Illustration of blood flow through a narrowed artery, highlighting the limited impact of viscosity reduction.

Busting the Myth: Can Thinning Your Blood Really Improve Artery Flow?

Theo Raines in Health & Wellness December 2025 • 4 min read.

"Unclogging the Truth About Blood Viscosity and Arterial Stenosis"

Heart disease is a major health issue. Many people are exploring ways to improve blood flow, especially if they have narrowed arteries (stenosis). A common idea is that reducing blood viscosity – essentially, thinning the blood – will make it easier for blood to flow through these narrowings. This concept has led to various treatments aimed at reducing blood viscosity, but how effective are they really?

The idea behind reducing blood viscosity is simple: thinner blood should flow more easily through constricted arteries, improving oxygen delivery to tissues. Some studies have suggested that reducing blood viscosity can improve circulation, but the evidence is mixed, especially when it comes to significant arterial blockages.

This article will dive into a study that directly tested whether reducing blood viscosity improves flow through artificial stenoses (narrowings) in a controlled laboratory setting. We'll explore the study's methods, findings, and what they mean for understanding blood flow in diseased arteries. This will help you understand if viscosity reduction is really helpful.

The Stenosis Study: Does Thinning Blood Make a Difference?

Illustration of blood flow through a narrowed artery, highlighting the limited impact of viscosity reduction.

Researchers at the University of Tasmania conducted an in vitro (laboratory) experiment to investigate the effects of viscosity reduction on blood flow through narrowed arteries. They created an artificial system that mimicked a major artery with varying degrees of stenosis. The system used whole blood at different viscosity levels to simulate the effects of blood-thinning treatments.

The key question was: would reducing blood viscosity improve blood flow past a significant stenosis? To answer this, the researchers used a perfusion apparatus with 12 different-sized stenoses, ranging from 50% to 97% blockage. They then tested whole blood at three different viscosity levels, achieved by adding normal saline to thin the blood.

The Setup: A controlled system mimicking arterial stenosis in a lab.
The Variables: 12 different stenosis sizes and 3 blood viscosity levels.
The Goal: To see if reducing viscosity improves flow through the stenoses.

The results were surprising. A 36% reduction in blood viscosity, achieved by adding saline, did not significantly alter the pressure-flow relationships or the resistance to blood flow across any of the 12 stenoses. In other words, thinning the blood in this artificial system did not improve flow through the narrowed sections of the artery.

The Takeaway: Viscosity Isn't Everything

This study suggests that while viscosity reduction might improve blood flow in the microcirculation (the smallest blood vessels), it doesn't significantly improve flow through major arteries with discrete stenoses. This is an important distinction because many treatments focus on reducing viscosity as a primary strategy for improving circulation in patients with arterial disease.

The researchers concluded that reducing blood viscosity alone may not be sufficient to improve blood flow in patients with significant arterial stenosis. Other factors, such as the severity and location of the stenosis, collateral circulation (alternative pathways for blood flow), and the health of the microcirculation, may play more significant roles.

So, what does this mean for you? If you're exploring ways to improve your circulation, especially if you have known arterial blockages, it's important to consider a comprehensive approach. While viscosity reduction might be helpful in some cases, it's not a magic bullet. Focus on overall cardiovascular health, including managing cholesterol, blood pressure, and other risk factors, and work closely with your healthcare provider to determine the best course of treatment for your specific condition.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3233/ch-1988-8111, Alternate LINK

Title: Viscosity Reduction And Flow Across Artificial In Vitro Stenoses

Subject: Physiology (medical)

Journal: Clinical Hemorheology and Microcirculation

Publisher: IOS Press

Authors: D. Kilpatrick, P.S. Lavercombe, S.D. Webber

Published: 2016-12-09

Everything You Need To Know

How did the researchers in Tasmania simulate narrowed arteries to test the impact of blood viscosity?

The University of Tasmania researchers created an artificial artery system with varying degrees of stenosis, ranging from 50% to 97% blockage, and tested whole blood at three different viscosity levels. They used a perfusion apparatus to measure blood flow through these stenoses at different viscosity levels, achieved by adding normal saline to thin the blood. This allowed them to directly observe the impact of viscosity reduction on blood flow in a controlled setting.

What did the stenosis study reveal about the relationship between blood viscosity and flow through narrowed arteries?

The study demonstrated that a 36% reduction in blood viscosity did not significantly improve blood flow through the artificial stenoses. There was no notable change in the pressure-flow relationships or the resistance to blood flow across the stenoses, suggesting that thinning the blood doesn't necessarily improve flow through narrowed arteries.

Does reducing blood viscosity have any potential benefits for circulation, even if it doesn't improve flow through major arterial stenoses?

While reducing blood viscosity might not significantly improve flow through major arteries with stenoses, it may still be beneficial in the microcirculation (the smallest blood vessels). The study focused on larger arteries with discrete blockages and did not assess the impact of viscosity reduction on smaller vessels. Therefore, treatments aimed at reducing viscosity might still have a role in improving circulation at the microvascular level.

What are the implications of the stenosis study's findings for treating patients with arterial disease?

The primary implication is that treatments solely focused on reducing blood viscosity may not be effective for improving blood flow in patients with significant arterial stenosis. This suggests that other factors, such as the severity and nature of the stenosis, as well as the overall health of the blood vessels, play a more critical role in determining blood flow. This highlights the complexity of arterial disease and the need for comprehensive treatment strategies.

What aspects of blood-thinning treatments and arterial health were not addressed in the stenosis study?

This study focused solely on the mechanical effect of viscosity reduction on blood flow through artificial stenoses. It did not consider other potential effects of blood-thinning treatments, such as the impact on platelet aggregation or the risk of bleeding. Additionally, the study was conducted in vitro, which may not fully replicate the complex physiological environment of a living organism. Future research should explore the long-term effects of viscosity reduction on arterial health, considering these other factors.