Also known as: Astragalus membranaceus, Huang Qi, Milk vetch, Astragaloside IV, Cycloastragenol
BotanicalEmerging evidence
A root used as a foundational tonic in traditional Chinese practice, more recently taken up by the longevity category for its effects on telomerase. The traditional and modern uses barely overlap.
Typical dose
500.0–2000.0 mg per day
Daily with food; traditionally taken over extended periods
What it is
Astragalus membranaceus is a legume native to northern China and Mongolia. The root, known as huang qi, is one of the most widely used preparations in traditional Chinese practice, typically as a tonic taken over long periods rather than acutely.
Compounds of interest include polysaccharides, flavonoids, and the saponins astragaloside IV and cycloastragenol. Extracts are standardised to one of these, most often astragaloside IV.
Cycloastragenol is the reason astragalus appears in the longevity category, and highly concentrated cycloastragenol products sit at a very different price point from ordinary root extract. Whether that premium is justified by the evidence is a fair question, and the answer is currently unclear.
How it works
Astragalus polysaccharides interact with immune cell receptors, which underpins its traditional positioning as a strengthening tonic.
The longevity interest rests on telomerase. Telomeres are the protective caps on chromosome ends that shorten with each cell division, and telomerase is the enzyme that maintains them. Cycloastragenol has been shown in laboratory work to activate telomerase.
Whether activating telomerase in a person produces any benefit is an open question rather than an established one, and it is not without theoretical complications, since cells that divide indefinitely are not universally desirable. This is an area where laboratory findings have run considerably ahead of human evidence.
What the evidence shows
Human evidence is limited. Most research is preclinical, covering immune, antioxidant and metabolic endpoints in cell and animal models.
There is a body of research from China on astragalus as part of multi-herb formulas in supervised settings, which is difficult to interpret for a single-ingredient supplement.
For the telomerase application specifically, human data is sparse. A small number of studies have reported changes in telomere length measures, but sample sizes are small, and the leap from a laboratory enzyme finding to a meaningful outcome in a person taking capsules has not been made. Treat this as an interesting area of research rather than a demonstrated benefit.
Dosing
Common range is 500-2,000 mg daily of root extract. Traditional preparation uses considerably more root in decoction form over long periods.
Cycloastragenol products are used at far lower amounts, typically a few milligrams, and should not be compared to root extract on weight.
Astragalus is traditionally taken continuously over months rather than in short bursts, which fits its positioning as a tonic. Take with food. Where the goal is the longevity angle rather than general use, be clear-eyed that you are buying into an unproven proposition at a significant premium.
At a glance
Common forms
Root extract, Astragaloside IV standardised, Cycloastragenol, Whole root powder, Decoction
Half-life / duration
Not well characterised; traditional use is long-term rather than acute
Timing
Daily with food; traditionally taken over extended periods
Competition status
Permitted — not on the WADA Prohibited List
Category
Botanical
Safety and side effects
Generally well tolerated at typical doses, with digestive upset the occasional complaint. It has a long record of traditional use, which offers reasonable reassurance at customary intakes.
Astragalus has immune-modulating activity, so check with your doctor before use if your immune system is being managed. It may also affect blood sugar and blood pressure.
Long-term human safety data at concentrated extract doses, and particularly for cycloastragenol, is limited.
Who should avoid it
Speak to your doctor before use if your immune system is being managed, if your blood sugar or blood pressure is being monitored, or if you take regular medication. Not established for use in pregnancy or breastfeeding. Long-term safety at concentrated extract doses is not established.
This entry is provided for information only. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Consult a qualified healthcare professional before use if you are pregnant, breastfeeding, taking medication or under medical supervision.
