Know2eat

Astragalus

Astragalus membranaceus

Herbs & Botanicals

What astragalus may help with

Ranked by how strong the human evidence is — best supported first.

Best supportedImmune functionNot enough evidence· 2 sources

Then, in order

About Astragalus

The dried root of a legume used in Traditional Chinese Medicine as a qi tonic, usually as a decoction or a polysaccharide-rich extract. It is rarely used alone in its traditional context.

Nearly all Astragalus trials come from China, most as part of multi-herb formulas or alongside chemotherapy, and reviewers consistently flag poor reporting, small samples and probable publication bias in that literature. Because the traditional use is in blends, single-herb capsules sold in the West have very little that directly supports them.

Sold as
Root extract capsule, Dried root slices, Decoction, Tincture, Injectable (China only)
Standardised to
Sometimes standardised to astragalosides or to polysaccharide content — a product without this marker may not resemble what was studied.
Also known as
Huang qi, Milk vetch root, Astragalus propinquus

Regulation: An injectable Astragalus preparation is used in Chinese hospitals; nothing comparable is approved in the US or EU, where it is sold only as a supplement.

What the research used

The amounts, forms and durations published trials of Astragalus actually administered.

These are the amounts published trials administered — not a recommendation, and not a dose to copy. Trial participants were screened, supervised and given a characterised preparation. What is in a retail bottle is frequently not what was studied, and the amount that suits one person is not general advice.

  • Studied for Adjunct use in Chinese trials

    9–30 g

    Not enough

    Dried root as decoction, usually within a multi-herb formula · Weeks to months

    This is a traditional decoction range, not a dose for a Western capsule, and it was almost always given as part of a blend, which makes any effect impossible to attribute to Astragalus alone.

  • Studied for Standardised extract capsules

    500–2000 mg

    Not enough

    Root extract

    What retail products contain rather than what has been trialled. There is no established capsule dose for Astragalus in the Western supplement market.

This is general information about food, not medical advice. It cannot diagnose, treat or replace guidance from a clinician who knows your history.

When it was taken

Each window says whether a trial compared it against an alternative, or whether it is convention and pharmacology. Most timing advice is the second kind.

None of the timings below were directly compared in a trial. They reflect how the research happened to dose, or what the pharmacology implies — which is not the same as a timing being better.

  • Any time

    Not enough

    No timing pattern has been tested. Traditional use is as a cooked decoction with meals, which is culinary practice rather than pharmacology.

    Timing was not directly compared. This reflects convention or how the compound behaves in the body, not a trial showing this window works better.

The evidence in depth

Best supported: Not enough

What each association actually rests on, and the papers behind it. A rating describes the state of the research, not how promising the supplement sounds. How we rate evidence.

Immune function

Immune Health
Not enough evidence

Evidence is limited for Astragalus and immune outcomes in people. Laboratory work shows polysaccharides activate immune cells, but the human trials are small, mostly in Chinese-language journals and confounded by multi-herb formulas.

What may be going on: Astragalus polysaccharides stimulate macrophage and lymphocyte activity in cell culture.

Not enough evidence. Not enough human research to say anything useful yet.

View the 2 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Kidney and urinary function

Kidney & Urinary Health
Not enough evidence

Chinese trials in diabetic kidney disease report improvements in proteinuria, but reviewers rate the studies as low quality with a high risk of bias, and the preparations differ from Western capsules.

Not enough evidence. Not enough human research to say anything useful yet.

View the 4 sources

Deep research mode adds each paper’s own conclusion and stated limitations.

Things to know

Interactions, contraindications and dose limits, most serious first. Concentrated extracts interact with medication in ways the whole plant does not, so this section carries more weight here than it does on a food page.

  • Interaction

    Immunosuppressants

    Interacts withCiclosporin, tacrolimus, other immunosuppressants

    Astragalus is used specifically for its effects on immune cells, so it is generally contraindicated for people on ciclosporin, tacrolimus or other immunosuppressants after transplant, and questionable in active autoimmune disease.

  • Interaction

    Licorice in blend products

    Interacts withDiuretics, antihypertensives, digoxin

    Astragalus is usually sold and traditionally used in formulas that include licorice root as a harmoniser. Sustained licorice intake causes pseudohyperaldosteronism — sodium retention, potassium loss and raised blood pressure — so the other ingredients on the label matter as much as this one.

  • Worth knowing

    Heavy metals in imported preparations

    Testing of imported Chinese herbal products has repeatedly found lead, mercury and arsenic, and occasionally undeclared pharmaceuticals. Third-party testing is the only practical safeguard.

  • Interaction

    Anticoagulants and glucose-lowering drugs

    Interacts withWarfarin, antiplatelet drugs, insulin, sulfonylureas

    Possible additive effects on bleeding and on blood glucose have been raised in case reports and preclinical work, so combinations warrant a conversation with a prescriber.

  • Avoid

    Pregnancy

    Safety in pregnancy has not been established, and blend products carry ingredients whose pregnancy safety is separately unknown.

Evidence ratings on this page: 2 not enough evidence.

Supplements are sold in the US without pre-market review of efficacy or safety. Nothing on this page is a recommendation to take Astragalus, or a dose to follow.