What I Found in My Clients' Tests After Long COVID — And Why It Changes Everything

Before I get into the findings, let me explain the two main tests I use so the results make sense.

The Organic Acids Test (OAT) is a urine test that measures the byproducts of your cells’ metabolism — essentially, what your cells are doing and how well they’re doing it. It tells me whether your mitochondria (the energy-producing units inside every cell) are working properly, whether your body is processing fats and nutrients correctly, and whether certain inflammatory chemical pathways have been switched on. Most people have never had this test. Most doctors don’t order it.

The GI-MAP is an advanced stool test that uses DNA technology to precisely identify and quantify what’s living in your gut — bacteria, fungi, parasites — and also measures markers of gut inflammation, immune function, and how well your gut lining is holding up.

Together, these two tests give me a picture that standard bloodwork simply cannot provide.

Finding #1: The Energy Crisis at the Cell Level

In one long COVID/POTS case — completely normal on standard bloodwork, no active inflammation, autoimmune panel negative — I found ferritin at 25.1.

Let me explain why that number matters even though it “looks normal.”

Ferritin is how your body stores iron. But iron is not just for making red blood cells. Iron is a critical component of Complex IV — one of the key enzymes your mitochondria use to generate ATP, which is your cellular energy currency. When iron gets low enough, your body makes a ruthless decision: it protects your red blood cells (so you don’t look anemic on a blood test) by quietly pulling iron away from everything else — including the enzymes that produce energy, dopamine, and serotonin.

So the hemoglobin looks fine. The CBC looks fine. But the energy machinery inside the cell is running on fumes.

This is exactly why this client had crushing fatigue, brain fog, and mood collapse — and was told everything was normal. It wasn’t. Her mitochondria were iron-starved while her doctor was looking at the wrong number.

Within two weeks of correcting iron, fatigue and brain fog significantly improved. That’s not a placebo. That’s a mechanism confirming itself in real time.

Finding #2: The Silent Gut Collapse

The stool test on the same client showed calprotectin of 20 — essentially zero gut inflammation by standard interpretation. No pathogenic bacteria. No obvious infection. Most clinicians would close the file.

But the ecosystem was gutted. The butyrate-producing bacteria — the microbes that fuel the cells lining your colon — were severely depleted. The community structure had been destroyed by repeated infections, antibiotics, and the COVID insult itself.

Here’s why that matters: the cells that line your colon (colonocytes) are almost entirely dependent on a fatty acid called butyrate as their fuel source. Butyrate is produced by specific bacteria in a healthy gut. When those bacteria are gone, colonocytes start to starve. And when colonocytes starve, they cannot maintain the gut lining properly — and the lining starts to leak.

This is not a metaphor. When the gut lining breaks down, bacterial fragments — specifically a molecule called LPS (lipopolysaccharide), which is part of the outer wall of certain bacteria — cross into the bloodstream. LPS is one of the most potent inflammatory triggers the human immune system knows. When it crosses the gut barrier and hits immune receptors (called TLR4 receptors) in the bloodstream, it sets off a systemic inflammatory alarm.

And that alarm doesn’t shut off easily. Because now you have chronic low-grade inflammation running throughout the body — driving fatigue, brain fog, immune dysregulation — sourced from a gut that looked fine on the surface.

Finding #3: CD38, Sirtuin, and the NAD⁺ Collapse — This Is the Core

This is the part I want you to understand most, because it explains why long COVID doesn’t get better on its own.

When LPS enters the bloodstream and inflammation goes chronic, it triggers the upregulation of an enzyme called CD38. Think of CD38 as a pac-man for a molecule called NAD⁺ (nicotinamide adenine dinucleotide). NAD⁺ is not just an energy carrier — it is the master regulator of cellular health. It is the fuel that powers a family of proteins called sirtuins (specifically SIRT1 and SIRT3), which control mitochondrial function, DNA repair, inflammatory regulation, and the epigenetic programs that determine which genes are switched on or off.

When CD38 gets activated by chronic LPS-driven inflammation, it consumes NAD⁺ faster than the cell can make it. And when NAD⁺ drops, the sirtuins go quiet.

Here is what happens when SIRT1 and SIRT3 lose their NAD⁺ fuel:

SIRT1 normally puts a brake on NF-κB — the master inflammation switch inside the cell. Without SIRT1 activity, NF-κB stays switched on, producing more inflammatory signals, which produce more CD38, which depletes more NAD⁺. A loop that feeds itself.

SIRT3 normally maintains the function of the mitochondrial electron transport chain — the machinery that generates ATP. Without SIRT3, these complexes deteriorate. Energy production collapses further. And the mitochondria start leaking damaging reactive oxygen species (free radicals) instead of generating clean energy.

