What Is Interleukin-6? 🔥🔥

Hi and happy Thursday!

What is interleukin-6?

Interleukin-6 (IL-6) is one of the body’s most important molecular messengers, an immune-system signal that helps coordinate how we respond to infection, stress, and injury. When something goes wrong in the body, IL-6 is one of the first responders, alerting immune cells, turning on inflammation, and even triggering fever when needed. It’s essential for healing and defence.

But IL-6 is also a double-edged sword. While short bursts of IL-6 help us recover and stay healthy, consistently elevated levels can fuel chronic inflammation, disrupt metabolism, and contribute to long-term health issues.

Why is interleukin-6 considered an inflammatory marker?

Interleukin-6 is considered an inflammatory marker because its levels rise whenever the body activates its inflammatory response, the built-in system we use to fight threats and repair damage. When immune cells detect infection, injury, or stress, they release IL-6 as a signal to ramp up defence. This cytokine then helps coordinate inflammation throughout the body: it tells the liver to produce acute-phase proteins (like C-reactive protein), activates immune cells, and helps generate fever to slow down invading pathogens.

Because IL-6 reliably increases during these processes, measuring it provides a window into how inflamed the body is at any given moment. In a healthy, short-term response, IL-6 spikes quickly and then falls once healing begins. But when IL-6 stays chronically elevated, due to ongoing stress, poor sleep, excess body fat, autoimmune disease, or persistent infection, it becomes a sign of long-term, low-grade inflammation, the type linked to many chronic health conditions.

What are typical reference ranges?

What’s next?

Next week, I will show you my Interleukin-6 levels.

For any new readers: I am trying to live to (at least) 151. To get there, I follow 2 main principles:

Live a super-healthy life (based on what science deems positive for longevity)

Measure what’s going on in my body and tune any metrics that are off to become optimal

I also summarize interesting news and stories from the longevity space. And I share everything worth sharing with you.

If you enjoyed this newsletter, I would be very grateful if you gave it a ‘like’ (the ❤️ at the top).

Have a good day,
Johan

Here is an overview of all the tests I have taken so far: