What long COVID is
Real, biological, and probably several conditions at once.
If standard tests came back normal and you were told it was in your head, this page is the counter-evidence, drawn straight from the research.
What long COVID is
Long COVID is the illness that continues, returns, or first appears in the months after a SARS-CoV-2 infection. It is real, it is biological, and it is probably several overlapping conditions rather than one.
By the 2024 National Academies definition, long COVID is an infection-associated chronic condition that occurs after SARS-CoV-2 infection and is present for at least three months — continuously, in a relapsing-and-remitting pattern, or progressively — and it can affect one or more organ systems. The World Health Organization uses a similar three-month threshold for what it calls post-COVID-19 condition.
It can follow any SARS-CoV-2 infection, including mild or asymptomatic ones, and it affects children as well as adults. There is no single lab test that confirms it and no minimum severity of the original illness required — part of why it has so often been missed or dismissed. It is also common: the WHO has cited a conservative estimate of more than 77 million people living with the condition worldwide.
It is biological, not imagined
When the routine tests most patients receive come back normal, that does not mean nothing is wrong. Specialized testing repeatedly finds measurable abnormalities — in the autonomic nervous system, the small blood vessels, the mitochondria, and elsewhere. A normal standard test rules some things out; it does not rule out long COVID.
Probably several conditions at once
Rather than one disease, long COVID looks like a family of overlapping ones. The mechanisms above feed into recognisable symptom clusters: fatigue and post-exertional malaise, autonomic problems and POTS, brain fog, cardiopulmonary symptoms, gut symptoms, and mood and sleep changes.
One thing matters most for safety
If you experience post-exertional malaise — a delayed crash after even modest physical, mental, or emotional effort — the usual advice to gradually exercise more can cause lasting harm. When PEM is present, pacing comes first. If this is you, start with the safety page before anything else.
This atlas maps what is known — the mechanisms, the symptom clusters, the tests that can document the problem, and the treatments that have been tried — each marked with how strong the evidence is and how well it holds up. Where there is no cure yet, it says so.
How to read this page
Claims on this site are tagged so you can weigh them quickly, without treating every row as equally proven.
gradeHow strong the underlying evidence is.
Example: a finding from multiple controlled studies grades stronger than one from case reports or animal work.
auditHow reliable the claim remains after tracing its sources.
Example: a claim repeated across many reviews can still be weak if those reviews all cite the same small study.
A claim can have a strong grade but a weak audit, or the reverse — so both are shown.
endpointWhat was actually measured.
Example: “felt better” is a patient-reported outcome; improved oxygen levels or imaging is something different.
safety / conflictCautions about harm, bias, or financial interests.
Example: an approach can look promising yet carry harm, or rest mainly on manufacturer-run evidence.
AIt is real, even when standard tests look normal
Across the graph, 9 findings show measurable abnormality that routine tests miss. Specialized testing sees what standard panels do not.
- Dysautonomia / autonomic dysfunction
- Fibrinaloid microclots / coagulopathy
- Endothelial dysfunction
- Mitochondrial / metabolic dysfunction
- Exercise intolerance / reduced VO2
- Impaired alveolar-capillary gas transfer (RBC:tissue-plasma, low TLco)
- Subclinical myocardial strain / reduced GLS
- Hyperpolarized 129Xe MRI / DLCO
BIt is several overlapping conditions
In many people a persistent viral reservoir appears to set off the other mechanisms, which then drive the symptom clusters. Persistence is documented in a subset, not everyone, which is why no single story fits all patients.
Viral persistence drives Immune dysregulation & autoimmunity (pathogenic IgG). full page →
Viral persistence drives Gut-serotonin axis.
Viral persistence drives Gut dysbiosis (SCFA-producer depletion, pathobiont enrichment). full page →
CIt affects nearly every system
The atlas maps 8 body systems. Each has its own front door from the homepage.
DNo cure yet, and we say so
39 treatments are catalogued, each opening with what is and isn't known. Some were tested and failed outright:
- Metformintested, did not workgradenegative
- CBT / CBT-I (supportive)tested, did not workgradenegative
- Ivabradinetested, did not workgradenegative
EMood and thinking changes are biological too
Depression, anxiety, and brain fog in long COVID track with inflammation, blood-brain-barrier changes, and serotonin disruption. They are not simply a reaction to being unwell. The mood and cognitive sections carry that evidence on every claim.