Insulin: A Powerful Inflammatory Peptide That Damages Arteries

When we think about insulin, most people associate it with blood sugar regulation and diabetes. While insulin does play a critical role in moving glucose from the bloodstream into cells, there is another side of insulin that is not talked about enough. In high amounts, insulin acts as a powerful inflammatory peptide that can damage the delicate lining of your arteries. Over time, this damage sets the stage for atherosclerosis, heart disease, and stroke.

At Sheen Vein (Aesthetics and Functional Medicine) here in St. Louis, we often see patients who struggle with fatigue, stubborn belly fat, or metabolic syndrome. Many don’t realize that their elevated insulin levels are not only affecting their energy and weight, but also quietly increasing their cardiovascular risk.

Insulin’s Role Beyond Blood Sugar

Insulin is a hormone, but it is also considered a peptide signaling molecule. In small amounts, it is essential for life—helping your muscles, brain, and liver use glucose for energy.

However, when the body develops insulin resistance, the pancreas compensates by producing more and more insulin. The result is chronically elevated insulin levels (hyperinsulinemia).

While blood sugar may remain “normal” for years, the persistently high insulin begins to act as an inflammatory agent, impacting nearly every system in the body—especially the cardiovascular system.

How Insulin Damages Artery Walls

The arteries are lined with a thin, protective layer called the endothelium. This lining regulates blood flow, produces nitric oxide to keep vessels flexible, and prevents dangerous plaque buildup.

Excess insulin disrupts this balance in several ways:

Promotes Inflammation
Insulin stimulates inflammatory pathways, leading to oxidative stress. This inflammation irritates the endothelial lining, making it more prone to injury.
Reduces Nitric Oxide Production
Nitric oxide is essential for vessel relaxation and smooth blood flow. High insulin levels suppress nitric oxide production, leading to stiffer, less flexible arteries—a key driver of high blood pressure.
Encourages Plaque Formation
Insulin promotes the uptake of cholesterol into arterial walls and stimulates smooth muscle cell growth, which accelerates plaque buildup.
Increases Clotting Risk
Elevated insulin thickens the blood by increasing clotting factors, making dangerous blood clots more likely.

Over time, this combination of inflammation, stiffness, and plaque development creates the perfect environment for heart attacks and strokes.

Insulin Resistance: The Hidden Cardiovascular Risk

One of the most concerning issues is that high insulin can damage arteries long before blood sugar tests reveal a problem. Many patients are told their glucose is “fine” while their insulin remains elevated and harmful.

This explains why people with metabolic syndrome—a cluster of high waist circumference, high blood pressure, elevated triglycerides, low HDL cholesterol, and insulin resistance—are at such high risk for cardiovascular disease.

Skin tags, fatigue after meals, and stubborn abdominal fat can all be outward signs of this hidden insulin-driven inflammation (see our blog on skin tags and insulin resistance).

Functional Medicine Approach in St. Louis

At Sheen Vein (Aesthetics and Functional Medicine), we go beyond standard blood sugar checks. Our evaluation often includes:

Fasting insulin levels
HOMA-IR testing (a calculation of insulin resistance)
Advanced cholesterol panels that look at particle size and inflammation markers
hs-CRP (high-sensitivity C-reactive protein) to measure inflammation directly

By detecting insulin resistance early, we can help patients lower their cardiovascular risk before major damage occurs.

Treatment focuses on:

Nutrition strategies that reduce refined carbohydrates and emphasize whole, anti-inflammatory foods
Regular exercise, which improves insulin sensitivity and endothelial health
Stress management, since chronic stress hormones worsen insulin resistance
Targeted supplements such as magnesium, omega-3 fatty acids, and berberine for blood sugar and vascular support (read more in our blog on functional medicine for cardiovascular health)
Red light therapy and metabolic support, which enhance nitric oxide production and mitochondrial health (see our blog on red light therapy and PBM)

The Bigger Picture

For too long, medicine has focused only on cholesterol as the villain in heart disease. But research is clear: insulin-driven inflammation may be just as damaging—if not more so. Elevated insulin levels injure blood vessels, accelerate plaque buildup, and contribute to the very processes that lead to heart disease.

The good news is that insulin resistance is reversible with the right interventions. By identifying the problem early, patients can prevent long-term cardiovascular complications.

Takeaway

Insulin is more than a blood sugar hormone—it is a powerful inflammatory peptide that, when elevated, can damage the arterial lining and drive heart disease. Recognizing the connection between insulin resistance and cardiovascular health allows us to intervene earlier and more effectively.

At Sheen Vein (Aesthetics and Functional Medicine) in St. Louis, we use a functional, root-cause approach to identify hidden insulin resistance and restore balance before irreversible damage occurs.

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