Astragalus root extract
Also known as: Astragalus root, Huang Qi, Astragalus membranaceus
Overview
Astragalus root extract is derived from the dried root of Astragalus membranaceus, a leguminous plant traditionally used in Chinese medicine. It is primarily recognized for its immunomodulatory, antioxidant, and anti-inflammatory properties. The extract contains bioactive compounds such as polysaccharides, triterpenoid saponins (e.g., astragalosides), and flavonoids. Research indicates its potential benefits in chronic kidney disease (CKD), as an adjunct therapy in cancer, and for general immune support. While numerous clinical trials and systematic reviews exist, many studies have methodological limitations, suggesting a need for more rigorous research to fully establish its efficacy and safety across all purported uses.
Benefits
Astragalus has shown several evidence-based benefits. In renal function, preparations containing astragalus have demonstrated statistically significant improvements in estimated glomerular filtration rate (eGFR) and reductions in serum creatinine in patients with mild to moderate CKD. A retrospective study observed eGFR improvement after approximately 3.4 months of supplementation (median 3 g/day), and a meta-analysis confirmed lower serum creatinine when combined with Western medicine. As an adjunct in cancer therapy, a meta-analysis of colorectal cancer patients suggested that astragalus combined with chemotherapy improved tumor response rates, quality of life, and reduced chemotherapy side effects, although the included RCTs had low methodological quality. It also exhibits immunomodulatory effects by stimulating immunocompetent lymphocytes and cytokine production. Other reported effects include antioxidant, anti-inflammatory, cardioprotective, osteoprotective, and neuroprotective properties, though clinical evidence for these is less robust.
How it works
Astragalus primarily exerts its effects through its bioactive compounds, particularly polysaccharides and saponins. These compounds modulate immune function by activating Toll-like receptor 4, which subsequently triggers downstream MAPK and NF-kB signaling pathways. This activation leads to enhanced cytokine production and increased activity of lymphocytes, thereby boosting the immune response. Its antioxidant effects are achieved by scavenging reactive oxygen species and upregulating the body's endogenous antioxidant enzymes. Astragaloside IV, a prominent saponin, contributes anti-inflammatory and angiogenic properties. The bioavailability of astragalus varies depending on the preparation, with sublingual delivery potentially offering faster immune effects compared to oral forms.
Side effects
Astragalus is generally considered safe, with clinical studies reporting few serious adverse events. The most common side effects, occurring in over 5% of users, include mild fatigue, malaise, and headache, which are likely associated with its immune-activating properties. While no major drug interactions have been conclusively documented, caution is advised when astragalus is used concurrently with immunosuppressants or chemotherapy, and consultation with a healthcare professional is recommended. Contraindications may include autoimmune diseases where immune stimulation could be detrimental, although specific data are limited. Furthermore, there is insufficient safety data for special populations such as pregnant women and children, and its use in these groups is not recommended without medical supervision.
Dosage
Effective dosages of astragalus root extract in clinical studies typically range around 3 grams per day, administered orally or as part of herbal formulations. The duration of treatment varies, with renal benefits often observed after approximately 2-3 months of consistent use. While there is no established maximum safe dose, traditional use and clinical trials suggest that doses up to 10 grams per day are generally well-tolerated. The form of administration can influence absorption; for instance, sublingual delivery may enhance absorption and potentially lead to faster immune effects. Co-administration with other herbs, such as Angelica sinensis, may also improve absorption and efficacy.
FAQs
Is astragalus safe during chemotherapy?
Some evidence suggests astragalus may reduce chemotherapy side effects and improve immune function, but research quality is limited. Always consult your oncologist before use.
How soon do benefits appear?
Improvements in renal function may be observed after 2-3 months of consistent use, while immune-related effects can potentially manifest sooner.
Can astragalus be used for autoimmune diseases?
Caution is advised due to its immune-stimulating properties. There is insufficient data to recommend its use in autoimmune conditions; consult a healthcare professional.
Are there any serious side effects?
Serious side effects are rare. Most reported adverse effects are mild, such as fatigue, malaise, and headache, likely due to immune activation.
Research Sources
- https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2022.775798/full – This retrospective chart review (n=37) found that astragalus supplementation (median 3 g/day) significantly improved eGFR in patients with mild-to-moderate CKD after approximately 3.4 months. The study suggests renoprotective effects but is limited by its small sample size and retrospective design.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6700271/ – This meta-analysis of 1,409 colorectal cancer patients indicated that astragalus combined with chemotherapy improved tumor response rates, quality of life, and reduced chemotherapy side effects. However, the authors noted that the included RCTs had low methodological quality and a high risk of bias, warranting cautious interpretation.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11885490/ – This systematic review and meta-analysis of multiple RCTs in CKD patients found that astragalus combined with Western medicine significantly lowered serum creatinine levels (SMD=0.62, p<0.001). The study highlights astragalus's potential renoprotective role but acknowledges high heterogeneity and varied study quality among the included trials.
- https://ascopost.com/issues/october-10-2020/astragalus/ – This summary of systematic reviews and clinical trials discusses astragalus's immunomodulatory, antioxidant, and anticancer effects, noting its potential to improve chemotherapy side effects in cancer patients. It points out the lack of large, high-quality RCTs and mentions some immune-related side effects.
- https://www.mskcc.org/cancer-care/integrative-medicine/herbs/astragalus – This source provides an overview of astragalus, detailing its traditional uses, active compounds, and mechanisms of action, including its role in immune modulation via Toll-like receptor 4 and MAPK/NF-kB pathways. It also discusses the varying bioavailability based on preparation and potential synergistic effects with other compounds.
