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Nutrition

The Add-On That Boosted Arginine Absorption 17% in a Small Trial

Dr. Gymbro · · 4 min read
#supplements #pre workout #nitric oxide #arginine #astragalus #ginseng #adma

Your arginine pre-workout might be leaving something on the table. A 2023 crossover trial found that pairing 5 g of arginine with a capsule of Astragalus and Panax notoginseng saponins (APS) raised arginine absorption and shifted several nitric oxide (NO) markers. One number jumped far more than the rest: the arginine-to-ADMA ratio rose 167.1%.

Before you add anything to your shaker, here is what the study did and didn't show.

What the Study Actually Was

The paper, published in Functional Foods in Health and Disease (2023;13(6):307-19, registered as NCT05024123), is a randomized, double-blind, placebo-controlled crossover pharmacokinetic study. Healthy adults aged 20 to 80 took 5 g of arginine powder with either one capsule of APS or a placebo. Each participant did both conditions, with a washout period in between. Researchers collected plasma and urine to track arginine levels and NO-related markers.

The authors say they know of no earlier human trials of Astragalus and ginseng extracts on NO levels. So this is early-stage work.

The Headline Numbers

Compared with arginine plus placebo, arginine plus APS produced:

  • Arginine AUC +17.3% (p = 0.041). AUC is a measure of total exposure, so this is the "absorbed more arginine" result.
  • Arginine Cmax +11.1%. This is the peak blood concentration. The abstract gives no p-value for it.
  • Arg/ADMA ratio +167.1% (p = 0.007). ADMA (asymmetric dimethylarginine) works against the enzyme that makes NO, so a higher ratio points toward a friendlier environment for NO production.
  • Urinary nitrate +20.8% and urinary cGMP +18.9%. Both are downstream NO markers. The abstract gives no significance values for these.

The authors conclude that APS improved arginine absorption, lowered ADMA, and enhanced NO production.

Why Lifters Should Care (and Why They Shouldn't Overreact)

Arginine is a staple of pre-workout formulas because it is a precursor to NO, which is tied to vasodilation. The usual complaint is that oral arginine doesn't reliably translate into meaningful NO changes. A compound that nudges absorption up and ADMA down is an appealing idea. The authors suggest APS could be useful for pre-workout and cardiovascular health.

That suggestion goes beyond the data, though. This study measured blood and urine markers. It did not measure workout performance, pump, strength, endurance, or blood flow during exercise. Nobody lifted anything. A higher NO marker is not the same as a better session.

The Caveats You Need to Know

1. Six people were thrown out. Thirty participants were evidently enrolled, since 24 were analysed after six were excluded for "great individual differences." That is 20% of the sample. Excluding people because their responses varied widely can make an effect look cleaner than it would be in the real world. The abstract does not say how this criterion was defined. Whether these six would have weakened the result is unknown.

2. Small sample. Twenty-four analysed participants is modest, and the p-value for the AUC result (0.041) is close to the usual cutoff.

3. Healthy people only. The results say nothing about people with cardiovascular disease, high blood pressure, or those taking medications.

4. Single-dose design. The abstract describes one arginine dose with one APS capsule. It reports nothing on long-term use or on repeated dosing.

5. Surrogate markers. Urinary nitrate and cGMP are indirect readouts of NO activity, not direct measures of vascular function.

6. Details I couldn't verify. I worked from the abstract and publication record. The APS dose per capsule, product composition, funding, and any conflicts of interest are in the full text, so check it yourself before drawing conclusions.

Practical Takeaways

Dose tested: 5 g of arginine powder with one APS capsule. The abstract doesn't state the saponin content of the capsule, so you can't replicate it from this information alone. Matching a retail product to the trial's standardized extract is not possible from the abstract.

Timing: The abstract doesn't specify how long before exercise the doses were taken, and no exercise was involved. Don't treat any specific pre-workout window as validated by this paper.

Who it might be relevant to: Healthy adults who already use arginine and are curious about absorption. The trial included ages 20 to 80, but only healthy volunteers.

Who should skip it or ask first:

  • Anyone with a heart condition, blood pressure problems, or on cardiovascular medication
  • Anyone taking blood thinners or other prescription drugs, since interactions weren't assessed in this trial
  • Pregnant or breastfeeding people and anyone with a chronic illness
  • Anyone expecting a proven performance boost, because this study didn't test performance

The abstract also says nothing on cost, so the "cheap add-on" label would be an assumption.

The Bottom Line

This small, tightly controlled crossover trial gives a credible early signal that APS may improve how the body handles an arginine dose and shift NO-related markers in the right direction. The 167% jump in the Arg/ADMA ratio is the standout finding. The exclusion of six participants, the small sample, the lack of significance values for some markers, and the absence of any performance outcome mean it is a hypothesis-builder, not a reason to overhaul your stack. The next step is a larger trial that tests exercise outcomes and reports on everyone enrolled.

Original study

Read the original research on doi.org →

This article summarizes published research for general information. It is not medical advice.

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Dr. Gymbro

Dr. Gymbro writes for Dr. Gymbro: science-backed fitness, nutrition & performance.

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