In the OAT testing I ran on another post-COVID/post-infectious client, I found direct evidence of this collapse: 3-hydroxybutyric acid elevated 4 times above range, acetoacetic acid elevated 4.7 times above range. These are ketone bodies — but not from a ketogenic diet. In a non-fasting client, these levels mean the cell cannot properly oxidize short-chain fats including butyrate. The mitochondria are not working. And a specific enzyme called SCAD — which handles the exact chain length of butyrate — was showing impairment through a marker called ethylmalonic acid.

What this means in plain language: butyrate was arriving at the colonocyte. But the colonocyte could not use it. The fuel was there. The engine wouldn’t start.

Finding #4: The Brain Chemistry Was Being Hijacked

Here is where it gets personal for anyone struggling with brain fog, low mood, anxiety, or sleep disruption after COVID.

On the same OAT testing, quinolinic acid came back at the high ceiling of the reference range. To understand why that matters, I need to explain one pathway.

COVID infection triggers a significant rise in a cytokine (inflammatory messenger) called IFN-γ. IFN-γ activates an enzyme called IDO1, which hijacks tryptophan — the amino acid your body uses to make serotonin and melatonin — and redirects it toward a different chemical pathway. The downstream product of this hijacked pathway, when it runs too hard, is quinolinic acid.

Quinolinic acid is a neurotoxin. It over-activates NMDA receptors in the brain, drives neuroinflammation, and generates oxidative damage in neurons. And simultaneously — because tryptophan is being diverted away from serotonin — the building material for serotonin itself is depleted.

This is why SSRIs often fail in post-COVID neuropsychiatric symptoms. The drug is trying to make more use of serotonin that doesn’t exist, because the precursor — tryptophan — has been rerouted. The problem is upstream of where the medication acts.

The OAT also showed pyroglutamic acid elevated — a marker of glutathione depletion, meaning the antioxidant defense system was under severe strain. The system was being hit from multiple directions simultaneously.

Finding #5: When the Microbiome Reorganizes Around the Wrong Organisms

In a separate post-COVID/post-infectious case: the microbiome test showed Prevotella copri at 44% dominance of the entire bacterial community.

In a healthy gut, no single species dominates to this degree. Prevotella copri at that level — after a viral insult — is a signal of community collapse and reorganization around an inflammatory organism. The beneficial bacteria that produce neurotransmitter precursors and butyrate were severely reduced. The OAT on this client showed high hippuric acid — a marker of aromatic fermentation from a dysbiotic community.

And the symptoms mapped exactly: immediate brain fog after eating, lasting 2-3 hours, POTS-like cardiovascular instability, inability to tolerate fermentable foods. Not because the food was the problem. Because the gut-brain axis had been destabilized from below — every meal was triggering a microbial metabolite and immune activation cascade that the autonomic nervous system was no longer equipped to buffer.

What All the Tests Are Saying in One Sentence

Post-COVID is not a mystery. It is a predictable systems failure that runs in a specific sequence:

Viral insult → LPS translocation → TLR4 activation → chronic NF-κB signaling → CD38 upregulation → NAD⁺ depletion → SIRT1/SIRT3 failure → mitochondrial collapse → colonocyte energy failure → deeper barrier breakdown → more LPS → the loop continues.

At the same time: IFN-γ → IDO1 activation → tryptophan hijacked → serotonin and melatonin depleted → quinolinic acid accumulates → neuroinflammation → brain fog, mood collapse, sleep disruption, SSRI resistance.

The bacteria are not the enemy. The gut is not the enemy. The system has been reprogrammed into a self-sustaining failure state — and standard medicine is looking at the outputs, not the engine.

Why This Doesn’t Resolve on Its Own

The most important question people ask me is: why hasn’t this gotten better with time?

Because of epigenetics.

When NAD⁺ stays depleted long enough, the enzymes that regulate DNA methylation — DNMT3A and TET2, both NAD⁺-dependent — begin to fail. This means the epigenetic programs that control which genes are on and which are off begin to drift. And those drifted programs can persist long after the original viral trigger is gone.

The virus cleared. The epigenetic disruption remained. The metabolic failure is now self-sustaining at the level of gene regulation. This is not dramatic — it is biology. And it is also why the intervention has to go upstream, to restore the metabolic conditions that allow epigenetic repair to actually happen.

If anything in this post describes what you’ve been living since COVID — the fatigue, the fog, the gut that changed, the mood that never came back — I want you to know that it has a mechanism. And mechanisms are addressable.

This is the lens I work through. If you want your case looked at this way, reach out.

— Mohammed | Biomelogic Systems biology-based consulting for complex, treatment-resistant gut and immune dysfunction

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