouth at studied amounts, though a thorough safety evaluation has not been done. There is not enough reliable information to know whether it is safe applied to the skin. Little is known about its safety during pregnancy or breastfeeding, and some animal research suggests it may be toxic to the fetus during pregnancy, so it is prudent to avoid it if pregnant. People with autoimmune diseases should avoid astragalus because it might worsen their symptoms.

NCCIH does not describe specific common adverse effects at the amounts studied (up to 60 grams daily for up to 4 months), but it cautions that a thorough safety evaluation of astragalus has not been done, and that there is not enough reliable information about topical (skin) use. The main flagged concern is its potential effect on the immune system rather than typical short-term side effects.

Astragalus may interact with medications that suppress the immune system, so it should be used cautiously, if at all, by people taking immunosuppressants. More broadly, NCCIH advises that if you take any medicine, you should talk with your health care provider before using astragalus or other herbal products, because some herbs and medicines can interact in harmful ways.