Astragalus vs. Astragaloside IV, which is better for kidney health?

Of recent Astragalus extracts have become particularly popular in the bodybuilding community with the goal to improve kidney health. The efficacy of this notion has long been questioned in our team at Strom due to variable outcomes in blood testing. However I think an evidence based answer can be provided.

Astragaloside IV appears to be a viable compound to improving liver health in models and animal trials, but NOT supplementing with whole Astragalus extracts without demonstrated Astragaloside IV content.

Considering non-standardised Astragalus extracts is the bulk of what you will see in the industry, this is not a statement we make lightly… especially given a number of the “leading evidence based” brands still continue to manufacture such inadequate products kidney health supplements.

First to address the efficacy of Astragaloside IV.

Does Astragaloside IV improve kidney health in humans?

As of February 2024, there doesn’t appear to be any human clinical trials investigating the standalone compound Astragaloside IV. This should frame the entire discussion going forward.

We do have an abundance of animal and cell culture research showing indications for anti-inflammatory activities that is protective not only for kidney tissue, but also brain, liver and more.

Research showing Astragalus and other Astragaloside IV combinations improve kidney function is also available, however we need to be careful about what results we view as valid.

Why don’t whole Astragalus extracts reliably improve kidney health?

Simply put, non-standardised Astragalus extracts do not reliably contain any detectable Astragaloside IV, and currently we do not have reason to believe Astragalus has significant kidney health promoting effects without Astragaloside IV.

According to multiple studies testing Astragalus supplements, less than a quarter of those tested has detectable Astragaloside IV present. But even those that had it present, the concentration present is so low that reaching an efficacious dose would not be practical.

The highest concentration astragalus extract contained 0.02% Astragaloside IV.

Currently accepted dosing of Astragaloside IV in humans is in the range of 5 - 50mg.

Hence in order to reach the low dose of 5mg Astragaloside IV 4 grams of that Astragalus extract would need to be consumed daily. That's about 6 capsules just for the lowest dose and the highest performing extract! To obtain a stronger dose of 25mg like that in the Leviathan Kidney Support, that would translate to 20g of the same extract, think ~30 capsules.

But Astragalus does decrease creatinine and creatinine derived eGFR?

Yes it does, but important to acknowledge is that creatinine and eGFR derived from creatinine concentrations aren’t synonymous with kidney health, only indicators. While it can be useful in normal populations to easily and cheaply provide a warning for kidney health, it is not a direct measure of kidney health and is highly variable, making it often misleading.

However there is another blood test marker available for testing to indicate rate of kidney filtration, that is Cystatin C. This is a more reliable marker due to being less susceptible to variability. And if the the trend of these two markers are compared they should follow the same curve. If you want more details as to why creatinine and eGFR derived from creatinine is a poor measure of kidney health for athletes, and why Cystatin C is preferable, read this article here.

In human research regarding Astragalus extracts, creatinine levels are often lowered, but many papers do not investigate Cystatin C, or those that do show no decrease in Cystatin C. Hence indicating that compounds within astragalus are decreasing the detectable creatinine in circulation, which does not in itself improve kidney health but is rather masking what would otherwise indicate poor kidney health. For if Kidney health was truly improved, cystatin C should also decrease proportionally to how much creatinine decreased.

How does Astragalus decrease tested creatinine concentration without improving kidney filtration rate?

This is not currently known. However there are some known pathways that can increase creatinine clearance separate to kidney health. One of which is by altering transporter activity.

So what Astragalus supplementation would we recommend?

Right at this moment the best approach Astragalus supplementation approach would appear to be using the synthetic Astragaloside IV compound. There are also a number of herbal Astragalus products on the market claiming to be high concentrations of Astragaloside IV, but right now we would still put them in the suspect category and require more independent support hat such levels of extraction are possible.

Of what we stock in store, our top recommendation is the Leviathan Kidney Support product which utilises 25mg of synthetic Astragaloside IV, however we do also have a number of other health products which use whole astragalus extracts if that is the approach you want to take.

You have been informed of our position, now its time for you to decide for yourself.

- Thomas, Strom Downunder

Release: 05.03.2024

Further Reading

Pharmacological Effects of Astragaloside IV: A Review (July 2023)

You can also email thomas@stromsports.co.nz for our full list of relevant research.