Astragalus has a long history in Chinese medicine as a complementary approach to hepatitis, cancer, and other conditions. Today in the western world, it has been rediscovered as a “super herb”, but most of its uses still lack solid clinical evidence. This post reveals Astragalus benefits, dosage, and side effects.
What is Astragalus?
Astragalus is a large genus of around 3,000 species belonging to the legume family Fabaceae. This plant is a native to the temperate regions in the Northern hemisphere. Common names include milkvetch (most species), locoweed (some species in North America) and goat’s thorn.
Astragalus root is a staple of Traditional Chinese Medicine (TCM), where it is also known as Huang Qi.
It is also used as a “Qi tonifier” in the oriental system of medicine [1].
Most Astragalus supplements contain Astragalus membranaceus and are marketed as life-prolonging extracts for human use.
The root is the only part of the plant used medicinally and is usually harvested from 4-year old plants. Herbalists call astragalus an “adaptogen”.
Snapshot
Proponents:
- Boosts the Immune system
- Helps combat infections
- Has antioxidant and anti-inflammatory effects
- Protects the kidneys and heart
- May have anticancer effects
Skeptics:
- Interacts with immunosuppressants
- May not be suitable for autoimmune conditions
- People report headaches and insomnia from higher doses
- Most conditions require intravenous application
Potentially Active Chemical Constituents
Polysaccharides are the most important functional constituents in Astragalus and responsible for the antimicrobial, antiviral and anti-inflammatory capabilities of this herb [2].
It also has several saponins, called Astragalosides (I to X) which are known for their ability to lower cholesterol and boost the immune system [1].
Astragalus also contains flavonoids which show antioxidative qualities and help prevent heart disease and immunodeficiency. Other constituents include amino acids, folic acid, etc and minerals like selenium, zinc, and copper [3].
Traditional Uses
In the Chinese medicinal system, Astragalus is indicated for spleen deficiency symptoms like diarrhea, fatigue, spontaneous sweating and lack of appetite.
Other traditional indications include wasting disorders (a process in which disease causes muscle and fat tissue to “waste” away), night sweats, chronic ulcerations and sores, numbness and paralysis of the limbs and edema [4].
Astragalus is also traditionally used as an antidiarrheal or a laxative and for the treatment of common cold [2].
Health Benefits of Astragalus
Possibly Effective:
1) Heart Disease
Intravenous injection of Astragalus significantly improved heart function in two studies of 134 patients with congestive heart failure (CHF) [5, 6].
In another study Astragalus (Astragaloside IV) injected into 19 patients with Congestive heart failure reduced symptoms of chest distress and dyspnea (shortness of breath) in 15/19 patients. There was also a significant improvement in heart function [7, 1].
92 patients with ischemic heart disease treated with Astragalus experienced significant relief from angina (chest pain) and heart rate improvement. In another study on angina pectoris, 20 patients given Astragalus for two weeks had an increase in heart function [7].
Astragalus (A. membranaceus injection) combined with conventional treatment appeared to improve the treatment of viral myocarditis (heart inflammation) in six different studies. However, the authors pointed to limitations such as small sample size, limited number of trials, and high risk of bias [8].
A. mongholicus, when given to rats with high lipids, resulted in a significant decline in the levels of total cholesterol, triglycerides, and LDL, and an increase in HDL cholesterol levels in the blood [9].
In obese rats, researchers noticed the potential of astragalus to improve the function of the heart and blood vessels [10].
Astragalus has the potential to improve heart function and help with different types of heart disease, but well-designed clinical trials should verify these effects. The fact that most studies used intravenous forms is a significant limitation.
2) Immune Response
In one study, 8 grams of Astragalus given orally to 14 healthy volunteers for 2 months significantly stimulated white blood cells. In another study, Astragalus extract given to healthy adults for 20 days increased blood IgM, IgE, and cAMP [11].
An herbal tincture of Astragalus stimulated CD4 and CD8 T-cells and induced the production of CD69 in human subjects [12].
Viral myocarditis patients showed enhanced T3, T4 and T4/T3 cell ratios suggesting an increased immune response when given an extract of Astragalus orally [7].
One Chinese trial found that astragalus could decrease overactive immune function in people with systemic lupus erythematosus (SLE), an autoimmune disease [13].
Astragalus polysaccharides (APS) activated B cells and macrophages in mouse and human tumor cell lines [14].
