What Is Astragalus?

Astragalus (Astragalus membranaceous) is an Asian plant that's been used medicinally for centuries. In Chinese, it's called huang qi, which means "yellow life energy." 

That's because the root is yellow and it is considered to be one of the most useful herbs in Traditional Chinese Medicine (TCM). However, Western research has yet to provide much evidence of its effectiveness.

This article looks at the claims about astragalus, what research says about them, potential dangers, safe and unsafe dosages, and how to shop for and store astragalus.

Uses of Astragalus

In TCM, astragalus is used for a variety of ailments. Scientists have begun studying it as a potential treatment for:

• Immune support
• Heart disease
• Complications of diabetes
• Chronic obstructive pulmonary disease (COPD)

In addition, some people use astragalus for constipation, allergies, the common cold, or upper respiratory infections.

However, before anyone can say for sure whether it's safe and effective for any medicinal use, researchers need to conduct more and higher-quality human studies. Research to this point should be considered preliminary.

Immune Support

A 2016 study looked at oral (by mouth) astragalus for preventing acute respiratory tract infections in children. Researchers concluded there was inadequate evidence to support this use.

Astragalus membranaceus was also studied in a small group of adult rowers to evaluate the impact on the immune system after exercise. The small, double-blinded study used doses of 500 milligrams (mg) during an intensive 6-week training camp.

Compared to the control group, the treatment group had better recovery. However, the study was too small to draw conclusions about whether it changes how the immune system works.

Heart Disease

Researchers have studied astragalus for various heart conditions. It may have a diuretic effect, which could lower blood pressure and cause blood vessels to relax.

A small study on astragalus for post-menopausal high blood pressure (hypertension) and metabolic syndrome suggested some benefits. The study compared the regular treatment alone to the regular treatment plus either 5 grams or 10 grams of astragalus per day.

After one year, the group getting 10 grams of astragalus had better diastolic (bottom number) blood pressure, waist circumference, and waist-to-hip ratios. While this is promising, larger studies are still needed.

A systematic review of studies on Astragalus membranaceous in humans and animals suggested it may help treat a heart condition called viral myocarditis. Astragalus lowered harmful heart enzymes and levels of troponin (a protein that indicates heart damage) in the treatment group.

Researchers concluded that astragalus is an:

• Antiviral
• Anti-inflammatory
• Antifibrotic (prevents the thickening and scarring of damaged connective tissue)

Again, more research is needed before astragalus can be recommended for treating viral myocarditis.

Complications of Diabetes: Diabetic Kidney Disease

Astragalus has been studied for use in diabetic kidney disease.

A systematic review and meta-analysis of studies suggested that both oral and injectable astragalus may reduce urine protein loss and serum creatinine levels in diabetic kidney disease.

Due to limited high-quality studies, more research is needed.

Chronic Obstructive Pulmonary Disease (COPD)

In studies of chronic obstructive pulmonary disease (COPD), an inhaled form of astragalus improved measures of breathing including forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC) 14 days after treatment.

Researchers reported that it also improved the immune function of people with acute exacerbation of COPD. However, more research is needed before recommending astragalus for COPD.

What Are the Side Effects of Astragalus?

Even "natural" products can cause unwanted side effects, and astragalus is no exception.

Common Side Effects

Some common side effects of astragalus may include:

• Rashes
• Itching
• Nausea and diarrhea
• Headache
• Fatigue
• Runny nose
  

Long-term side effects are unknown, as studies beyond four months long haven't been done.

Severe Side Effects

Severe side effects from astragalus are likely rare. Talk with your healthcare provider about any questions that you may have.

Precautions

Astragalus may cause immunomodulation (a change or increase in your body's immune response). You shouldn't use astragalus without a healthcare practitioner's recommendation if you have autoimmune diseases such as:

• Crohn's disease
• Multiple sclerosis
• Psoriasis
• Rheumatoid arthritis
• Type 1 diabetes
• Systemic lupus erythematosus (SLE)

You also shouldn't use astragalus if you've had an organ transplant.

Also, keep in mind that supplement safety generally isn't established for children, people with chronic conditions, those taking prescription medications, or during pregnancy and breastfeeding.

Dosage: How Much Astragalus Should I Take?

Researchers don't have enough scientific evidence to define an appropriate dose of astragalus for various age groups or conditions.

The appropriate dose for you may depend on many factors, including your age, sex, and medical history. Talk to your healthcare provider for personalized advice and always tell them what herbs or supplements you're taking.

What Happens If I Take Too Much Astragalus?

So far, researchers haven't established a recommended daily intake or upper tolerable limit for astragalus. Taking too much increases your risk of side effects.

If you believe you've taken too much astragalus, contact your healthcare provider immediately for further guidance or get emergency medical attention.

Interactions

Astragalus may interact badly with several classes of medications.

• Antivirals: Theoretically, astragalus may change the effectiveness of antiviral medications such as acyclovir and amantadine.
• Blood pressure medications: Astragalus can lower blood pressure. It could cause dangerously low blood pressure if combined with hypertension medications.
• Cancer treatments: In mice, astragalus suppresses estrogen, so it may reduce the effectiveness of certain cancer treatments that target estrogen levels.
• Diuretics and drugs affected by diuretics: Astragalus' possible diuretic effects may impact how well your body processes certain drugs. It may also interact with other diuretics.
• Immunomodulators: Astragalus has immune effects. It may interfere with drugs that suppress or stimulate the immune system.
  

Astragalus may also interact with other herbs and supplements that have effects similar effects to the drugs mentioned above.

Be sure you carefully read the ingredient list and nutrition facts panel of a supplement so you know what's in it and at what levels. Always review this information with your healthcare provider and discuss any potential interactions with foods, medications, or other supplements. 

Sources of Astragalus & What to Look For

In TCM, astragalus is usually made into a decoction. The roots are boiled in water, then removed. It's often combined with other herbs, such as ginseng.

Astragalus can be found in supplement form at most health food stores. You may see the raw root in some locations, but more typically the herb is sold in capsule, liquid, or tablet form.

If you choose to buy astragalus or any supplement, the National Institutes of Health (NIH) recommends that you look for a Supplement Facts label on the product that you buy. This label will contain vital information about active ingredients and other added ingredients (like fillers, binders, and flavorings).

Astragalus Supplements

You can find astragalus supplements in multiple forms at health food stores or online. Forms of astragalus include tablets, capsules, liquid, or powders. Some astragalus supplements are derived from the root, while others may come from root extract.

Astragalus root may be available at specialty markets and can be made into tea. Injectable forms of astragalus have been used in hospitals, but studies are limited on their safety and efficacy. Inhalable forms are also available.

How to Store Astragalus

Astragalus should be stored out of sunlight in a cool dry place.

If you have an astragalus product after the "use by" date on the package has passed, don't use it and throw it away.

Keep astragalus where children and pets can't get into it.

Similar Supplements

Supplements considered similar to astragalus include:

• Panax ginseng
• American ginseng
• Garlic

Summary

Astragalus has been used for centuries in TCM. But Western research thus far is inconclusive about its safety and effectiveness for any condition. Some early research has been promising when it comes to immune support, heart disease, diabetic kidney disease, and COPD.

If you take astragalus, watch for possible side effects. Ask your healthcare provider or pharmacist about potential drug interactions, as well.

Don't take astragalus if you have an autoimmune disease, are pregnant or breastfeeding, have had an organ transplant, have chronic conditions, or take medications that it could react with. Safe dosages aren't established.