Long COVID Atlas
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Plain-language first, with specialist detail below. For understanding, not medical advice.

Long COVID Atlas › Glossary › Low-dose naltrexone

Treatment

Low-dose naltrexone

https://longcovidatlas.org/glossary/low-dose-naltrexone

In plain language

What it is

A familiar drug at a tiny fraction of its usual dose, used to calm inflammation.

Why it matters

It is tried off-label for long COVID fatigue and pain, with promising but unproven evidence.

Think of it like

A low setting on a familiar dial that changes what the drug does.

Why thinking feels slow bloodstream: lasting inflammation, clotting signals blood-brain barrier, now leaky microglia (brain immune cells) switch on brain fog: slow recall, poor focus,word-finding trouble
Brain fog is not laziness or anxiety. Lasting inflammation in the blood, together with a brain barrier that has become leaky, lets inflammatory signals reach brain tissue and switches on the brain's own immune cells, the microglia. That low-grade neuroinflammation is what slows recall, focus, and word-finding.

For specialists

Formal definition

Naltrexone at roughly 1 to 4.5 mg; proposed to antagonize TLR4 and modulate microglia, distinct from standard-dose opioid blockade.

Mechanism

Anti-inflammatory and microglia-modulating effects are proposed; no completed RCT in long COVID yet.

Sources

Related terms

Neuroinflammation