APS suppressed regulatory T-cells (Treg) and initiated the CD4+T-cell-mediated immunity in mice with P. aeruginosa infection [15].
In preliminary clinical research, astragalus has shown immune-supporting effects by stimulating macrophage and natural killer cell activity and inhibiting T-helper cell type 2 cytokines [16].
The effects of astragalus on the immune response look promising, but the lack of solid clinical evidence prevents us from drawing conclusions.
3) Kidney Function
High-dose Astragalus injection used together with cyclophosphamide (CTX) was effective in decreasing infection rates and improving immune and kidney function in 43 patients with lupus nephritis (inflammation of the kidneys) [17].
According to one study, Astragalus injection improved kidney function in 67 patients with IgA nephropathy (Immunoglobulin A buildup in the kidneys) [18].
In a meta-analysis of five clinical trials (429 patients), Astragalus injection showed a protective effect in high blood pressure patients with kidney damage [19].
In another meta-analysis (25 studies with 1,804 patients), it could also improve kidney function in patients with diabetic nephropathy.
Scientists have observed the potential of Astragalus to reduce kidney inflammation, improve their function, and protect them against toxic drugs in multiple animal studies [20, 7, 21]
Clinical studies discussed above used injected Astragalus; oral consumption likely wouldn’t produce the same effects.
4) Diabetes
In China, Astragalus is the most popular herb for diabetes management [22, 23].
According to a meta-analysis of 13 studies with 1,054 participants, both oral and intravenous administration can lower glucose levels, when added to standard treatment. Oral consumption also significantly reduced hemoglobin A1c, a measure of long-term blood glucose levels [24].
However, the authors pointed to the limited quality of the included trials and suggested further investigation.
Astragalus could effectively control blood glucose, reduce the free radicals, and promote the antioxidative activity in 84 pregnant women with gestational diabetes [25].
In lab animals, scientists examined the potential of Astragalus polysaccharide (APS) to reduce insulin resistance and ER stress induced by high glucose [26].
Astragalus improved fasting blood glucose levels and kidney function in diabetic rat models [20].
APS could increase pancreatic beta-cell mass in type 1 diabetic mice [27].
5) Complementary Cancer Treatment
The findings discussed below stem from preliminary clinical research and animal studies. They should guide further investigation but shouldn’t be interpreted as supportive of the anticancer effects until more research is done. Astragalus can’t prevent or treat cancer; it may only be considered as a complementary approach to cancer treatment by your doctor.
According to a meta-analysis of 34 studies with 2,815 cancer patients, Astragalus-based Chinese herbal medicine combined with chemotherapy may improve survival, increase tumor response, and reduce chemotherapy toxicity. The authors underlined the low quality of the included trials and suggested further research [16].
The addition of Astragalus to standard treatment (chemo) significantly improved quality of life and reduced the symptoms in 136 patients with advanced non-small cell lung cancer (NSCLC) [28].
In 120 cancer patients, the addition of Astragalus to chemotherapy could “inhibit the development of tumors, decrease the toxic-adverse effect of chemotherapy, elevate the immune function of the organism and improve the quality of life in patients”, according to study authors [29].
Astragalus polysaccharide (APS) could promote the production and maturation of cancer-fighting immune cells in the samples from chronic myelogenous leukemia patients [30].
Astragalus saponins (AST) suppressed the growth of colon cancer in mice with equal efficiency and fewer side effects, compared with chemotherapy [31].
In test tubes, this plant showed inhibitory effects against liver and stomach cancer cells, but this doesn’t imply the same effect in living organisms [32, 33].
Further, well-designed clinical trials are needed to verify the potential of Astragalus to improve cancer treatment.
6) Anemia and Other Blood Disorders
Therapy with Astragalus root was effective and safe in 57 children with beta-thalassemia. It improved hemoglobin and red blood cells while causing no major side effects [34].
Astragalus injections improved treatment effectiveness and stimulated the production of blood components in 60 patients with chronic aplastic anemia [35].
Astragalus (60 g) as part of a Chinese herbal medicine reduced the severity of aplastic anemia in 62 patients, but this study lacked a control group [36].
In 115 patients, Astragalus was effective against leukopenia (a reduction in the number of white blood cells), especially in higher doses (2×15 mg daily). Once again, the lack of placebo control prevents us from drawing solid conclusions [37].
