What Is Neuroinflammation, and Why It Drives So Much Pain

If you take pain seriously, you have probably noticed that it does not always behave the way the textbook diagram suggests. A sprained ankle is supposed to hurt while it heals and then stop. Yet many people find that the ache outlasts the injury, or returns on days when nothing has gone wrong. For a long time that was treated as a mystery, or worse, as something imagined. The better explanation, now well supported, is that the nervous system has its own immune response, and when that response stays switched on it keeps pain alive. That process has a name: neuroinflammation.

Key Takeaways

• Neuroinflammation is inflammation that occurs inside the nervous system itself, driven mainly by two immune-like cell types: microglia in the brain and spinal cord, and mast cells in surrounding tissue.
• When these cells stay activated, they release signaling molecules that make pain-carrying nerves more sensitive, so ordinary signals are read as painful.
• This helps explain why so much everyday and persistent pain does not match the amount of tissue damage present.
• Palmitoylethanolamide (PEA), a compound the body makes on its own, works partly by helping to calm these same cells, which is why it has drawn attention as a daily-use option for pain support.*

What Is Neuroinflammation, Exactly?

Neuroinflammation is inflammation that takes place inside the nervous system, meaning the brain, the spinal cord, and the nerves that run through the body. This is different from the familiar redness and swelling you see around a cut or a strained muscle. It happens where you cannot see it, and it is carried out by specialized cells that act as the nervous system's own immune force.

The two most important players are microglia and mast cells. Microglia are resident immune cells of the brain and spinal cord. In their resting state they survey their surroundings quietly, clearing debris and keeping neurons healthy. Mast cells sit near nerves and blood vessels throughout the body and release inflammatory messengers when triggered. Under normal conditions both are protective. The problem begins when they shift into a persistently activated state and do not stand down.

How Neuroinflammation Drives Pain: Sensitized Nerves, Not Just Injured Tissue

The central idea is that neuroinflammation lowers the threshold at which nerves report pain. When microglia and mast cells activate, they release signaling molecules, including cytokines and other mediators, that act on nearby pain-carrying neurons. Those neurons become easier to fire. Signals that would normally register as mild pressure or warmth can start to register as pain, and genuinely painful signals are amplified.

Researchers describe this as central sensitization: the volume knob on the pain system has been turned up, and it stays up as long as the underlying cells remain active. This is why pain can persist after tissue has healed. The original injury may be long gone, but the nervous system has not returned to baseline.

Microglia: The Brain's Standing Guard

Microglia are the reason pain can become self-sustaining. Once activated, they can release mediators that recruit and activate still more microglia, a loop that keeps the pain system primed. This shift from a resting to a reactive state is one of the better-characterized features of persistent pain in the current literature.¹

Mast Cells: The Local Amplifier

Mast cells work closer to the site. When they degranulate, they release histamine and other inflammatory compounds that irritate and sensitize the nerve endings around them. Because mast cells sit right next to peripheral nerves, they form a fast local feedback loop, tissue signals to mast cell, mast cell sensitizes nerve, and the cycle continues.¹

Why This Matters for Everyday Pain: A Wider Reach Than It Sounds

It would be easy to assume neuroinflammation belongs only to rare or severe conditions. The more useful point is how ordinary it is. The same sensitizing machinery is thought to contribute to a wide range of common complaints, from lingering back pain and joint discomfort to the diffuse aches that do not map neatly onto any single injury.

This reframes a frustration many people share. If your pain seems out of proportion to what you can point to, that does not mean it is not real, and it does not mean you are imagining it. It may mean the nervous system's own inflammatory response is part of the picture. That is a meaningful distinction, because it points toward a different kind of target: calming the cells that keep pain switched on, rather than only addressing tissue.

Calming the Response: Where PEA Enters the Picture

If activated microglia and mast cells are a driver of persistent pain, then a compound that helps calm those cells is worth understanding. This is where palmitoylethanolamide, or PEA, becomes relevant. PEA is a fatty-acid compound the body produces on its own, and production tends to rise in tissue under stress, which suggests it is part of the body's built-in effort to keep inflammation in check.

The mechanism has been characterized in detail. A 2025 review describes how PEA acts largely through PPAR-alpha, a receptor that helps regulate inflammatory gene activity, and in doing so contributes to the stabilization of mast cells and microglia, the same two cell types at the center of neuroinflammation.² Rather than blunting a single downstream signal, PEA appears to act upstream, on the cells that keep the pain system sensitized. We cover exactly how in the companion piece on how PEA calms neuroinflammation.

The Bigger Picture

Neuroinflammation reframes a lot of everyday pain. Much of what people carry day to day is less about ongoing tissue damage and more about a nervous system whose own immune cells have stayed switched on. That is why an approach aimed at calming those cells, rather than only masking the signal, is a sound daily-use strategy. Relivaid is built around this idea: a bio-optimized form of PEA, paired with ginger and a low 50 mg dose of caffeine in its deep maroon capsule, formulated to support the body's own inflammation-regulating pathways and safe for daily use.*

References

1. Di Stefano V, et al. Biomedicines. 2025. doi:10.3390/biomedicines13061271.