Astragalus (Astragalus membranaceus)

Astragalus membranaceus / mongholicus
Evidence Level
Moderate
2 Clinical Trials
5 Documented Benefits
3/5 Evidence Score

Astragalus (Huang Qi) is one of the most important tonic herbs in Traditional Chinese Medicine, used for over 2,000 years as a fundamental immune-modulating and adaptogenic herb. Its primary bioactives — astragalus polysaccharides (APS) and cycloastragenol/astragaloside IV — demonstrate immunomodulatory effects through multiple pathways, and astragaloside IV has generated significant longevity research interest for its ability to activate telomerase — making astragalus one of very few natural substances with clinical evidence for telomere length preservation.

Studied Dose 9–30 g/day dried root (traditional TCM dose); standardized extract: 400–1,200 mg/day; astragaloside IV: 16–32 mg/day; TA-65®: 5–10 mg/day cycloastragenol
Active Compound Astragalus polysaccharides (APS), cycloastragenol, and astragaloside IV — standardized extract ≥0.5% astragaloside IV; TA-65® (TA Sciences) is the most studied cycloastragenol form

Immune system modulation and enhancement

Astragalus polysaccharides activate macrophages, NK cells, T-cells, and B-cells through multiple pattern recognition receptor pathways. Clinical studies show improved vaccine response, reduced upper respiratory infection frequency, and enhanced NK cell activity in immunocompromised and healthy elderly populations.

Telomerase activation and telomere preservation

Cycloastragenol and astragaloside IV activate telomerase reverse transcriptase (hTERT) — the enzyme that extends telomeres. A 12-month TA-65® study showed significant reduction in the percentage of critically short telomeres and improvements in immune aging biomarkers, positioning astragalus as one of very few natural telomerase activators with human clinical data.

Cardiovascular and kidney protection

Astragalus polysaccharides demonstrate protective effects in cardiac and renal tissue — reducing ischemia-reperfusion injury, improving cardiac function post-infarction, and reducing proteinuria in diabetic nephropathy. Multiple Chinese clinical trials (though often lower quality) support cardiovascular adjunct applications.

Blood sugar regulation

APS improves insulin sensitivity, reduces fasting blood glucose, and protects pancreatic beta cells from oxidative damage. Clinical studies in type 2 diabetic patients show significant improvements in glycemic markers with astragalus supplementation alongside conventional therapy.

Adaptogenic and anti-aging properties

Astragalus reduces cortisol levels under stress, improves energy and vitality, and has been used as a fundamental anti-aging herb in TCM. The combination of immune modulation, telomerase activation, antioxidant activity, and metabolic benefits makes astragalus one of the most comprehensive longevity-supporting botanicals.

1

TLR-4 and Dectin-1 immune receptor activation

Astragalus polysaccharides bind TLR-4 and Dectin-1 pattern recognition receptors on macrophages and dendritic cells, activating NF-κB-dependent innate immune responses including cytokine production, NK cell activation, and dendritic cell maturation. This innate immune priming enhances both infection defense and vaccine response efficacy.

2

Telomerase reverse transcriptase (hTERT) activation

Cycloastragenol activates hTERT transcription by binding and activating protein kinase C (PKC) signaling cascades that upregulate the TERT gene promoter. Astragaloside IV may act through similar mechanisms. Telomerase activation extends critically short telomeres in immune cells, potentially reversing one aspect of cellular immunosenescence.

3

PI3K/Akt/mTOR pathway modulation for cellular protection

Astragalosides modulate the PI3K/Akt survival pathway in cardiac, renal, and immune cells — reducing apoptosis in stressed cells, improving mitochondrial membrane potential, and supporting cellular energy metabolism under hypoxic or inflammatory conditions.

1
TA-65® Cycloastragenol and Immune Aging Biomarkers — Clinical Study
PubMed

Single-arm, open-label study of TA-65® (5–10 mg/day cycloastragenol) in 114 healthy adults aged 53–87 for 12 months.

114 healthy adults aged 53–87. 12-month supplementation.

TA-65® significantly reduced the proportion of critically short telomeres in peripheral blood lymphocytes. Improvements in senescent CD8+CD28- T-cell proportion observed. First human study demonstrating telomere elongation with a natural compound. NK cell activity improved.

2
Astragalus and Upper Respiratory Infections — Systematic Review
PubMed

Systematic review of 22 clinical studies examining astragalus for respiratory infection prevention.

Multiple clinical studies, diverse populations.

Astragalus supplementation significantly reduced frequency of upper respiratory infections and shortened duration of illness in most studies. Immune enhancement markers (NK cells, IgG, IgA) improved. Supports traditional TCM use for immune protection during cold season.

Common Potential side effects

Generally very well tolerated at standard supplemental doses
Mild GI effects rarely at high doses of whole herb powder
Immunostimulating effects — caution in autoimmune conditions and transplant patients

Important Drug interactions

Immunosuppressants (cyclosporine, tacrolimus) — astragalus stimulates immune function; may reduce immunosuppressant efficacy; avoid in transplant patients
Cyclophosphamide — astragalus may modulate immunosuppressive effects of this chemotherapy agent; complex interaction
Antidiabetic medications — additive glucose-lowering; monitor blood sugar
Anticoagulants — mild effects reported; monitor with warfarin