Researchers observed the potential of this herb to protect and stimulate bone marrow cells in anemic mice [38].
Insufficient Evidence:
No valid clinical evidence supports the use of astragalus for any of the conditions in this section. Below is a summary of up-to-date animal studies, cell-based research, or low-quality clinical trials which should spark further investigation. However, you shouldn’t interpret them as supportive of any health benefit.
7) Respiratory Problems
Astragalus played a role in preventing the recurrence of asthma in a study of 90 children. A combination of astragalus and standard treatment showed even better effects [39].
According to two low-quality clinical trials, Astragalus may reduce the incidence of Upper Respiratory Tract Infection (URTI) in children with nephrotic syndrome [40].
Astragalus (Astragaloside IV) could prevent the development of chronic asthma and reduce asthma attacks in mice [41].
8) Brain Protection
Astragalus could enhance functional recovery in 78 stroke patients [42].
Extract of this herb improves nerve injury in studies on mice [43, 44].
In rats, active components of Astragalus reduced iron overload as seen in Alzheimer’s disease [45].
Animal and Cellular Research (Lacking Evidence)
No clinical evidence supports the use of astragalus for any of the conditions listed in this section. Below is a summary of the existing animal and cell-based studies. They should guide further investigational efforts but should not be interpreted as supportive of any health benefit.
9) Inflammation
Both oral and colonic Astragalus (A. membranaceus) treatments exhibited significant protection against colitis (colon inflammation) in rats [46].
Water and alcoholic extracts of Astragalus (A. hamosus) given orally produced a highly significant anti-inflammatory effect in rats in another study [47].
10) Cellular Aging
TA-65Ⓡ is a natural telomerase activator purified from the root of Astragalus. The use of this natural product in animals showed a decline in the percent of old cytotoxic T cells and natural killer cells [48].
In the absence of telomerase, telomeres shorten with time and stress, contributing to aging and disease.
Isomers extracted from Astragalus slowed down telomere shortening rate, reduced DNA damage and improved DNA repair ability (various factors which are responsible for the delay in aging) [49].
11) Infections
Astragalus (A. membranaceus) stimulated immune cells (Th1) of 27 children with recurrent tonsillitis (tonsil inflammation) [50].
It is used traditionally as an immune stimulant in treating and preventing colds and upper respiratory tract infections.
Viral:
Astragalus polysaccharide had immunomodulatory effects on cells exposed to Porcine reproductive and respiratory syndrome virus (PRRSV) and Classical Swine fever virus (CSFV) [51].
Astragalus polysaccharide (APS) treatment reduced H9N2 Avian Influenza virus replication and stimulated the immune response in animal and cell-based trials. In China, APS is widely used as an immune adjuvant [52].
A. membranaceus has an inhibitory effect on herpes simplex virus type 1(HSV-1) [53].
Astragalus inhibited viral replication in the heart muscle tissue of mice infected with Coxsackie B-3 virus [7].
Oral administration of Astragalus root extract to mice infected with Japanese encephalitis virus increased their survival rate by 30-40% [54].
Astragalus polysaccharide (APS) may also be efficient against Epstein Barr virus [55].
Sulfated Astragalus polysaccharide (sAPS) had activity against the cellular infectivity of infectious bursal disease virus, and the sulfated modification enhanced its antiviral activity [56].
APS has an inhibitory effect on the replication of the hepatitis B virus (HBV) [57].
Other:
In test tubes, astragalus showed antibacterial activity against Shigella dysenteriae, Streptococcus hemolyticus, Diplococcus pneumonia and Staphylococcus aureus [7].
It showed significant antifungal activity against Trichophyton verrucosum in a guinea pig model of dermatophytosis [58].
12) Wound Healing
Topical application of Astragalus (gum tragacanth) accelerated skin wound contraction and healing in rats [59].
Astragalus (astragaloside IV) could promote ulcerated wound healing in cultured mouse keratinocytes [60].
In animal and cellular studies, scientists observed would healing and anti-scar effects of Astragalus (Astragaloside IV) [61].
13) Convulsions
Researchers observed powerful anticonvulsant effects of Astragalus (A. mongholicus) root in mice [62].
Mechanism: Anticonvulsant effects may be mediated by its protective action against oxidative damage and improving mitochondrial dysfunction [62].
14) Male Fertility
Astragalus demonstrated a significant stimulatory effect and increased the motility of human sperm cells in lab studies [7].
In male mice, A. membranaceus improved relative testes weight and sperm parameters and reduced reproductive toxicity [63].
It could significantly reduce the apoptosis of spermatogenic cells, decrease the level of fat peroxidation and protect glutathione activity in rat testes [64].
15) Gut Protection
In test tubes, Astragalus (A.membranaceus) could strengthen the movement and muscle tonus in the intestine [65].
A high dose had a protective effect on bleeding injury of the intestinal mucosa [66].
Astragalus Polysaccharide (APS) effectively reduces colitis (colon inflammation) in rats [67].
16) Liver Protection
Oral administration of an alcoholic extract of Astragalus (A. membranaceus) root reduced the liver injury in mice [68].
Intake of Traditional Chinese Medicine (Astragalus membranaceus, Morus alba, Crataegus pinnatifida, Alisma Orientale, Salvia miltiorrhiza, and Pueraria lobata) may be useful in preventing and improving fatty liver induced by alcohol, according to animal studies [69].
17) Fatigue
Astragalus (Radix Astragali), as a component of a Chinese herbal medicine, reduced fatigue by increasing the oxygen uptake in 12 athletes [70].
Astragalus could significantly reduce exercise-induced fatigue in oxygen-deprived mice and improved exercise performance in trained mice [3, 71].
Flavonoids from this herb reduced chronic fatigue syndrome in rats [72].
18) Tissue Scarring (Fibrosis)
Astragalus as a component of a Chinese herb “Danggui Buxue tang” (DBTG) had an inhibitory effect on lung and kidney scarring in rats [73, 74, 75, 76].
A decoction of Astragalus exerted a significant therapeutic effect on biliary scarring in rats [77, 78].
According to another study on rats, Astragalus might be effective against peritoneal dialysis (PD)-induced peritoneal tissue scarring [79].
Astragalus Safety, Side Effects, and Precautions
Astragalus is considered safe for most adults and usually doesn’t cause any major side effects [80].
Pregnant and lactating women should not take this herb.
One study suggested that oral administration of A.membranaceus may lead to an increase in CA19-9 and the formation of liver and kidney cysts [81].
Some Astragalus species may be toxic; few of them contain the alkaloid swainsonine which may cause “locoism” in livestock. Few species contain potentially toxic levels of selenium.
Drug Interactions
Supplement-drug interactions can be dangerous and, in rare cases, even life-threatening. Always consult your doctor before supplementing and let him know about all drugs and supplements you are using or considering.
It may interact with medications that suppress the immune system, such as corticosteroids and drugs taken by organ transplant recipients. It may also affect blood sugar levels and blood pressure, and thus potentially interact with drugs for these indications [80].
According to preliminary research, astragalus may have diuretic properties. In theory, this effect might reduce excretion and increase the levels of lithium [82].
Astragalus Supplements
Astragalus supplements have not been approved by the FDA for medical use. In general, regulatory bodies aren’t assuring the quality, safety, and efficacy of supplements. Speak with your doctor before supplementing.
The below doses may not apply to you personally. If your doctor suggests using a grape seed extract supplement, work with them to find the optimal dosage according to your health condition and other factors.
Dosage
For most health conditions, astragalus was injected under strict medical supervision. Oral consumption may not produce the same effects.
General oral doses:
Heart disease: 2.25-7.5 g, twice daily for 14-30 days.
Astragalus root: About 1-4 grams of freshly dried root.
Powdered root capsules: 250-500 milligrams, two capsules 3x a day.
Tincture: 3-6 ml (½ – 1 tsp), 3x a day.
Textbooks on Chinese herbs recommend taking 9-15 g of the crude herb per day in decoction form. A decoction is made by boiling the root in water for a few minutes and then brewing the tea [13].
Synergies
According to preliminary research, Astragalus may yield even better results with the following plants:
- Goji berries [83]
- Elderberry fruit (Sambucus nigra) [84]
- Chinese ginseng (Panax notoginseng) [85]
- Red sage (Salvia miltiorrhiza) [86]
- Female ginseng (Angelica sinensis) [87]
- Fo-ti (Polygonum multiflorum) [88]
Well-designed clinical trials haven’t approved the safety and efficacy of these combinations.
